Method of calculating speckle-reduced hologram data using a convergence light wave for a computer-generated hologram
Yuji Sakamoto, Tatsuya Oshinomi, Koki Matsuno
Applied Optics, 62, 8, 1970, 1976, Optica Publishing Group, 02 Mar. 2023, [Peer-reviewed], [Lead author]
Scientific journal, In a computer-generated hologram, random phases are required for representing object surfaces; however, speckle noise occurs in the random phases. We propose a speckle reduction method for three-dimensional virtual images in electro-holography. The method does not have random phases but instead converges the object light on the observer’s viewpoint. Optical experiments demonstrated that the proposed method greatly reduced speckle noise while maintaining a calculation time comparable to that of the conventional method.

Method for generating planar computer-generated hologram at free viewpoint from cylindrical object light
Tatsuhiko Baba, Ryotaro Kon, Yuji Sakamoto
Optical Engineering, 61, 11, 113101-1, 113101-13, SPIE-Intl Soc Optical Eng, 02 Nov. 2022, [Peer-reviewed]
Scientific journal

Fast calculation method based on hidden region continuity for computer-generated holograms with multiple cameras in a sports scene
Ryosuke Watanabe, Ryota Koiso, Keisuke Nonaka, Yuji Sakamoto, Tatuya Kobayashi
Applied Optics, 61, 5, B64, B64, Optica Publishing Group, 10 Feb. 2022, [Peer-reviewed]
Scientific journal, We propose, to the best of our knowledge, the world’s first system capable of fast calculating computer-generated holograms (CGHs) from a large-scale outdoor sports scene captured with multiple RGB cameras. In the system, we introduce a fast calculation method focusing on hidden region continuity (HRC) that frequently appears in a point cloud of a 3D sports scene generated from free-viewpoint video technology. The experimental results show that the calculation time of the proposed HRC method is five to ten times faster than that of the point-based method, which is one of the common CGH calculation methods.

Autotuning GPU code for acceleration of CGH calculation
Hayato Sakai, Yuji Sakamoto
Optical Engineering, 61, 02, 023102, SPIE-Intl Soc Optical Eng, 09 Feb. 2022, [Peer-reviewed]
Scientific journal

筋電位による発話単語の音節の長さの推定　　　　　　　　　　　　　　　
宮坂 清貴, 坂本 雄児, 山ノ井 髙洋
知能と情報（日本知能情報ファジィ学会誌）, 33, 3, 718, 722, Aug. 2021, [Peer-reviewed]
Japanese, Scientific journal

Speckleless reconstructed image display using convergent light in CGH　　　　　　　　　　　　　　　
Tatsuya Oshinomi, Masaya Mitobe, Yuji Sakamoto
International Workshop on Advanced Image Technology 2021 (IWAIT2021), Poster Session 1, Jan. 2021, [Peer-reviewed]
English

Data transmission based on fractal compression of object light data in computer-generated hologram　　　　　　　　　　　　　　　
Hiroki Oi, Yuji Sakamoto
International Workshop on Advanced Image Technology 2021 (IWAIT2021), 7A, 1, Jan. 2021, [Peer-reviewed]
English, International conference proceedings

A Weight-wise Watermarking Technique for DNN Models and Its Robustness Against Overwriting Attack　　　　　　　　　　　　　　　
Han He, Seok Kang, Yuji Sakamoto
International Workshop on Advanced Image Technology 2021 (IWAIT2021), 6B, 3, Jan. 2021, [Peer-reviewed]
English, International conference proceedings

Hidden Surface Removal Method Using Object Point Based Ray Tracing in CGH　　　　　　　　　　　　　　　
Keita Watanabe, Yuji Sakamoto
International Workshop on Advanced Image Technology 2021 (IWAIT2021), 2B, 3, Jan. 2021, [Peer-reviewed]
English, International conference proceedings

Interactive 3D Model Generation from Character Illustration　　　　　　　　　　　　　　　
Nozomi Isami, Yuji Sakamoto
SIGGRAPH Asia 2020 Posters, No. 24, Dec. 2020, [Peer-reviewed]
English, International conference proceedings

Wide-Viewing Zone Electro-Holography System by Using Switching of Reconstruction Light　　　　　　　　　　　　　　　
Naruto Fujimori, Yuji Sakamoto
The 27th International Display Workshops (IDW'20), 3D4, 4, Dec. 2020, [Peer-reviewed]
English, International conference proceedings

A Parameters Sharing Watermarking Technique for Convolutional Neural Network Model　　　　　　　　　　　　　　　
Han He, Seok Kang, Yuji Sakamoto
FIT2020, K, 008, Sep. 2020, [Peer-reviewed]
English, International conference proceedings

Enlarged viewing zone using light wave propagation simulation　　　　　　　　　　　　　　　
Takahiro Kobayakawa, Yuji Sakamoto
Imaging and Applied Optics Congress, JW2A, 8, Jun. 2020, [Peer-reviewed]
English, International conference proceedings

Lossless Compression Method Using Quadtree and 4-direction Differential Pulse Coding Modulation for Hologram Data with Fourier Transform Optical System　　　　　　　　　　　　　　　
Hiroki Oi, Yuji Sakamoto
Imaging and Applied Optics Congress, JTh2A, 3, Jun. 2020, [Peer-reviewed]
English, International conference proceedings

Enlargement of viewing angle in electro-holography using time division method and multiple reconstruction lights" Lowering the Resolution Based on Fresnel Zone Plate Reduction　　　　　　　　　　　　　　　
Naruto Fujimori, Yuji Sakamoto
Imaging and Applied Optics Congress, JW2A, 11, Jun. 2020, [Peer-reviewed]
English, International conference proceedings

Auto-optimization of GPU Code for Computer-Generated Hologram Calculation　　　　　　　　　　　　　　　
Hayato Sakai, Yuji Sakamoto
Imaging and Applied Optics Congress, JTh2A, 15, Jun. 2020, [Peer-reviewed]
English, International conference proceedings

Fast calculation method with saccade suppression for a computer-generated hologram based on Fresnel zone plate limitation
Lingjie Wei, Fumio Okuyama, Yuji Sakamoto
Optics Express, 28, 9, 13368, 13368, The Optical Society, 27 Apr. 2020, [Peer-reviewed]
Scientific journal

Study on table-top optical system enlarging viewing-zone for displaying holographic aerial image　　　　　　　　　　　　　　　
Takahiro Kobayakawa, Yuji Sakamoto
SPIE OPTO, 113060R, 21 Feb. 2020, [Peer-reviewed]
English, International conference proceedings

Fast calculation by auto-optimized method in CGH video generation using GPU　　　　　　　　　　　　　　　
Hayato Sakai, Yuji Sakamoto
SPIE OPTO, 113060S, 21 Feb. 2020, [Peer-reviewed]
English

Evaluation of quality of light-waves considering transmission errors for wireless transmission system in CGHs　　　　　　　　　　　　　　　
Kazuhiro Yamaguchi, Yuji Sakamoto
Optics InfoBase Conference Papers, The Optical Society, 2020
English, International conference proceedings, In this paper, a wireless transmission system model for CGHs is constructed, and quality of light-waves considering transmission errors of transmitted CGHs with some kind of errors were evaluated by using computer simulations.

Wide visual field angle holographic display using compact electro-holographic projectors
Yasuo Ito, Masaya Mitobe, Masatoshi Nagahama, Hayato Sakai, Yuji Sakamoto
Applied Optics, 58, 34, G135, G135, The Optical Society, 01 Dec. 2019, [Peer-reviewed]
English, Scientific journal, Electro-holography has the problem of having a narrow visual field angle, because the resolution of a spatial light modulator is insufficient for displaying a fringe pattern. To solve this problem, this paper proposes a projector-type electro-holographic compact display that achieves a wide visual field angle by using the combination of an optical system and calculation algorithms. The results of experiments show that the visual field angle is three times larger than that of a normal electro-holographic display. In addition, it is demonstrated that the system has the ability to display 3D reconstructed images with binocular, full-color, high-resolution, and accurate depth presentation. (C) 2019 Optical Society of America

Fast calculation method for viewpoint movements in computer-generated holograms using a Fourier transform optical system
Ryosuke Watanabe, Takamasa Nakamura, Masaya Mitobe, Yuji Sakamoto, Sei Naito
Applied Optics, 58, 34, G71, G71, The Optical Society, 01 Dec. 2019, [Peer-reviewed], [International Magazine]
English, Scientific journal, Augmented reality (AR) using a holographic head-mounted display has been attracting a great deal of attention. In the AR system, computer-generated holograms (CGHs) are calculated and displayed on an electronic display. However, the time required for making CGHs is very long. Here, we propose a fast calculation method for arbitrary viewpoint movements in holographic AR systems. The calculation uses a Fourier transform optical system to enlarge the visual field of electroholography. In experiments, the generation time of the proposed method was approximately twice as fast as that of the conventional method. Furthermore, the quality of the CGHs generated by our method was sufficiently high.

Method to Make 3DCG Movement to Anime-Style Using Animation Technique　　　　　　　　　　　　　　　
Kei Kitahata, Yuji Sakamoto
SIGGRAPH Asia 2019 Posters (SA '19 Posters), Nov. 2019, [Peer-reviewed]
English

Fast Calculation Method for Computer-Generated Holograms Using Saccade Suppression by Lowering the Resolution Based on Fresnel Zone Plate Reduction　　　　　　　　　　　　　　　
Lingjie Wei, Fumio Okuyama, Yuji Sakamoto
The 26th International Display Workshops (IDW '19), 3DSA9/3D9, 4, Nov. 2019, [Peer-reviewed]
English

Compact Binocular Holographic Head-Mounted Display Using Viewing Zone Expansion Method with Multiple Light Sources　　　　　　　　　　　　　　　
Kazuya Furuta, Yuji Sakamoto
The 26th International Display Workshops (IDW '19), 3Dp1/3DSAp1, 1, Nov. 2019, [Peer-reviewed]
English, International conference proceedings

Lossless compression applying linear predictive coding based on the directionality of interference patterns of a hologram
Kim Duk Hyun, Kohei Tamagawa, Yuji Sakamoto
Applied Optics, 58, 18, 5018, 5018, The Optical Society, 20 Jun. 2019, [Peer-reviewed]
English, Scientific journal

Concept of Compact Head Mount Display Using Computer Generated Hologram　　　　　　　　　　　　　　　
Yuji SAKAMOTO
電子情報通信学会論文誌, J102–C, 6, 205, 211, 2019, [Peer-reviewed]
Japanese, Scientific journal

Analysis of Effect of Quantization Error on Speckle Noise in Computer-generated Hologram using Point-based Method　　　　　　　　　　　　　　　
Masaya Mitobe, Yuji Sakamoto
11th International Symposium in Display Holography (ISDH2018), Jul. 2018

A Holographic Display Method for Volume Data with Volume Rendering Method　　　　　　　　　　　　　　　
Zixiang Lu, Yuji Sakamoto
11th International Symposium in Display Holography (ISDH2018), Jul. 2018

Data hiding technique for omnidirectional JPEG images displayed on VR spaces
Yasutoshi Miura, Xuefei Li, Seok Kang, Yuji Sakamoto
2018 International Workshop on Advanced Image Technology, IWAIT 2018, G3-4, 1, 4, Institute of Electrical and Electronics Engineers Inc., 30 May 2018
English, International conference proceedings, We propose a data hading technique for images in this paper. Our technique hides additional data of images into image data area for not being separated each other easily. The proposed technique uses omnidirectional JPEG images as cover data because of the huge amount of the embeddable area. Moreover, the embedded omnidirectional image can be viewed on VR space and the embedded data are extracted and playing in VR spaces using HMDs. We verified that our technique embedded the additional image into images efficiently in terms of PSNR, payload and overhead.

Subjective evaluation of speckle noise in electro-holography
Masaya Mitobe, Yuji Sakamoto
2018 International Workshop on Advanced Image Technology, IWAIT 2018, F4-3, 1, 4, Institute of Electrical and Electronics Engineers Inc., 30 May 2018
English, International conference proceedings, In electro-holography, speckle noise is a serious problem because it deteriorates image quality. We focused on the quantization errors of electro-holography and performed a subjective evaluation to the effect of speckle noise. We evaluated reconstructed images of an object that had differences in the number of the point light sources representing the object and the quantization levels of computer-generated holograms (CGHs). We performed the subjective evaluation using Sheffe's method of paired comparison (Ura's variation). Through the evaluation, we confirmed the effect of quantization errors on speckle noise.

A scrambling technique embedding soundtracks into videos for streaming media
Xuefei Li, Yasutoshi Miura, Seok Kang, Yuji Sakamoto
2018 International Workshop on Advanced Image Technology, IWAIT 2018, A2-2, 1, 4, Institute of Electrical and Electronics Engineers Inc., 30 May 2018
English, International conference proceedings, In these years, streaming media have become very popular. In order to protect the legal copyright of streaming media, DRM (Digital Right Management) techniques are utilized widely. However, encryption, the most representative DRM technique, is difficult to install into real-time communication systems. In addition, existing DRM techniques for real-time communication are not supported by several widely-used web browsers. Scrambling, as a substitute to encryption, is suitable for real-time communication. In this paper, we propose a scrambling technique embedding soundtracks into videos. In the proposed technique, we embed audio data into quantized discrete cosine transform (qDCT) coefficients of the video data and generate scrambling at the same time during the video encoding process. After transmission, the streaming media data can be recovered during decoding process. We conducted experiments to investigate proper parameters to make the technique effective. Using the determined parameters, we conducted verification experiments to prove the effectiveness of the proposed technique.

A fast animation generation system for computer-generated hologram using ray-tracing method
Lingjie Wei, Yuji Sakamoto
2018 International Workshop on Advanced Image Technology, IWAIT 2018, F2-3, 1, 4, Institute of Electrical and Electronics Engineers Inc., 30 May 2018
English, International conference proceedings, CGH is a technique that simulates the recording of holography. Although CGH has a lot of advantages, it also has many disadvantages, such as a long computation time and difficulty in generating animation. In this research, we introduce an animation system for CGH that can realize the complex movements of multiple objects with a fast calculation method. The experiments demonstrate the effectiveness and high-speed calculation of the animation system.

Holographic head-mounted display with correct accommodation and vergence stimuli　　　　　　　　　　　　　　　
Takuo Yoneyama, Eishin Murakami, Yuki Oguro, Hibiki Kubo, Kazuhiro Yamaguchi, Yuji Sakamoto
Optical Engineering, 57, 6, May 2018

Holographic display methods for volume data: polygon-based and MIP-based methods
Zixiang Lu, Yuji Sakamoto
Applied Optics, 57, 1, A142, A149, OSA - The Optical Society, 01 Jan. 2018
English, Scientific journal, Volume data are widely used in many areas, especially in biomedical science and geology. However, current visualization technologies of volume data cannot satisfy the visual requirements of humans. In this study, we propose two holographic display methods for volume data. The first method is polygon-based, and the other is maximum intensity projection (MIP)-based. Both methods are able to generate computer generated holograms of volume data. The polygon-based method can obtain various and colorful holograms, while the MIP-based method can be quickly calculated. Both methods can generate holographic animations, which were displayed on an electro-holography device.

Color Compact Head-Mounted Holographic Display Using Laser Diodes　　　　　　　　　　　　　　　
Hibiki Kubo, Yuki Oguro, Yuji Sakamoto
The 24th International Display Workshops (IDW '17), 3D, 1, 7, Dec. 2017

Automatic Lens Distortion Correction Method for Compact Holographic HMD　　　　　　　　　　　　　　　
Yuki Oguro, Yuji Sakamoto
International Workshop on Holography and related technologies 2017, 24a5, Nov. 2017

Analysis of Transient Visual Evoked Potential on Electro-holographic Image　　　　　　　　　　　　　　　
Takemitsu Mizuki, Masataka Fujiwara, Yuji Sakamoto
International Workshop on Holography and related technologies 2017, P8, Nov. 2017

Development of Holo-HMD and remaining issue　　　　　　　　　　　　　　　
Yuji Sakamoto
International Workshop on Holography and related technologies 2017, 23a4, Nov. 2017

Study on compact head-mounted display system using electro-holography for augmented reality
Eishin Murakami, Yuki Oguro, Yuji Sakamoto
IEICE Transactions on Electronics, E100C, 11, 965, 971, Institute of Electronics, Information and Communication, Engineers, IEICE, 01 Nov. 2017
English, Scientific journal, Head-mounted displays (HMDs) and augmented reality (AR) are actively being studied. However, ordinary AR HMDs for visual assistance have a problem in which users have difficulty simultaneously focusing their eyes on both the real target object and the displayed image because the image can only be displayed at a fixed distance from an user's eyes in contrast to where the real object three-dimensionally exists. Therefore, we considered incorporating a holographic technology, an ideal three-dimensional (3D) display technology, into an AR HMD system. A few studies on holographic HMDs have had technical problems, and they have faults in size and weight. This paper proposes a compact holographic AR HMD system with the purpose of enabling an ideal 3D AR HMD system which can correctly reconstruct the image at any depth. In this paper, a Fourier transform optical system (FTOS) was implemented using only one lens in order to achieve a compact and lightweight structure, and a compact holographic AR HMD system was constructed. The experimental results showed that the proposed system can reconstruct sharp images at the correct depth for a wide depth range. This study enabled an ideal 3D AR HMD system that enables simultaneous viewing of both the real target object and the reconstructed image without feeling visual fatigue.

Dynamic visual responses of accommodation and vergence to electro-holographic images
Aya Nozaki, Masaya Mitobe, Fumio Okuyama, Yuji Sakamoto
OPTICS EXPRESS, 25, 4, 4542, 4551, OPTICAL SOC AMER, Feb. 2017
English, Scientific journal, Electro-holography can display images without inducing fatigue and three-dimensional (3D) sickness, i.e., visual discomfort due to viewing a stereoscopic display. Thus, this technology is expected to be applied to 3D media. However, there are no studies that have shown the agreement between the dynamic responses of accommodation and vergence to the reconstructed images of electro-holography and those to the real targets. This paper describes the measurement results of these responses using a developed system that can simultaneously measure the dynamic responses of accommodation and vergence. Moreover, statistical analysis for associating the accommodation and the vergence responses was achieved, and our study confirmed that these responses were in agreement. (C) 2017 Optical Society of America

A holographic display method of medical images with modified ray tracing method
Zixiang Lu, Yuji Sakamoto
Optics InfoBase Conference Papers, 2017, 4, OSA - The Optical Society, 2017
English, International conference proceedings, Medical images are difficult to understand for people who do not have enough medical knowledges. In this study, a holographic display method with modified ray tracing method was proposed to make them easy to understand.

Head-mounted holographic display with correct depthfocusing for AR
Yuji Sakamoto
Optics InfoBase Conference Papers, 2017, FTu4C.2., OSA - The Optical Society, 2017
English, International conference proceedings, A compact and lightweight head-mounted holographic display based on computergenerated hologram for AR was developed. It shows 3D images at correct depth-focusing without fatigue by the depth difference with the gazing object.

Reversible Privacy Protection Technique for Surveillance Camera Images
Yamamoto Yasunori, Li Xuefei, Shimaura Shingo, Kang Seok, Sakamoto Yuji
The Journal of the Institute of Image Information and Television Engineers, 71, 3, J110, J117, 一般社団法人 映像情報メディア学会, 2017, [Peer-reviewed]
Japanese, 近年，監視カメラ映像におけるプライバシー侵害の問題が注目されている．これまでの可逆的プライバシー保護手法では記録画像の流出による第三者からのプライバシー侵害行為を防ぐことができるが，監視者が確認する記録画像にはプライバシー保護処理が施されていないため，悪意ある監視者によるプライバシー侵害行為を防ぐことができない．監視者が確認する記録画像に対するプライバシー保護手法として，目標画質より算出された二乗誤差を基準としたスクランブル処理とヒストグラム操作による復元に関わる情報の埋め込み処理を組み合わせた手法がある．そこで本稿ではその手法に改良を加え，処理時間を大幅に短縮し，実用に耐えうる技法を実現した．また，改良した手法において，スクランブル強度制御実験，プライバシー保護レベル評価実験および動作の検出実験，さらに単位画像あたりの処理時間測定によるリアルタイム性評価実験を行い，その有効性を確認した．

Full-color large-scaled computer-generated holograms for physical and non-physical objects
Matsushima, Kyoji, Tsuchiyama, Yasuhiro, Sonobe, Noriaki, Masuji, Shoya, Yamaguchi, Masahiro, Sakamoto, Yuji
Holography: Advances and Modern Trends V, 10233, 2017, [Peer-reviewed]

Full-color high-definition CGH reconstructing hybrid scenes of physical and virtual objects
Tsuchiyama, Yasuhiro, Matsushima, Kyoji, Nakahara, Sumio, Yamaguchi, Masahiro, Sakamoto, Yuji
Practical Holography Xxxi: Materials and Applications, 10127, 2017, [Peer-reviewed]

A Holographic Display method of Maximum Intensity Projection of Medical Image by Electro-holography　　　　　　　　　　　　　　　
Zixiang Lu, Yuji Sakamoto
The Sixth Japan-Korea Workshop on Digital Holography and Information Photonics, 20, 30, Dec. 2016

Fast Calculation Method Considering Hidden Surface Removal for Computer-Generated Holograms using Geometric Sequence　　　　　　　　　　　　　　　
Takuya Sugawara, Yuji Sakamoto
The Sixth Japan-Korea Workshop on Digital Holography and Information Photonics, 20, 25, Dec. 2016

Development of a Measurement System for Dynamic Visual Responses to Images of Electro-holography and Binocular Stereo Vision　　　　　　　　　　　　　　　
Aya Nozaki, Fumio Okuyama, Yuji Sakamoto
he Sixth Japan-Korea Workshop on Digital Holography and Information Photonics, 20, 24, Dec. 2016

Study on Holographic Monocle Device　　　　　　　　　　　　　　　
Yuji Sakamoto
The Sixth Japan-Korea Workshop on Digital Holography and Information Photonics, Inv20, a4, Dec. 2016

Study on Compact Holographic Head-Mounted Display for Augmented Reality　　　　　　　　　　　　　　　
E. Murakami, Y. Oguro, Y. Sakamoto
The 23rd International Display Workshops in conjunction with Asia Display 2016, 3Dp1/3DSA, 1, 10, Dec. 2016, [Peer-reviewed]
IDW/AD '16 Outstanding Poster Paper Award

Influence of Transmission Error on Reconstructed-image Quality in Electro-holography
Yamaguchi Kazuhiro, Watanabe Ryosuke, Nozaki Aya, Sakamoto Yuji
The Journal of The Institute of Image Information and Television Engineers, 70, 5, J105, J113, The Institute of Image Information and Television Engineers, 2016
Japanese, 本研究では，ホログラムデータの無線伝送時において，無線伝送エラーが電子ホログラフィの再生像に対してどのような影響を与えるのか被験者を用いた主観評価および再生像の撮影画像を用いた客観評価を行った結果を報告している．CGH（Computer-Generated Hologram）により生成したホログラムデータを無線伝送シミュレータにより無線伝送し，SSIM（Structural Similarity）を用いた客観評価とDSCQS（Double Stimulus Continuous Quality Scale）法を用いた主観評価の結果を比較したところ，ビットエラー率BER（Bit Error ratio）が10^-3以下では，無線伝送による伝送エラーはホログラムの再生像にほとんど影響を与えないことを明らかにした．

Subjective Evaluation of Scrambled Images Using Reversible Privacy Protection Technique　　　　　　　　　　　　　　　
Yasunori Yamamoto, Seok Kang, Yuji Sakamoto
International Workshop on Advanced Image Technology 2016, 2C, 4, Jan. 2016

Fast calculation method of computer generated hologram animation for viewpoint parallel shift and rotation using Fourier transform optical system
Ryosuke Watanabe, Kazuhiro Yamaguchi, Yuji Sakamoto
APPLIED OPTICS, 55, 3, A167, A177, OPTICAL SOC AMER, Jan. 2016
English, Scientific journal, Computer generated hologram (CGH) animations can be made by switching many CGHs on an electronic display. Some fast calculation methods for CGH animations have been proposed, but one for viewpoint movement has not been proposed. Therefore, we designed a fast calculation method of CGH animations for viewpoint parallel shifts and rotation. A Fourier transform optical system was adopted to expand the viewing angle. The results of experiments were that the calculation time of our method was over 6 times faster than that of the conventional method. Furthermore, the degradation in CGH animation quality was found to be sufficiently small. (C) 2016 Optical Society of America

Fast point-based method of a computer-generated hologram for a triangle-patch model by using a graphics processing unit
Takuya Sugawara, Yuki Ogihara, Yuji Sakamoto
APPLIED OPTICS, 55, 3, A160, A166, OPTICAL SOC AMER, Jan. 2016
English, Scientific journal, The point-based method and fast-Fourier-transform-based method are commonly used for calculation methods of computer-generation holograms. This paper proposes a novel fast calculation method for a patch model, which uses the point-based method. The method provides a calculation time that is proportional to the number of patches but not to that of the point light sources. This means that the method is suitable for calculating a wide area covered by patches quickly. Experiments using a graphics processing unit indicated that the proposed method is about 8 times or more faster than the ordinary point-based method. (C) 2016 Optical Society of America

A Partial Scrambling Technique with Adjustable Degradation Degrees Embedding Different Types of Contents　　　　　　　　　　　　　　　
Xuefei Li, Seok Kang, Yuji Sakamoto
International Workshop on Advanced Image Technology 2016, 2C, 5, Jan. 2016
IWAIT 2016 Best Paper Awards

Viewing Zone Expansion Method by Switching LEDs for Holographic HMD Based on Fourier Transform Optical System　　　　　　　　　　　　　　　
Eishin Murakami, Ryosuke Watanabe, Yuji Sakamoto
International Workshop on Holography and related technologies 2015, We5, P11, Nov. 2015

Fast Generation Method of CGH Animation for Viewpoint Movement using Fourier Transform Optical System　　　　　　　　　　　　　　　
Ryosuke Watanabe, Yuji Sakamoto
International Workshop on Holography and related technologies 2015, We5, P10, Nov. 2015

Fast Calculation Method for Computer-generated Holograms using Geometric Sequence on Fourier Transform Optical System　　　　　　　　　　　　　　　
Takuya Sugawara, Yuji Sakamoto
International Workshop on Holography and related technologies 2015, We5, P9, Nov. 2015

Simultaneous Measurement of Dynamic Vergence and Accommodation Responses to Reconstructed Images of Electro-holography　　　　　　　　　　　　　　　
Aya Nozaki, Fumio Okuyama, Yuji Sakamoto
International Workshop on Holography and related technologies 2015, We5, P7, Nov. 2015

(Plenary)"Futures can be invented" - Remaining issues of electro-holography and CGH　　　　　　　　　　　　　　　
Yuji Sakamoto
The 5th Korea-Japan Workshop on Digital Holography and Information Photonics, Session 1, Sep. 2015

Fast calculation method of computer generated hologram using ray tracing method for Fourier transform optical system　　　　　　　　　　　　　　　
Ryosuke Watanabe, Takuya Sugawara, Yuji Sakamoto
10th International Symposium on Display Holography, P-16, Jul. 2015

Fast calculation of CGH for rectangular patch model　　　　　　　　　　　　　　　
Yuji Sakamoto, Yuki Ogihara, Takuya Sugawara
10th International Symposium on Display Holography, Jul. 2015

Computer-Generated Holograms of Actual Objects with Range Sensors and Digital Cameras Arranged Arbitrary Locations
Tai Keigo, Sakamoto Yuji
The Journal of the Institute of Television Engineers of Japan, 69, 2015年4月号, J140, J147, The Institute of Image Information and Television Engineers, Apr. 2015
Japanese, 本研究では，複数のレンジセンサとディジタルカメラから実物体のCGHを生成する手法を提案する．提案手法は，カメラキャリブレーションを用いることで装置の位置を推定するため，任意の位置に配置を行える．このため，広範囲を撮影する装置の配置が実現でき，大きな実物体からもホログラムの生成が可能となった．提案手法において，ホログラムはホログラフィックステレオグラムの原理を用いて生成される．また実験では，人間大の実物体を撮影可能なスタジオを作成し，提案手法の原理と有効性の実証を行った．

Response of accommodation and vergence to electro-holographic images
Ryuichi Ohara, Masanobu Kurita, Takuo Yoneyama, Fumio Okuyama, Yuji Sakamoto
APPLIED OPTICS, 54, 4, 615, 621, OPTICAL SOC AMER, Feb. 2015
English, Scientific journal, Studies on measuring accommodation and vergence responses of human vision are important to evaluate three-dimensional (3D) display technologies. Electro-holography is expected to be an ideal 3D display. However, there has been little research on measuring responses to it. In this study, the static responses to electro-holographic images with a large visual field and correct stimuli were measured. In addition, responses to real objects were measured for comparison with those to displayed images. There were more subjects than in conventional studies for statistical analysis. The experimental results statistically confirmed the equivalence of the responses to electro-holographic images and those to real objects. Therefore, it was experimentally suggested that electro-holography enables human vision to perform correct accommodation and vergence responses in accordance with the depths. (C) 2015 Optical Society of America

Reversible privacy protection technique combining partial scrambling and data hiding　　　　　　　　　　　　　　　
S. Shimaura, S. Kang, Y. Sakamoto
2015 Joint Conference of IWAIT and IFMIA, 123, Jan. 2015

Dynamic Responses of Accommodation and Vergence to Electro-holographic Images　　　　　　　　　　　　　　　
R. Ohara, Y. Sakamoto, F. Okuyama
2015 Joint Conference of IWAIT and IFMIA, 122, Jan. 2015

Fast calculation method of a CGH for a patch model using a point-based method
Y. Ogihara, Y. Sakamoto
APPLIED OPTICS, 54, 1, A76, A83, OPTICAL SOC AMER, Jan. 2015
English, Scientific journal, Holography is three-dimensional display technology. Computer-generated holograms (CGHs) are created by simulating light propagation on a computer, and they are able to display a virtual object. There are mainly two types of calculation methods of CGHs, a point-based method and the fast Fourier-transform (FFT)-based method. The FFT-based method is based on a patch model, and it is suited to accelerating the calculations as it calculates the light propagation across a patch as a whole. The calculations with the point-based method are characterized by a high degree of parallelism, and it is suited to accelerating graphics processing units (GPUs). The point-based method is not suitable for calculation with the patch model. This paper proposes a fast calculation algorithm for a patch model with the point-based method. The proposed method calculates the line on a patch as a whole regardless of the number of points on the line. When the proposed method is implemented on a GPU, the calculation time of the proposed method is shorter than with the point-based method. (C) 2014 Optical Society of America

Fast Calculation Algorithm Based on Point-Based Method for CGHs Using Polygon Model　　　　　　　　　　　　　　　
Yuki Ogihara, Yuji Sakamoto
IDW2014, VHF, 5-3, Dec. 2014

Computer-Generated Hologram Using Range Sensors and Digital Cameras at Arbitrary Locations　　　　　　　　　　　　　　　
K. Tai, Y. Sakamoto
IDW2014, 3D, 1, 2, Dec. 2014

Fast Generation Method for Computer-Generated Hologram Animation with Hidden Surface Removal Using Ray Tracing Method
Ryosuke Watanabe, Yuji Sakamoto
JSAP-OSA Joint Symposia (The 75th JSAP Autumn Meeting 2014), 20a, C4-7, Sep. 2014
International conference proceedings

Measurement of static convergence and accommodation response to reconstructed images of electro-holography for depth perception
Ryuichi Ohara, Takuo Yoneyama, Masanobu Kurita, Yuji Sakamoto, Fumio Okuyama
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers, 68, 4, J144, J151, Inst. of Image Information and Television Engineers, 2014
Japanese, Scientific journal, Theoretically, it is expected that a display based on an electro-holography shows three-dimensional (3D) imageswhich satisfy all physiological factors of the depth perception of persons. A novel electro-holographic display for binocular vision was fabricated for measurements of physiological responses to 3D images. The display has a wide field of view, full parallax, and also ability to display 3D images that provide accurate accommodative and convergence stimuli correlated with depth position estimated by the viewers. The vergence and accommodation responses of viewers to the 3D images were measured objectively using an infrared optometer, and moreover depth perceptions were assessed. The comparison between measured values to the images and to real objects indicated that 3D images were displayed at the correct depth position. The results suggest that an electro-holographic display satisfy physiological factors of the depth perception.

Semi-portable full-color electro-holographic display with small size
Takuo Yoneyama, Tsubasa Ichikawa, Yuji Sakamoto
PRACTICAL HOLOGRAPHY XXVIII: MATERIALS AND APPLICATIONS, 9006, SPIE-INT SOC OPTICAL ENGINEERING, 2014, [Peer-reviewed]
English, International conference proceedings, Although various 3-D head mounted displays (HMDs) using stereograms have been implemented, extended usage of those systems cause discomfort, fatigue and tiredness because stereogram do not satisfy all 3-D visual cues: accommodation, vergence, and parallax. On the other hand, electro-holography enables observers to view natural 3-D images with minimal discomfort due to satisfying these necessary cues.
This time, we fabricated a small sized full-color holographic display system with a type of binocular eyepiece for the base of the wearable system. In this paper, we describe the structure of our system and the proposed calibration method for the arrangement of the optical parts. This calibration plays an important role in the accuracy of the reconstructed images. The main optical parts are combined to a single component to keep the exact arrangement, so this system is semi-portable and can be used everywhere with only a little adjustment. The system has the slide structure between left and right view point like binoculars to eliminate the influence of individual interpupillary distances (PDs). The field sequential color method enables the system to reconstruct full-color images by this display system. The light source is a full-color LED covered with a sharpened fiber and the tip of the fiber works as an almost ideal point light source.
The results of the subjective experiments show that reconstructed full-color images are statistically located at the correct depths and satisfy correct accommodation and vergence without the influence of individual PDs.

Static Responses of Accommodation and Convergence to Holographic Images and Real Objects
Ryuichi Ohara, Takuo Yoneyama, Masanobu Kurita, Yuji Sakamoto, Fumio Okuyama
PRACTICAL HOLOGRAPHY XXVIII: MATERIALS AND APPLICATIONS, 9006, SPIE-INT SOC OPTICAL ENGINEERING, 2014, [Peer-reviewed]
English, International conference proceedings, In three dimensional display technologies, studies on measuring accommodation and convergence responses to reconstructed images have been reported. However, the physiological characteristics of responses to reconstructed electro-holographic images are not clearly known. In this research, static responses to holographic images and real targets were measured. In addition to measuring responses, tests were conducted to evaluate the depths of reconstructed images in comparison with those of real targets, subjectively. A measurement system consisting of an electro-holographic display, real targets, and an auto refractometer was fabricated to measure accommodation and convergence responses. The display for reconstructing holographic images was a binocular eyepiece - type electro-holographic display based on a Fourier transform optical system. It was confirmed by a camera in which images were located at correct depth and had correct parallax. The target was shaped like a Maltese cross and presented in positions that were 0.5, 1.0, 1.5 and 2.0 diopters from the subjects' eyes. To avoid the influence of objects except targets, all experimentations were done in a dark room. Regarding the results of the measurements, it was confirmed that accommodation and convergence responses to holographic images varied depending on the position of the targets, and the behaviors of holographic images were similar to those of real targets. In addition, results of subjective evaluation showed that holographic images were recognized at nearly the same positions as real targets. Therefore, subjects were able to perceive holographic images at nearly the same positions as real objects in stereoscopic vision.

Fast calculation with point based method to make CGHs of the polygon model
Yuki Ogihara, Tsubasa Ichikawa, Yuji Sakamoto
PRACTICAL HOLOGRAPHY XXVIII: MATERIALS AND APPLICATIONS, 9006, SPIE-INT SOC OPTICAL ENGINEERING, 2014, [Peer-reviewed]
English, International conference proceedings, Holography is one of the three-dimensional technology. Light waves from an object are recorded and reconstructed by using a hologram. Computer generated holograms (CGHs), which are made by simulating light propagation using a computer, are able to represent virtual object. However, an enormous amount of computation time is required to make CGHs. There are two primary methods of calculating CGHs: the polygon-based method and the point-based method. In the polygon-based method with Fourier transforms, CGHs are calculated using a fast Fourier transform (FFT). The calculation of complex objects composed of multiple polygons requires as many FFTs, so unfortunately the calculation time become enormous. In contrast, in the point-based method, it is easy to express complex objects, an enormous calculation time is still required. Graphics processing units (GPUs) have been used to speed up the calculations of point-based method. Because a GPU is specialized for parallel computation and CGH calculation can be calculated independently for each pixel. However, expressing a planar object by the point-based method requires a significant increase in the density of points and consequently in the number of point light sources. In this paper, we propose a fast calculation algorithm to express planar objects by the point-based method with a GPU. The proposed method accelerate calculation by obtaining the distance between a pixel and the point light source from the adjacent point light source by a difference method. Under certain specified conditions, the difference between adjacent object points becomes constant, so the distance is obtained by only an additions. Experimental results showed that the proposed method is more effective than the polygon-based method with FFT when the number of polygons composing an objects are high.

Computer-generated hologram of actual objects from arbitrary viewpoints with range sensors and digital cameras
Keigo Tai, Tsubasa Ichikawa, Yuji Sakamoto
PRACTICAL HOLOGRAPHY XXVIII: MATERIALS AND APPLICATIONS, 9006, SPIE-INT SOC OPTICAL ENGINEERING, 2014, [Peer-reviewed]
English, International conference proceedings, In computer-generated holograms (CGHs), various methods to generate holograms of actual objects have been proposed. One method uses the 3D information of actual objects obtained by one range sensor to generate a hologram. However, this method is unable to express occlusion because the 3D information is measured from only one viewpoint. Therefor, re-capturing 3D information is necessary to make CGHs from another viewpoint in this method. To overcome these problems, we have proposed a method that generates models of actual objects in a computer using two or more range sensors. In this method, CGHs are calculated by using multi-view images (MVIs) rendered from object models, which enables the occlusion to be expressed correctly. However, determination brightness values is unable to be performed on the whole object model because the luminance images are insufficient. This makes it difficult to generate CGHs from arbitrary viewpoints at one time. In this paper, we propose a method using additional digital cameras with range sensors to generate CGHs of actual objects from arbitrary viewpoints. This method determines the brightness values of the whole model using pictures taken by the additional cameras. The proposed method is advantageous in that re-capturing 3D information is unnecessary when CGHs are generated from another viewpoint. This method calculates CGHs with MVIs rendered from the model having brightness values. Results of computer simulations and optical reconstruction showed that it was possible to generate CGHs of actual objects with occlusion from arbitrary viewpoints.

CGH calculation with the ray tracing method for the Fourier transform optical system
Tsubasa Ichikawa, Takuo Yoneyama, Yuji Sakamoto
OPTICS EXPRESS, 21, 26, 32019, 32031, OPTICAL SOC AMER, Dec. 2013
English, Scientific journal, Computer-generated holograms (CGHs) are usually displayed on electronic devices. However, the resolution of current output devices is not high enough to display CGHs, so the visual field is very narrow. A method using a Fourier transform optical system has been proposed, to enlarge the size of reconstructed images. This paper describes a method of CGH calculations for the Fourier transform optical system to enlarge the visual field and reconstruct realistic images by using the ray tracing method. This method reconstructs images at arbitrary depths and also eliminates unnecessary light including zero-th order light. (C) 2013 Optical Society of America

Automatic Generation Method of Three Dimensional Models for Walk-through into Paintings
Fukuta Yasunori, Yamamoto Kaoru, Sakamoto Yuji
The Journal of the Institute of Image Electronics Engineers of Japan, 42, 3, 358, 366, The Institute of Image Electronics Engineers of Japan, Mar. 2013
Japanese, Scientific journal, "Tour Into the Picture (TIP)" is one of image-based rendering methods for walk-through from a single image. A problem of TIP is that it cannot be applied when the movement of viewpoint is large because foreground objects are at plates. To solve the problem, this paper proposes a method to generate three dimensional models of foreground objects. The method is based on sweep method, and generates the models with bumpy surface by using Fractal algorithm. Comparisons with manually-produced three dimensional models show that the proposed method takes a shorter time to generate the models. Moreover, subjective evaluation experiments show that the method generates natural three dimensional models appropriate for the foreground object image.

Method for computer-generating holograms from a small number of multi-view images captured under natural light
Yasuhiro Honda, Yusuke Ohsawa, Yuji Sakamoto
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers, 67, 4, J134, J141, 2013
Japanese, Scientific journal, Holography is an ideal 3D display technique that displays beautiful 3D images. However, it presents some difficulties, one of which is how to capture images under natural light. The holographic stereogram solves this problem, but it requires a large number of pictures that are captured from various directions with narrow durations. Therefore, this paper proposes a new capturing method that uses a small number of multi-view images and a method that creates holograms from the images. The methods are based on estimating the three-dimensional shape of the target objects and generating intermediate images. The effectiveness of the proposed methods is confirmed by computer simulations and optical experiments, which show that the reconstructed images are the same quality as holographic stereograms.

Computer-generated holograms using multiview images captured by a small number of sparsely arranged cameras.
Ohsawa Y, Yamaguchi K, Ichikawa T, Sakamoto Y
Applied optics, 52, 1, A167, A176, 1, Jan. 2013

Realistic expression for full-parallax computer-generated holograms with the ray-tracing method.
Ichikawa T, Yamaguchi K, Sakamoto Y
Applied optics, 52, 1, A201, A209, 1, Jan. 2013, [Peer-reviewed]

Precalculation method using spherical basic object light for computer-generated hologram.
Hosoyachi K, Yamaguchi K, Ichikawa T, Sakamoto Y
Applied optics, 52, 1, A33, A44, 1, Jan. 2013, [Peer-reviewed]

Computer-generated holograms using multiview images captured by a small number of sparsely arranged cameras
Yusuke Ohsawa, Kazuhiro Yamaguchi, Tsubasa Ichikawa, Yuji Sakamoto
Applied Optics, 52, 1, A167, A176, OSA - The Optical Society, 01 Jan. 2013, [Peer-reviewed]
English, International conference proceedings, Computer-generated holograms (CGHs) using multiview images (MVIs) are holograms generated with multiple ordinary cameras. This process typically requires a huge number of cameras arranged at high density. In this paper, we propose a method to improve CGH using MVIs that obtains the MVIs by using voxel models rather than cameras. In the proposed method the voxel model is generated using the shape-from-silhouette (SFS) technique. We perform SFS using a small number of cameras arranged sparsely to create voxel models of objects and then generate the required number of images from these models by volume rendering. This enables us to generate CGHs using MVIs with just a small number of sparsely arranged cameras. Moreover, the proposed method arrange CGHs using MVIs at arbitrary positions. © 2012 Optical Society of America.

Precalculation method using spherical basic object light for computer-generated hologram
Kohei Hosoyachi, Kazuhiro Yamaguchi, Tsubasa Ichikawa, Yuji Sakamoto
APPLIED OPTICS, 52, 1, A33, A44, OPTICAL SOC AMER, Jan. 2013, [Peer-reviewed]
English, Scientific journal, Precalculation methods for computer-generated holograms provide fast calculation by transforming precalculated object light in accordance with the subject shape in the spatial domain. In this paper, a novel method is proposed that uses precalculated object light recorded on a spherical surface, which makes the data size half that of the conventional method. Moreover, representations of the transforms by homogeneous coordinates on the spherical surface are discussed. These representations allow common operations of transforms and solve the calculation complexity that conventional precalculation methods have. The effectiveness of the proposed method was confirmed by optical image-reconstruction experiments successfully. (c) 2012 Optical Society of America

Realistic 3D image reconstruction in CGH with Fourier transform optical system
Tsubasa Ichikawa, Kazuhiro Yamaguchi, Yuji Sakamoto
PRACTICAL HOLOGRAPHY XXVII: MATERIALS AND APPLICATIONS, 8644, SPIE-INT SOC OPTICAL ENGINEERING, 2013, [Peer-reviewed]
English, International conference proceedings, In CGH, peculiar rendering techniques are necessary to express realistic 3D images because CGHs have parallax. We have proposed the calculation method with the ray tracing method that expresses the hidden surface removal, shading and so on. However, resolutions of current output devices are not high enough to display CGH, so the size of reconstructed images is restricted and viewing zone and visual field are very narrow. To enlarge the size of reconstructed images, the Fourier transform optical system is used. Then we introduce the technique to apply calculation method of CGH with ray tracing method to the Fourier transform optical system in this paper. The Fourier transform optical system reverses the depth of images and reconstructs pseudo stereoscopic 3D images in front of a hologram. We solved this problem by reconstructing images at the back of hologram plane and observing conjugate images. Moreover, we conducted elimination of unnecessary light including 0-th order light. We conducted optical reconstructions that show proposed method is able to make realistic CGHs implementing the hidden surface removal in the Fourier transform optical system.

Realistic expression for full-parallax computer-generated holograms with the ray-tracing method
Tsubasa Ichikawa, Kazuhiro Yamaguchi, Yuji Sakamoto
APPLIED OPTICS, 52, 1, A201, A209, OPTICAL SOC AMER, Jan. 2013, [Peer-reviewed]
English, Scientific journal, This paper presents a calculation method of computer-generated holograms that involves removing the hidden surface and provides realistic rendering. The method was based on the ray-tracing method that simulates rays traveling paths. Rays are cast from every elementary hologram into virtual objects and then the traveling paths of the rays are determined. Since the method is considering intersection with objects, absorption, reflection, and refraction, the method is capable of rendering realistic images. Multiple reflections and refraction are expressed by casting additional rays into the reflection direction and the transmission direction and calculating the length of the light path. To express the quality of materials, the Phong reflection model and Cook-Torrance reflection model were used. Results of optical reconstructions show that the hidden surface removal was conducted. Moreover, the texture of material appeared as well as other effects by the proposed method. (C) 2012 Optical Society of America

Calculation method of CGH for Binocular Eyepiece-Type Electro Holograph
Chanyoung Yang, Takuo Yoneyama, Yuji Sakamoto, Fumio Okuyama
9TH INTERNATIONAL SYMPOSIUM ON DISPLAY HOLOGRAPHY (ISDH 2012), 415, IOP PUBLISHING LTD, 2013, [Peer-reviewed]
English, International conference proceedings, We had researched about eyepiece-type electro holography to display 3-D images of larger objects at wider angle. We had enlarged visual field considering depth of object with Fourier optical system using two lenses. In this paper, we extend our system for binocular. In the binocular system, we use two different holograms for each eye. The 3-D image for left eye should be observed like the real object observed using left eye and the same for right eye. So, we propose a method of calculation of computer-generated hologram (CGH) transforming the coordinate system of the model data to make two holograms for binocular eyepiece-type electro holography. The coordinate system of original model data is called the world coordinate system. The left and the right coordinate system are transformed from the world coordinate system. We also propose the method for correcting the installation error that occurs when placing the electronic and optical devices. The installation error is calculated and the model data is corrected using the distance between measured position and setup position of the reconstructed image Optical reconstruction experiments were carried out to verify the proposed method.

Model generation for Japanese ivy by using growth simulation and considering phototropism and wall materials
Ari Shindo, Yasunori Fukuta, Yuji Sakamoto
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers, 66, 12, J516, J523, 2012, [Peer-reviewed]
Japanese, Scientific journal, Japanese ivy is receiving attention as green walls for solving the urban heat-island effect. Computer graphics are very useful for the evaluating the landscape of buildings covered by ivy, and thus, methods for creating computer-graphics models for climbing plants have been proposed. However, they have problems such as crowded branches and the ivy attaching to window glass, which are different from the actual growth of ivy. In this paper, a novel growth model is proposed that includes the effects of phototropism and the attachment strength by considering the material of walls. The method generates models of Japanese ivy that covers buildings, and it improves the density of the leaves and branches and represent growth around windows. The results of simulations with the proposed method showed that the method offers a more realistic landscape simulation of Japanese ivy covering buildings compared with the conventional method. © 2012.

Full parallax Computer Generated Hologram using GPU-accelerated ray tracing method
Tsubasa Ichikawa, Yuji Sakamoto
PRACTICAL HOLOGRAPHY XXVI: MATERIALS AND APPLICATIONS, 8281, SPIE-INT SOC OPTICAL ENGINEERING, 2012, [Peer-reviewed]
English, International conference proceedings, In Computer Generated Hologram (CGH), the hidden surface removal is needed to display 3D objects. Some methods of the hidden surface removal for a CGH have been proposed. However, these methods are unsuitable to make realistic images that have the complicated reflection, refraction and shadowing. We propose a calculation method of CGH using the ray tracing method. In the ray tracing method, complicated descriptions are expressed with a simple algorithm. The ray tracing method is avoided ever in CGH having a very high resolution because of enormous calculation cost. In order to speed up, we attained improvement of the calculation time using a graphics processing unit (GPU). The ray tracing from one viewpoint is unable to express full parallax CGHs. In this study, a hologram plane is divided into elementary holograms, and the center of each elementary hologram is made the starting point of the ray. Then, sets of point light every elementary hologram are constructed by the ray tracing method. As a result of optical reconstruction, it was confirmed that hidden surface removal was conducted when plural objects were in one scene. Moreover the texture of material and shadows by a front object were expressed.

Enlargement of Visual Field Considering Depth of Object for Eyepiece-Type Electro Holography
Chanyoung Yang, Yuji Sakamoto, Fumio Okuyama
PRACTICAL HOLOGRAPHY XXVI: MATERIALS AND APPLICATIONS, 8281, SPIE-INT SOC OPTICAL ENGINEERING, 2012, [Peer-reviewed]
English, International conference proceedings, In this paper, we propose a method of enlarging the visual field for displaying 3-D images of larger objects at wide angles. We also theoretically derived a maximum border for the visual field. Because its viewing zone is close to the lens, we called our method eyepiece-type electro holography. By placing a real image within the focal point of a convex lens, we obtain a 3-D image of the object as a virtual image behind the lens. The range of visual field in this case starts on the lens, continues to infinity on the z-axis, and shapes a truncated cone.

Calculation method for computer-generated holograms considering various reflectance distributions based on microfacets with various surface roughnesses
YAMAGUCHI Kazuhiro, ICHIKAWA Tsubasa, SAKAMOTO Yuji
Appl Opt, 50, 34, H195, 01 Dec. 2011
English

Calculation method of reflectance distributions for computer-generated holograms using the finite-difference time-domain method
ICHIKAWA Tsubasa, SAKAMOTO Yuji, SUBAGYO Agus, SUEOKA Kazuhisa
Appl Opt, 50, 34, H211, 01 Dec. 2011
English

Calculation method for computer-generated holograms with cylindrical basic object light by using a graphics processing unit
SAKATA Hironobu, HOSOYACHI Kouhei, YANG Chan-young, SAKAMOTO Yuji
Appl Opt, 50, 34, H306, H314, Optical Society of America, 01 Dec. 2011
English, It takes an enormous amount of time to calculate a computer-generated hologram (CGH). A fast calculation method for a CGH using precalculated object light has been proposed in which the light waves of an arbitrary object are calculated using transform calculations of the precalculated object light. However, this method requires a huge amount of memory. This paper proposes the use of a method that uses a cylindrical basic object light to reduce the memory requirement. Furthermore, it is accelerated by using a graphics processing unit (GPU). Experimental results show that the calculation speed on a GPU is about 65 times faster than that on a CPU. (C) 2011 Optical Society of America

Calculation method of reflectance distributions for computer-generated holograms using the finite-difference time-domain method
Tsubasa Ichikawa, Yuji Sakamoto, Agus Subagyo, Kazuhisa Sueoka
APPLIED OPTICS, 50, 34, H211, H219, OPTICAL SOC AMER, Dec. 2011, [Peer-reviewed]
English, Scientific journal, The research on reflectance distributions in computer-generated holograms (CGHs) is particularly sparse, and the textures of materials are not expressed. Thus, we propose a method for calculating reflectance distributions in CGHs that uses the finite-difference time-domain method. In this method, reflected light from an uneven surface made on a computer is analyzed by finite-difference time-domain simulation, and the reflected light distribution is applied to the CGH as an object light. We report the relations between the surface roughness of the objects and the reflectance distributions, and show that the reflectance distributions are given to CGHs by imaging simulation. (C) 2011 Optical Society of America

Calculation method for computer-generated holograms considering various reflectance distributions based on microfacets with various surface roughnesses
Kazuhiro Yamaguchi, Tsubasa Ichikawa, Yuji Sakamoto
APPLIED OPTICS, 50, 34, H195, H202, OPTICAL SOC AMER, Dec. 2011, [Peer-reviewed]
English, Scientific journal, Computer-generated holograms are generated by three-dimensional technology, and they can be used to reconstruct natural and virtual objects by simulating light waves based on holography. This research was an improvement on previous work that took into consideration reflectance distributions from the various roughnesses of objects. The previous work generated roughness by using a simple model, so that only simple roughness was generated. The proposed method generated more complex roughness than that in the previous work, and the influence of roughness on the reflectance distributions was investigated. Computer simulations, which were compared with the reflectance distributions from the various roughnesses, were carried out. Moreover, computational and optical reconstructions were carried out as examples of reconstructions. As a result of the experiments, we confirmed that the various roughnesses actually influenced the reflectance distributions. (C) 2011 Optical Society of America

Calculation method for CGH considering smooth shading with polygon models
Kazuhiro Yamaguchi, Tsubasa Ichikawa, Yuji Sakamoto
PRACTICAL HOLOGRAPHY XXV: MATERIALS AND APPLICATIONS, 7957, SPIE-INT SOC OPTICAL ENGINEERING, 2011, [Peer-reviewed]
English, International conference proceedings, Computer generated hologram (CGH) is a type of 3D display technology that displays 3D scenes. It generates hologram data by simulating the light waves of the recording processes of optical holography such as reflections, diffractions, propagations, and interferences in computers. Holograms are generated by out-putting hologram data to certain devices. The holograms reconstruct natural 3D objects as well as does optical holography. Moreover, virtual objects created by the computer can be reconstructed.
However, there are many problems in realizing a 3D display based on CGH. In particular, improving the reality of reconstructed images is a serious issue. To improve reality, we have studied rendering technologies for CGH such as reflectance distributions.(1) By taking into consideration reflectance distributions for CGH, images with various luminance can be reconstructed. However, the previous work was used to generate hologram data by using only 2D objects. To reconstruct complex objects of high realty, the reconstruction of 3D objects with reflectance distributions is necessary. To solve this problem, polygon models can be used to reconstruct 3D objects.(2,3) The polygon model of the object is divided into many planar polygons. However, to reconstruct curved surfaces, many polygons are required.

Quantitative quality measure based on light wave distribution to access 3D display
Yuji Sakamoto, Fumio Okuyama
PRACTICAL HOLOGRAPHY XXV: MATERIALS AND APPLICATIONS, 7957, SPIE-INT SOC OPTICAL ENGINEERING, 2011, [Peer-reviewed]
English, International conference proceedings, There are a lot of three-dimensional (3D) displaying methods such as stereoscopy, integral photography, holography, etc. These technologies have different 3D vision properties and 3D image qualities. Conventionally, biological responsiveness is measured by using an actual 3D display in order to evaluate image qualities of 3D displaying method. It is required quantitative quality measure for 3D images for quantitative evaluation, which are useful for comparing 3D image quality and a design of a new display system. In this paper, we propose quality measures for 3D images named volume signal to noise ratio (VSNR), which is a three-dimensionally extended signal to noise ratio (SNR). A 3D display produces light wave distributions in 3D space, which makes observers view 3D image illusions. The VSNR measures error of light wave distributions between generated by actual objects and produced by a 3D display. The light wave distribution is including various factors for 3D perception of human such as resolution of reconstructed images, visual fields, motion parallax, and depth of field. The VSNR evaluates these 3D perception factors totally. We were carried out the experiments to certificate the efficiency of the VSNR. 3D images represented electro-holographic display and integral photographic displays were evaluated by the VSNR. The results indicated that the electro-holographic display has better quality than integral photographic display, but speckle noise deteriorates the 3D image quality.

A method of Calculating Reflectance Distributions for CGH with FDTD using the Structure of Actual Surfaces
Ichikawa Tsubasa, Sakamoto Yuji, Subagyo Agus, Sueoka Kazuhisa
PRACTICAL HOLOGRAPHY XXV: MATERIALS AND APPLICATIONS, 7957, 2011, [Peer-reviewed]

Computer-generated holograms considering background reflection on various object shapes with reflectance distributions
Kazuhiro Yamaguchi, Yuji Sakamoto
PRACTICAL HOLOGRAPHY XXIV: MATERIALS AND APPLICATIONS, 7619, SPIE-INT SOC OPTICAL ENGINEERING, 2010, [Peer-reviewed]
English, International conference proceedings, Computer-generated hologram (CGH) is a one of 3-D display technologies, and it reconstructs natural and virtual objects. However, improvement of the reality of reconstructed images is necessary for reconstructing complex and clear scenes like computer graphics. We have studied about the rendering techniques for CGH, and proposed the method considering background reflections and reflectance distributions. The background reflections and reflectance distributions are the characteristics of reflection. Metallic objects and reflected scenes were reconstructed by considering these. In this paper, we improved the previous works for express complex scenes. The proposed method considered the background reflections and reflectance distributions on the curved surface such as convex and concave mirrors. By using the phase transformation, the background reflections and reflectance distributions on it with some roughness are generated. We performed that the background reflections and reflectance distributions on the convex and concave mirrors with roughness are actually obtained through computational and optical reconstructions.

Calculation method using a set of microfacets for computer-generated hologram considering reflectance distributions
Kazuhiro Yamaguchi, Yuji Sakamoto
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers, 63, 12, 1846, 1852, The Institute of Image Information and Television Engineers, Dec. 2009
Japanese, Scientific journal, Computer-generated hologram (CGH) is a technology that makes hologram data using a simulation of the recording process of holography. However, there are still many problems with CGH. We describe a calculation method that takes into consideration the reflectance distribution of object surfaces for CGH to improve the reality of reconstructed images. This method is based on the Blinn, or the Torrance-Sparrow, reflection models in CG. In these models, object surfaces are divided into a set of mirror-like microfacets. By calculating the phase differences of object surfaces with these models, various reflectance distributions for CGH are expressed. We did computer-simulated experiments, which compared the light intensity distribution of simulated values on each reflectance factor. We also did optical reconstruction experiments. These experiments showed that the proposed method makes various reflectance distributions of reconstructed images.

Computer generated hologram with characteristics of reflection: reflectance distributions and reflected images
YAMAGUCHI Kazuhiro, SAKAMOTO Yuji
Appl Opt, 48, 34, H203, 01 Dec. 2009
English

Fast computation method for a Fresnel hologram using three-dimensional affine transformations in real space
SAKATA Hironobu, SAKAMOTO Yuji
Appl Opt, 48, 34, H212, H221, Optical Society of America, 01 Dec. 2009
English, Calculating computer-generated holograms takes a tremendous amount of computation time. We propose a fast method for calculating object lights for Fresnel holograms without the use of a Fourier transform. This method generates object lights of variously shaped patches from a basic object light for a fixed-shape patch by using three-dimensional affine transforms. It can thus calculate holograms that display complex objects including patches of various shapes. Computer simulations and optical experiments demonstrate the effectiveness of this method. The results show that it performs twice as fast as a method that uses a Fourier transform.© 2009 Optical Society of America

Computer generated hologram with characteristics of reflection: reflectance distributions and reflected images
Kazuhiro Yamaguchi, Yuji Sakamoto
APPLIED OPTICS, 48, 34, H203, H211, OPTICAL SOC AMER, Dec. 2009, [Peer-reviewed]
English, Scientific journal, This paper proposes a new computer generated hologram (CGH) method that considers the reflectance distribution on object surfaces and reflected images. The reflectance distributions are generated from phase differences determined by the shape of the object surface, which is constructed by using the Blinn and Torrance-Sparrow reflection models. Moreover, the reflected images are adapted when they are mapped onto metallic objects such as mirrors. Incorporating these two characteristics of reflection means that CGHs can express metallic objects realistically. Computer simulations and computational and optical reconstructed experiments were carried out. These results show the potential of the proposed method for showing metallic objects. (C) 2009 Optical Society of America

9-10 Effect of Element Shape Using Active Contour Model with Structuring Elements
Mikami Hirosato, Sakamoto Yuji
PROCEEDINGS OF THE ITE WINTER ANNUAL CONVENTION, 2009, _9, 10-1_, The Institute of Image Information and Television Engineers, 2009
Japanese, We have proposed the contour extraction method using Active Contour Model with Structuring Elements. The results of contour extraction are influenced from the shape of structuring elements. We applied the method into the extractions of retina layers from OCT, and evaluated the effects of Element shape using Active Contour Model with Structuring Elements.

Calculation method considering the reflectance distribution for metallic objects in CGH
Kazuhiro Yamaguchi, Yuji Sakamoto
PRACTICAL HOLOGRAPHY XXIII: MATERIALS AND APPLICATIONS, 7233, SPIE-INT SOC OPTICAL ENGINEERING, 2009, [Peer-reviewed]
English, International conference proceedings, We propose a new method calculating the reflectance distribution on object surfaces for computer-generated holograms to improve the reality of reconstructed images, which take into consideration reflection on the surfaces of metallic objects. It is based on the Blinn or the Torrance-Sparrow reflection model that has been established in computer graphics. Moreover, we also take into account the Fresnel equation for the method, which provides the degree of reflection on metallic surface. We adapted this model to the process of calculating computer-generated holograms, so that various reflectance distributions could be derived. In our experiments, we carried out comparison theoretical and simulated intensity distributions, optical reconstructed experiments, and computer simulations. As a result, we obtained the reflectance distributions of reconstructed images by using the new approach.

High luminance of grating images using photopic luminous efficiency function
Hiroyuki Asano, Yuji Sakamoto
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers, 61, 4, 514, 517, Inst. of Image Information and Television Engineers, 2007
Japanese, Scientific journal, For conventional grating images, high luminance of reproduction images is required. In color representation of conventional grating images, red, green and blue spectra are fixed. We propose a color representation method for grating images that uses [the two brightest spectra for the human optical system? (This may need some rewording. I am not sure what you want tosay here, but this is one possibility.)] To verify the method, we used theoretical analysis and experiments. The results show that a reconstructed image using our method is 1.2 times brighter than that using the conventional RGB method.

A Representation Method for Object Surface Glossiness in Computer-Generated Hologram
SAKAMOTO YUJI, TSURUNO ATSUSHI
電子情報通信学会論文誌 D-2, J88-D-2, 10, 2046, 2053, The Institute of Electronics, Information and Communication Engineers, 01 Oct. 2005
Japanese, 計算機合成ホログラムは, 立体像を直接観察することのできる三次元ディスプレイとして期待される方式であるが, リアリティの高い立体像を表示するのに必要となるレンダリング技術に関しては, 研究が進んでいない. 本論文では, 計算機合成ホログラムの再生像の物体表面に光沢を与える新たな計算方法を提案する. この方法は, 光の伝搬の計算において物体表面の反射特性を考慮するもので, 従来の手法に比べ, 様々な反射特性を表現することができる. 更に, この提案法にCook-Torannce反射モデルを適応し, 金属光沢の付与法を提案する. また, 光学再生実験を行い金属特有の色や反射特性が表現されていることを明らかにした.

Conjugate image elimination by spatial frequency filtering in computer generated holograms
Yuji Sakamoto
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers, 59, 4, 588, 591, Inst. of Image Information and Television Engineers, 2005
Japanese, Scientific journal, We propose a conjugate image elimination method for computer generated holograms by spatial frequency filtering. The method, a hologram-data calculation algorithm, does not require special optical equipment. Moreover, any object modeling or object light calculation method can be used.

Calculation Method of Computer Generation Hologram Considering Refraction
KANAZAWA YOSHIAKI, SAKAMOTO YUJI, AOKI YOSHINAO
電子情報通信学会論文誌 D-2, J88-D-2, 1, 88, 94, The Institute of Electronics, Information and Communication Engineers, 01 Jan. 2005
Japanese, 計算機合成ホログラムは,立体像を直接観察することのできる三次元ディスプレイとして期待される方式である.しかし,リアリティの高い立体像を表示するのに必要となるレンダリング技術に関しては,コンピュータグラフィックスなどに比べ,著しく研究が進んでいない.特に,光が透明な物体を透過する際に発生する屈折現象の表現に関しては,研究がなされていない.そこで,本論文ではこの屈折現象を考慮した計算機合成ホログラムの計算法を提案する.提案法は,立体的な物体のホログラムを計算するのに用いられている断暦法をもとに,屈折率を考慮したものである.これに,光・電波の解析に用いられるFD-BPM (Finite Difference Beam Propagation Method)法を適応することにより,高速な計算法を実現した.この計算法を用いてホログラムを作成,光学像再生を行い,提案法が計算機合成ホログラムで屈折現象をもつ立体物体の表示に有効であることを確認した.

A CD-R system for recording computer-generated holograms
Yuji Sakamoto, Morito Morishima, Akira Usui
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers, 58, 4, 549, 554, Inst. of Image Information and Television Engineers, 2004
Japanese, Scientific journal, To display 3D images on a computer-generated hologram, you need to have a very high resolution hologram-recording system. We developed a CD-R (Compact Disk-Recordable) drive to record CGH data on CD-R disks, that have a high resolution and a dot size of 1.5μm. By using this drive, it is possible to make holograms inexpensively in a short-time without the need for special environments, such as dark rooms, clean rooms, etc. The drive realizes desktop holograming that can handle all CGH process including model making, hologram calculations, and hologram recordings on a personal computer. In this paper, we describe the system and discuss the hologram-calculation method adapted for CD-R disks.

Autostereoscopic Visualization of Volume Data Using by Computer-Generated Hologram.
SAKAMOTO YUJI, AOKI YOSHINAO
電子情報通信学会論文誌 D-2, J86-D-2, 2, 302, 309, The Institute of Electronics, Information and Communication Engineers, 01 Feb. 2003
Japanese, CT (Computer Tomgraphy)やMRI (Magnetic Resonance Imaging),3次元レーダなどによって得られる3次元データ(ボリュームデータ)を人間に理解しやすく提示する方法が求められている.立体ディスプレイによるこれらのデータの表示は,直接,立体像を人間に提示するものであり,立体構造の認識に適している.特に,ホログラフィ技術による立体表示は,人間の立体認識を満足させる優れたものである.本研究では,計算機合成ホログラム(Computer generated hologram)技術を用いて,中間的な画像や写真技術を用いずに,ボリュームデータから直接ホログラムを求めるボリュームレンダリングCGH法を提案する.この方法では,計算によってホログラムを求めるため立体像の表示の柔軟性が高く,陰影付けが可能であるほか,ボリュームデータを表面のみの内部の不透明な表示から,内部構造も見ることのできる透明な表示まで,様々な立体表示が可能である.医療用3次元MRIデータより,本提案法を用いて計算機合成ホログラムを作製し,光学実験によりその有効性を確認した.

A fast computation method of hidden surface removal for computer-generated holograms using Z-buffer considering ray arrival direction
Masafumi Takase, Yuji Sakamoto, Yoshinao Aoki
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers, 57, 4, 483, 489, Inst. of Image Information and Television Engineers, 2003
Japanese, Scientific journal, A computer-generated hologram (CGH) is an autostereoscopic method for displaying images without the need for special glasses. To achieve realistic 3D displays using a CGH, hidden surface removal is a key technique for displaying multiple 3D objects. However, an established method for object-light calculation considering hidden surface removal is currently not available. We describe a new algorithm considering hidden surface removal using a Z-buffer that has information for ray arrival direction. The method can display multiple-view-point 3D images and compute object light faster than the conventional method. The results of optical experiments using holograms generated by the method show us 3D images with hidden surface removal.

An Algorithm of Hidden Surface Removal Using Shadow-Propagation Method for Computer-Generated Hologram.
SAKAMOTO YUJI
電子情報通信学会論文誌 D-2, J85-D-2, 12, 1832, 1839, The Institute of Electronics, Information and Communication Engineers, 01 Dec. 2002
Japanese

A Fast Computational Method for Computer Generated Fourier Hologram Using Patch Model.
SAKAMOTO YUJI, NAGAO TOMOHIRO
電子情報通信学会論文誌 C, J85-C, 3, 150, 157, The Institute of Electronics, Information and Communication Engineers, 01 Mar. 2002
Japanese, 計算機合成ホログラフィ(Computer Generated Holography)は,計算機内の仮想的な物体から立体像を表示する技術であり,立体的な視覚特性を満たす表示方式として注目されている.しかし,ホログラムを作成するのに必要な光の伝搬計算に膨大な時間がかかる問題点があった.本論文では,物体のモデリング手法として,物体を基本的な図形によって定義するパッチモデルを用い,このモデルよりの高速なホログラム計算法を提案する.更に,計算機シミュレーションによりアルゴリズムの検証を行うとともに,本提案法を用いて作成したホログラムによる光学実験結果を報告する.

An algorithm for object-light calculation considering reflectance distribution for computer-generated holograms
Yuji Sakamoto, Yutaka Yamashita, Tomohiro Nagao
Kyokai Joho Imeji Zasshi/Journal of the Institute of Image Information and Television Engineers, 56, 4, 611, 616, Inst. of Image Information and Television Engineers, 2002
Japanese, Scientific journal, To achieve realistic 3D displays using by computer-generated holograms, both modeling and rendering methods are key techniques. In this paper, we propose a new algorithm for object-light calculation considering reflectance distribution, which is based on fast processing of spatial frequency. The method is applied to Phong's reflection model, which is a well-known model in computer graphics. The results of optical experiments show that the method can be successfully applied to computer-generated holograms.

Creating and Reconstructing Methods of a Virtual Object Model Based on Volume Data for Deformation.
KATO MANABU, SAKAMOTO YUJI, TAKAHASHI KOTAKU
電子情報通信学会論文誌 D-2, J83-D-2, 12, 2822, 2829, The Institute of Electronics, Information and Communication Engineers, 25 Dec. 2000
Japanese, 近年のコンピュータの処理能力向上により, 人工現実感中での仮想物体を対象とした, ばねモデルによる変形操作の研究が行われるようになってきた.これらの研究は様々な分野への応用が期待されるが, 医療分野では手術シミュレーションへの応用が考えられている.手術シミュレーションにおいては, 内臓や筋肉などの粘弾性をもつ物体の変形を表現する必要があり, そのための多くの研究がなされてきたが, それらの多くは変形処理に重点がおかれ, CT画像などの個人データをもとにしたモデル化の手法については十分な検討がなされていなかった.また, 切断を考慮したモデル化が行われていないために, 切断の表現が困難であるという問題もあった.そこで, 自然な切断が可能であり, 更に個人データを反映させることの可能なモデル化を目的とし, 実際のCT画像などから作成されるボリュームデータに基づいたばねモデルの自動生成法と, 変形結果を再びボリュームデータとして出力するための再構成法について提案を行う.提案するばねモデル生成法とボリュームデータへの再構成法を適用したシステムを作成し, 物体の変形操作の実験を行うことで, その有効性を確認した.

Development of a CGH Watermarking Method using Character Coding for Transmission with a Communications Satellite
TANG Weili, AOKI Yoshinao, SAKAMOTO Yuji
The transactions of the Institute of Electronics, Information and Communication Engineers. B, 83, 8, 1101, 1113, The Institute of Electronics, Information and Communication Engineers, 20 Aug. 2000
Japanese, 計算ホログラム(CGH)の技法を応用した電子透かし法における新しい文字コーディング法を開発した.この手法では, CGH面のサンプル点の強度を文字パターンで表示するところに特徴がある.通信には原画像に文字パターンによる透かしを加え, 画像データをパケットとして伝送する.また, ホログラムの振幅情報と位相情報により両者の関係情報を抽出用の中間情報として作っておく.受信したデータ(文字パターン)から振幅情報を復元し, この振幅情報と中間情報を利用し, 位相情報を復元する.更に, CGHの技法により再生像を生成する.また, 文字パターンの回復率を向上させるため, 文字パターン面のサイズを原画像の1/4にして, 同じパターンを四つ配置する方法を新たに提案した.本手法では, パケットの損失があっても, 文字パターンの特性を利用し, 損失を減少させることが可能てなる.またCGHの特徴によっても, 一部分のデータが欠損しても, 認証用の画像を再生できるという利点をもっている.更に, 本論文は, 衛星通信の予備実験として, 自局折返しによる伝送実験を行い, 効果を確認した.また, 各攻撃方法の効果をシミュレーションで示した.

Ballistocardiogram of avian eggs determined by an electromagnetic induction coil
H. Ono, R. Akiyama, Y. Sakamoto, J. T. Pearson, H. Tazawa
Medical and Biological Engineering and Computing, 35, 4, 431, 435, Peter Peregrinus Ltd, Jul. 1997, [Peer-reviewed]
English, Scientific journal, As an avian embryo grows within an eggshell, the whole egg is moved by embryonic activity and also by the embryonic heartbeat. A technical interest in detecting minute biological movements has prompted the development of techniques and systems to measure the cardiogenic ballistic movement of the egg or ballistocardiogram. (BCG). In this context, there is interest in using an electromagnetic induction coil (solenoid) as another simple sensor to measure the BCG and examining its possibility for BCG measurement. A small permanent magnet is attached tightly to the surface of an incubated egg, and then the egg with the magnet is placed in a solenoid. Preliminary model analysis is made to design a setup of the egg, magnet and solenoid coupling system. Then, simultaneous measurement with a laser displacement measuring system, developed previously, is made for chicken eggs, indicating that the solenoid detects the minute cardiogenic ballistic movements and that the BCG determined is a measure of the velocity of egg movements.

An Automatic Extraction Method for Internal Part of Organs from MR Images Featuring Variable Sizes of Texture Region.
KAWAHARA TOSHIKAZU, SAKAMOTO YUJI, ZANA M
電子情報通信学会論文誌 D-2, J80-D-2, 7, 1651, 1658, Jul. 1997
Japanese

Charactaristics of Indoor Radio Propagation in 2.5GHz Band by Movement of Men in Rooms.
SAKIMOTO YUJI, TAMURA AKIYOSHI, HATA YOSHIYUKI
電子情報通信学会論文誌 B-2, 79, 2, 110, 116, The Institute of Electronics, Information and Communication Engineers, Feb. 1996
Japanese, 近年,無線LANやコンビニエンスフォン, PHS (Personal Handy-Phone System)等の屋内での利用が想定される通信システムが実用化されている. これらのシステムにおいて,屋内の電波伝搬は,基地局の配置やプロトコルの選択等の設計において重要な問題となる.しかし,屋内の伝搬特性は不明な点も多く,今後の研究が期待されている.伝搬特性には空間的な特性と時間的な特性があり,屋内伝搬においでは送受信アンテナともに固定されていても変動(フェージング)が存在し, この原因は人間の移動によるものであることが知られている.本論文では人間の移動が時間変動に与える影響を測定し, この結果を報告する.また,その統計的な性質について議論し,屋外移動通信で用いられているフェージングモデルとの相違を明らかにする.

2-DIMENSIONAL CARDIOGENIC BALLISTIC MOVEMENTS OF AVIAN EGGS
Y SAKAMOTO, MA HAQUE, H ONO, J PEARSON, H TAZAWA
MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING, 33, 4, 611, 614, PETER PEREGRINUS LTD, Jul. 1995, [Peer-reviewed]
English, Scientific journal

A METHOD OF RECONSTRUCTING FRONT-LOOKING RADAR USING LONG-WAVELENGTH HOLOGRAPHY
Y SAKAMOTO, Y AOKI
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS, 77, 10, 49, 59, SCRIPTA TECHNICA PUBL, Oct. 1994, [Peer-reviewed]
English, Scientific journal, When the synthetic aperture method is applied to the imaging of objects in the front direction of a moving vehicle, a problem arises in that, if the objects are at positions symmetrical to the direction of movement, the Doppler frequencies change in the same way. Consequently, ghosts symmetrical to the axis are produced in the reconstructed image. From another viewpoint, when an object exists in the direction perpendicular to the direction of movement, the change of the Doppler frequency depends on the position of the object. Then the rate of change is not kept constant and the processing based on the FFT algorithm, as in the general cases of synthetic aperture radar and long-wavelength holography, cannot be employed.
This paper proposes an imaging method for the front-looking radar based on the principle of long-wavelength holography. The proposed method can solve the ghost problem for the objects symmetrical to the direction of movement using a small number of antennas in the azimuth direction. An algorithm also is proposed for high-speed image reconstruction from the data acquired by the system. The theoretical resolution and the range of maximum possible imaging are discussed. Furthermore, the validity of the proposed method is verified by a computer simulation and an experiment using microwaves.

COMPARISONS BETWEEN INVASIVE AND NONINVASIVE DETERMINATIONS OF EMBRYONIC HEART-RATE IN CHICKENS
MA HAQUE, W WATANABE, H ONO, Y SAKAMOTO, H TAZAWA
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-PHYSIOLOGY, 108, 2-3, 221, 227, PERGAMON-ELSEVIER SCIENCE LTD, Jun. 1994, [Peer-reviewed]
English, Scientific journal, The embryonic heart rate (HR) of chicken eggs was determined by ballistocardiography, electrocardiography, impedance-cardiography and acoustocardiography. The effects of these different methods on the HR were examined for young (12-day-old) and late (16- and 18-day-old) embryos. Ballistocardiography is a non-invasive method. Nevertheless, the mean HRs determined using this method at 5-hr intervals were significantly different in many embryos. This difference was caused by the natural variability of embryonic HR. The statistical analyses indicated that any of these four methods did not influence the HR measurement and can be used as a simple means for determination of the embryonic HR.

Classification Method for Three Dimensional Images Using a Density-Gradient Histogram.
SAKAMOTO YUJI, OTSUKA AKIO, ITADA YOSHIKATSU, AOKI YOSHINAO
電子情報通信学会論文誌 D-2, 77, 4, 682, 689, The Institute of Electronics, Information and Communication Engineers, Apr. 1994
Japanese, 近年,医用や,気象,流体などの分野で,3次元の画像データの収集が行われるようになり,表示法,処理に関する研究が行われている.これらの3次元画像データの画素分類や領域分割などの処理は,パターン認識や表示法の前処理として重要である.しかし,3次元画像は一般に2次元画像に比べて分解能が低く,複雑な領域では複数のクラスが混じり合い,中間的な値をもつため,画素分類や領域分割において誤った結果をもたらす.本論文では,濃度とこう配の大きさによる2次元ヒストグラムを用いたより正確な画素分類法を提案する.この2次元ヒストグラム上では,物体の非境界部分と境界部分が分離可能であり,対象のボクセルにおいてクラスが混じり合っているかどうか識別可能である.本論文では,まず2次元ヒストグラム上での境界部分,非境界部分の分布を検討し定式化を行う.次に,これを用いて2次元ヒストグラム上の各点における各クラスへの所属値を求め,この所属値による3次元画像の画素分類方法を提案する.最後に,ファントムデータおよび医用のCT(Computed Tomography)画像の画素分類に本手法を適用した.この結果より,本手法は従来法に比べてより正確な画素分類ができるほか,3次元画像の表示法として一般的なボリュームレンダリングとも高い整合性をもつことが示された.

Gesture Description and Structure of a Dictionary for Intelligent Communication of Sigh Language Images.
TANAHASHI SHIN, SAKAMOTO YUJI, AOKI YOSHINAO
電子情報通信学会論文誌 A, 76, 9, 1332, 1341, Sep. 1993
Japanese

A Reconstruction Method of Front-Looking Radar Using Long-Wavelength Holography Technique.
SAKAMOTO YUJI, AOKI YOSHINAO
電子情報通信学会論文誌 B-2, 76, 8, 698, 705, The Institute of Electronics, Information and Communication Engineers, Aug. 1993
Japanese, 合成開口法を用いて移動体の進行方向前方の画像化を行おうとする場合,進行方向軸に対して左右対称の位置にある物体ではドップラー周波数の変化が同じになるため,再生画像に軸対称のゴーストが発生する.また進行方向に直交する方向の物体位置に,ドップラーによる周波数の変化率が依存し,変化率が一定でないため,合成開口レーダや長波長ホログラフィに一般的に用いられるFFTアルゴリズムを用いた処理を利用することができない.本研究では,長波長ホログラフィの原理を用いた前方監視レーダの画像化を提案する.ここでは,方位方向に少数のアンテナを用いることによって,進行方向軸に対称に発生するゴーストの問題を解決する方法を提案する.また,この手法によって収集されたデータより,像再生を高速に行うアルゴリズムを提案すると共に,理論的分解能と最大画像化範囲等について,検討を加える.更に,計算機シミュレーションとマイクロ波を用いた実験によって,提案手法の有効性を確かめた.

Trajectory Tracking Control for Robot Manipulators with Fuzzy Adaptation Rule
SONG Beidong, SAKAMOTO Yuji, HASHIMOTO Yukio, AOKI Yoshinao
Journal of Japan Society for Fuzzy Theory and Systems, 4, 2, 369, 378, Japan Society for Fuzzy Theory and intelligent informatics, 15 Apr. 1992
Japanese, Robot manipulators PD feedback is a PTP(Point To Point)control from which can handle nonlinearity of robot manipulators with the simple linear feedback and guarantees system stability strictly. In this paper, we propose a method of trajectory tracking control for robot manipulators with fuzzy adaptation rule based on PD feedback. The result of an experiment using a 2-degree-of-freedom manipulator shows the effectiveness of this trajectory tracking control method for robot manipulators. A advantage of this method is that control algorithm is simple and small in calculation quantity.

IMPROVEMENT OF RESOLUTION IN ACOUSTICAL HOLOGRAPHIC IMAGING BY NEURAL NETWORK PROCESSING
Y AOKI, Y SAKAMOTO, S YAMAGUCHI, R MITSUHASHI
ACOUSTICAL IMAGING, VOL 19, 19, 83, 88, PLENUM PRESS DIV PLENUM PUBLISHING CORP, 1992, [Peer-reviewed]
English, International conference proceedings

Control of an Overhead Travelling Crane System Based on the Model Reference Adaptive Control System with a Fuzzy Adaptation Rule
SONG Beidong, SAKAMOTO Yuji, HASIMOTO Yukio, AOKI Yoshinao
Journal of Japan Society for Fuzzy Theory and Systems, 3, 4, 177, 185, Japan Society for Fuzzy Theory and intelligent informatics, Apr. 1991, [Peer-reviewed]
Japanese, Scientific journal, モデル規範形適応制御系(Model Reference Adaptive Control System, MRACS)は、追従過程のオーバシュート、上昇時間、などの制御性能指標を定量的に指定することが要求されるようなサーボ系の設計に対し有効である。しかし、モデル規範適応制御系における適応則の設計においてプラントの線形モデルが必要であるので、プラントが複雑な非線形であるような場合、モデル規範形適応制御系を適用することが困難となる。この問題を解決するために、モデル規範形適応制御系の適応則の設計にファジィ推論を導入し、ファジィ適応則をもつモデル規範形適応制御系を提案した。また、それを天井クレーンの振れ止め・位置制御に応用し、天井クレーン制御におけるトロリーが終着位置に達する時間や位置のオーバシュートの制御性能指標を定量的に指定することができることを示した。エネルギに注目した制御方式を用いることによって、制御系の漸近安定性が厳密に保証することができる。さらに天井クレーン制御の模型実験結果により、ファジィ適応則をもつモデル規範形適応制御系と天井クレーン制御への応用の有効性を示した。

Display techniques of volume images of buried objects in piled snow by acoustical and microwave holographic radar
Y.Aoki, Y.Tajiri, Y.Sakamoto, M.Ikegami
Acoustical Imaging, 17, 285, 294, Plenum Press, 1989, [Peer-reviewed]
English, Scientific journal

雪中レ-ダシステムのための3次元デ-タ表示手法
高橋 佳成, 坂本 雄児, 青木 由直
電子情報通信学会論文誌. D, 情報・システム, 71, 10, p2002, 2009, 電子情報通信学会, Oct. 1988
Japanese

Three-Dimensional Imaging of Objects in Accumulated Snow Using Multifrequency Holography
Yuji Sakamoto, Katsuhiro Tajiri, Takaya Sawai, Yoshinao Aoki
IEEE Transactions on Geoscience and Remote Sensing, 26, 4, 430, 436, 1988, [Peer-reviewed]
English, Scientific journal, In this paper, we discuss the three-dimensional (3-D) imaging of objects buried in snow using multifrequency holography. The cross-sectional images obtained by radar used for target detection in soils, sand, and snow do not meet expectations in identifying the shapes of targets. We propose a 3-D imaging reconstruction technique using multifrequency holography and apply the method to recognize the shapes of the objects buried in snow. An experimental system using X-band microwaves was constructed and image reconstruction was accomplished mathematically by a computer, with the image displayed on a CRT using a specially designed circuit. Through field trials in which we were able to obtain 3-D images of metallic cylinders and a mannequin buried in snow, we concluded that the method has the potential to identify the position and shape of targets in snow. © 1988 IEEE

Detection of objects buried in snow using multi-frequency holography.
SAKAMOTO YUJI, TAJIRI KATUHIRO, SAWAI TAKAYA, AOKI YOSHINAO
電子情報通信学会論文誌 B, 70, 12, 1544, 1550, 電子情報通信学会, Dec. 1987
Japanese

Multi-frequency holography on near region using range curvature correction.
TAJIRI KATSUHIRO, SAKAMOTO YUJI, AOKI YOSHINAO
電子情報通信学会論文誌 B, 70, 3, 396, 402, 電子情報通信学会, Mar. 1987
Japanese

An under-snow radar using multi-frequency holography.
SAKAMOTO YUJI, TAKAHASHI YUKINOBU, IIJIMA YOSHIHIRO, AOKI YOSHINAO
電子通信学会論文誌 B, 68, 5, 602, 608, 電子通信学会, May 1985
Japanese

A High Embedding Capacity Watermarking Technique Based on Regularization for Convolutional Neural Network Model (ITS : Intelligent Transport Systems Technology)
何 晗, 姜 錫, 坂本 雄児, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 119, 421, 41, 46, 27 Feb. 2020
電子情報通信学会, Japanese

A High Embedding Capacity Watermarking Technique Based on Regularization for Convolutional Neural Network Model
何 晗, 姜 錫, 坂本 雄児, 映像情報メディア学会技術報告 = ITE technical report, 44, 6, 41, 46, Feb. 2020
映像情報メディア学会, Japanese

Evaluation of Image Quality for Optical Reconstructed Images in Electro-Holographic Display
山口 一弘, 坂本 雄児, 画像ラボ, 28, 11, 13, 18, Nov. 2017
日本工業出版, Japanese

Simulation of Image Reconstruction based on Point Light Source Method from Computer-Generated Hologram using Fourier Transform Optical System
水戸部 将也, 山口 一弘, 坂本 雄児, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 464, 327, 331, 20 Feb. 2017
電子情報通信学会, Japanese

Development of Holographic-Animation Generation System using Fast Calculation Method of Computer-Generated Hologram
韋 霊傑, 坂本 雄児, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 464, 333, 338, 20 Feb. 2017
電子情報通信学会, Japanese

Development of Holographic-Animation Generation System using Fast Calculation Method of Computer-Generated Hologram
韋 霊傑, 坂本 雄児, 映像情報メディア学会技術報告 = ITE technical report, 41, 5, 333, 338, Feb. 2017
映像情報メディア学会, Japanese

Simulation of Image Reconstruction based on Point Light Source Method from Computer-Generated Hologram using Fourier Transform Optical System
水戸部 将也, 山口 一弘, 坂本 雄児, 映像情報メディア学会技術報告 = ITE technical report, 41, 5, 327, 331, Feb. 2017
映像情報メディア学会, Japanese

Improvement of ROI Data Hiding Technique for Selected Region of JPEG Image
三浦 康俊, 李 雪霏, 姜 錫, 坂本 雄児, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 220, 55, 60, 15 Sep. 2016
電子情報通信学会, Japanese

Improvement of ROI Data Hiding Technique for Selected Region of JPEG Image
三浦 康俊, 李 雪霏, 姜 錫, 坂本 雄児, 映像情報メディア学会技術報告 = ITE technical report, 40, 31, 55, 60, Sep. 2016
映像情報メディア学会, Japanese

Additional Data Hiding Technique for Specified Regions of JPEG Image
三浦 康俊, 李 雪霏, 姜 錫, 坂本 雄児, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 33, 1, 6, 19 May 2016
電子情報通信学会, Japanese

Subjective Image and Video Degradation Evaluation Using Privacy Protection Technique
山本 恭徳, 姜 錫, 坂本 雄児, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 115, 397, 75, 80, 18 Jan. 2016
電子情報通信学会, Japanese

コンピュータホログラフィ技術を中心とした超大規模データ処理指向コミュニケーション
松島恭治, 棟安実治, 梶川嘉延, 中原住雄, 四方博之, 徳丸正孝, 田原樹, POPOVSKI Petar, GAN Woon-Seng, 田口亮, 山口雅浩, 坂本雄児, 伊藤智義, 下馬場朋禄, 技苑, 142, 2016

Fast Calculation Method of Computer-generated Hologram Using Geometric Sequence
Sakamoto Yuji, Sugawara Takuya, Watanabe Ryosuke, ITE Technical Report, 39, 34, 17, 20, Sep. 2015
A point light source method and a polygon model are popular methods for modeling and calculation methods of computer-generation hologram. This paper discusses fast calculation methods for a polygon modeling using the calculation method of the point light source method. The methods are based on geometric sequences and provide constant calculation times that are proportional to the number of polygons, but the one of point light sources. Moreover, it is possible to perform very fast calculations using a GPU because the methods are suitable to super parallel calculations., The Institute of Image Information and Television Engineers, Japanese

A Reversible Partial Scrambling Technique Embedding Different Types of Contents
LI Xuefei, KANG Seok, SAKAMOTO Yuji, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 114, 511, 143, 148, 12 Mar. 2015
In this paper, we propose a reversible partial scrambling technique embedding different types of contents. In the proposed technique, for videos with sound, partial scrambling is generated at the same time when the audio data is being embedded into quantized discrete cosine transform (DCT) coefficients of the video data during the coding process to MPEG4 format. For videos with sound muxing standard videos and standard sounds, verification experiments with the MSB values between the original videos and the recovered videos are carried out to verify the effectiveness of the proposed technique., The Institute of Electronics, Information and Communication Engineers, Japanese

Reversible Privacy Protection Technique Controlling Quantitative Scramble Degree and File Size Increase
SHIMAURA Shingo, KANG Seok, SAKAMOTO Yuji, IEICE technical report. Image engineering, 114, 221, 41, 46, 18 Sep. 2014
We propose a reversible privacy protection technique for surveillance camera which enables controlling quantitative scramble degree and file size increase. Our proposed technique combines scrambling method based on square value calculated from target image quality and embedding method using histogram manipulation for reconstruction information in the image compression process, and these are performed in every DCT 8×8 block divided into scrambling area and data hiding area respectively. We confirmed the validity of our technique by scramble degree control experiment with two types of images having different number of people., The Institute of Electronics, Information and Communication Engineers, Japanese

Reversible Privacy Protection Technique Controlling Quantitative Scramble Degree and File Size Increase
島浦 紳吾, 姜 錫, 坂本 雄児, 映像情報メディア学会技術報告 = ITE technical report, 38, 36, 41, 46, Sep. 2014
映像情報メディア学会, Japanese

Histogram Domain Reversible Data Hiding Technique for JPEG Images
SHIMAURA Shingo, HARADA Shohei, KANG Seok, SAKAMOTO Yuji, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 113, 415, 39, 44, 27 Jan. 2014
Xuan proposed a reversible data hiding technique for JPEG images, which embeds secret information using histogram manipulation of the DOT coefficients. The problem regarding Xuan's method revolves around the requirement of the empirical considerations of the two parameters which governs the payload, PSNR, and the file size growth rate of the embedded images. Our method proposes an improvement over Xuan's method, where it can reduce the user's burden and show efficiency of the previous parameters because the conventional parameter have been changed from two to one parameter., The Institute of Electronics, Information and Communication Engineers, Japanese

Evaluation of Threshold Levels using Complexity Distributions in BPCS Steganography Technique
HARADA Syouhei, SHIMAURA Shingo, KANG Seok, SAKAMOTO Yuji, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 113, 415, 33, 38, 27 Jan. 2014
It is necessary to reduce two variance values of the degradation level of stego images and the embedding rate in steganography techniques. We proposed a technique in revaluating threshold levels for judging complexity boundary. This technique can be achieved by determining the complexity distributions, which is consisted by the complexity gained by the judgment of complexity, and the number of macroblocks having the complexity in the BPCS steganography technique, and confirmed the effectiveness. However, parameters used in reevaluation of threshold levels aren't in correlation with the complexity distributions and are set arbitrarily. In this paper, we proposed technique parameters set automatically by a standard deviation of a normal distribution and confirmed the effectiveness by the experiments., The Institute of Electronics, Information and Communication Engineers, Japanese

Comparison between subjective and objective evaluations using VSNR for 3-D image
SUZUKI Kazuhiro, SAKAMOTO Yuji, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 113, 350, 21, 26, 13 Dec. 2013
Some three-dimensional display technology has been noted. Various techniques are proposed and utilized for three-dimensional display technology. We have proposed an objective evaluation method using VSNR in order to compare various techniques. VSNR is a three-dimensionally extended signal to noise ratio (SNR), which represents the difference between the spatial light distributions of reconstructed images and a real object. The subjective evaluation and evaluation by VSNR have not been compared. In this paper, we evaluated three-dimensional images by subjective evaluation and objective evaluation using VSNR., The Institute of Electronics, Information and Communication Engineers, Japanese

一枚の画像からの時空間周波数を用いた揺らめき動画生成法
山本薫, 坂本雄児, 研究報告コンピュータビジョンとイメージメディア（CVIM）, 2013, 3, 1, 6, 21 Nov. 2013
一枚の画像に揺らめくような動きを与えて動画を自動生成する手法がある．本研究では，画像の空間周波数領域に時間周波数軸を加えた三次元の時空間周波数領域上に成分を配置し，三次元フーリエ逆変換を用いて自然界に見られるような複雑さをもつ揺らめきを生成する手法を提案した．また動画生成実験を行い，提案手法によってより自然な揺らめきを生成可能であることを確認した．, 一般社団法人情報処理学会, Japanese

An Evaluation on Controlling File Size Increase in the Image Partial Scrambling Technique Enables Quantitative Degradation Degree Control by Exchanging DCT Coefficients
SHIMAURA Shingo, HARADA Syouhei, KANG Seok, SAKAMOTO Yuji, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 113, 138, 167, 172, 18 Jul. 2013
The partial scrambling which is performed before variable length coding enables quantitative degradation degree control based on PSNR by fluctuation or exchange of DCT coefficients. However, those methods have problems with file size increase and accuracy deterioration of degradation degree control. Therefore, we proposed the image partial scrambling technique which enables controlling file size increase and improving accuracy of degradation degree control. The proposed method exchanges DCT coefficients based on square error value which one DCT coefficient should reach. Then, we compared our method with other methods about accuracy of degradation degree control and file size growth rate., The Institute of Electronics, Information and Communication Engineers, Japanese

An Evaluation on Controlling File Size Increase in the Image Partial Scrambling Technique Enabled Quantitative Degradation Degree Control by Exchanging DCT Coefficients
島浦 紳吾, 原田 翔平, 姜 錫, 坂本 雄児, 研究報告セキュリティ心理学とトラスト（SPT）, 2013, 24, 1, 6, 11 Jul. 2013
Japanese

Evaluation on Judging Methods of Complexity Boundary in BPCS Steganography Technique
HARADA Syouhei, SHIMAURA Shingo, KANG Seok, SAKAMOTO Yuji, 電子情報通信学会技術研究報告 : 信学技報, 112, 420, 83, 88, 29 Jan. 2013
It is necessary to reduce two variance values of a degradation level of stego images and an embedding rate in steganography techniques We proposed a technique reevaluating threshold levels for judging complexity boundary by the complexity distributions consisting of complexity gained by judgment of complexity and the number of macroblocks having the complexity in BPCS steganography technique There are vanous complexity judging methods based on side lengths of the boundary line, DF-expressions, 4-neighbor, 8-neighbor, etc In this paper, we discussed the most suitable judging method using the variance values and the computation time calculated by vanous complexity judging methods on the complexity judgment in proposed technique., The Institute of Electronics, Information and Communication Engineers, Japanese

Generation Method of Animation from Pictures with Natural Flicker
山本薫, 坂本雄児, IPSJ SIG Notes, 2012, 7, 1, 6, 26 Nov. 2012
Some methods to create animation automatically from one picture have been proposed. There is a method that gives a flicker to a picture to make animation. However, the flicker generated by the simple harmonic motion causes monotonous animation. In this study, we propose the method of creating complex and natural flicker by using 1/fβ noise seen often in nature. We carried out the experiment that compares the proposed method to the conventional method by the subjective appraisal, and confirmed the adequacy of the proposed method., Information Processing Society of Japan (IPSJ), Japanese

二枚の写真からの揺らめき動画生成のための対象領域およびパラメータの自動推定法
山本薫, 坂本雄児, インテリジェント・システム・シンポジウム(CD-ROM), 22nd, ROMBUNNO.1B2-1, 30 Aug. 2012
Japanese

VSNRを用いた3次元表示された画像の客観的画質評価手法
鈴木一弘, 坂本雄児, インテリジェント・システム・シンポジウム(CD-ROM), 22nd, ROMBUNNO.1B2-2, 30 Aug. 2012
Japanese

Reevaluation of Threshold Levels for Judging Complexity Boundary Using Distributions of Complexity in BPCS Steganography Technique
原田 翔平, 姜 錫, 坂本 雄児, 電子情報通信学会技術研究報告 : 信学技報, 112, 126, 1, 8, 19 Jul. 2012
電子情報通信学会, Japanese

Reevaluation of Threshold Levels for Judging Complexity Boundary Using Distributions of Complexity in BPCS Steganography Technique
原田 翔平, 姜 錫, 坂本 雄児, 電子情報通信学会技術研究報告 : 信学技報, 112, 127, 1, 8, 19 Jul. 2012
電子情報通信学会, Japanese

Reevaluation of Threshold Levels for Judging Complexity Boundary Using Distributions of Complexity in BPCS Steganography Technique
原田 翔平, 姜 錫, 坂本 雄児, 電子情報通信学会技術研究報告 : 信学技報, 112, 128, 1, 8, 19 Jul. 2012
電子情報通信学会, Japanese

Reevaluation of Threshold Levels for Judging Complexity Boundary Using Distributions of Complexity in BPCS Steganography Technique
原田 翔平, 姜 錫, 坂本 雄児, 電子情報通信学会技術研究報告 : 信学技報, 112, 129, 1, 8, 19 Jul. 2012
電子情報通信学会, Japanese

Reevaluation of Threshold Levels for Judging Complexity Boundary Using Distributions of Complexity in BPCS Steganography Technique
HARADA SHOHEI, KANG SEOK, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 112, 129(EMM2012 1-34), 1-8, 8, 12 Jul. 2012
In this paper, we propose a technique reducing two dispersion values of a degradation level of stego images and a embedding rate in BPCS steganography technique. Threshold levels for judging complexity boundary are reevaluated by distributions of complexity which consist of complexity gained by judgment of complexity and a number of macro-blocks having its complexity. Secret information is reconstructed by the exclusive OR calculation with pseudo-random number bit by bit to avoid line noise in stego images, and then these reconstructed information is embedded into a dummy image. Experimental results about two dispersion values of a degradation level of stego images and a embedding rate have shown the validity of proposed technique., The Institute of Electronics, Information and Communication Engineers, Japanese

Object Extraction Method for Image-based Modeling using Projection Transformation of Multi-viewpoint Images
IBARAKI MASANORI, SAKAMOTO YUJI, 情報処理学会研究報告(CD−ROM), 2011, 4, ROMBUNNO.CG-145,NO.28, 15 Dec. 2011
Japanese

Object Extraction Method for Image-based Modeling using Projection Transformation of Multi-viewpoint Images
Masanori Ibaraki, Yuji Sakamoto, IPSJ SIG Notes. CVIM, 2011, 28, 1, 6, 10 Nov. 2011
The volume intersection method is effective as modeling 3D objects from the multi-viewpoint images. It is important for generating 3D models from the images to extract object area in the images. This paper presents an object extraction method by using projection transformation of multi-viewpoint images. In conventional background subtraction and segmentation methods, there have a limitation caused by the shadow and complex texture in the images. The proposed method is a robust for the shadow and textures problems, so it applied to construct 3D models in various scenes. The experiments ware ..., Information Processing Society of Japan (IPSJ), Japanese

フーリエ変換光学系における自由な奥行きで再生可能な計算機合成ホログラム
佐藤裕典, 坂本雄児, 情報科学技術フォーラム, FIT 2011, 287-288, 22 Aug. 2011
Japanese

半開示スクランブル動画に適用可能な電子透かし技法
若色宏明, KANG Seok, 坂本雄児, 情報科学技術フォーラム, FIT 2011, 509-510, 22 Aug. 2011
Japanese

基準平面への平行投影を用いた多視点画像からの物体領域抽出
茨木雅典, 坂本雄児, 情報科学技術フォーラム, FIT 2011, 389-390, 22 Aug. 2011
Japanese

球形基本物体光を用いた計算機合成ホログラムの計算における拡大・縮小とスキュー変換の実装
細谷地航平, 坂本雄児, 情報科学技術フォーラム, FIT 2011, 283-284, 22 Aug. 2011
Japanese

TIPのための穴の開いた物体の三次元モデル生成手法
福田康範, 坂本雄児, 情報科学技術フォーラム, FIT 2011, 381-382, 22 Aug. 2011
Japanese

接眼型電子ホログラフィにおける視野の拡大と物体の奥行きの調節
ヤン チャンヨン, 坂本雄児, 情報科学技術フォーラム, FIT 2011, 289-290, 22 Aug. 2011
Japanese

計算機合成ホログラムにおけるポリゴンモデルを用いた反射特性付与法
山口一弘, 市川翼, 坂本雄児, 情報科学技術フォーラム, FIT 2011, 281-282, 22 Aug. 2011
Japanese

計算機合成ホログラムを用いた立体映像の評価法
坂本雄児, 情報科学技術フォーラム, FIT 2011, 291-292, 22 Aug. 2011
Japanese

ホログラム面からの逆追跡によるCGH計算法
市川翼, 坂本雄児, 情報科学技術フォーラム, FIT 2011, 285-286, 22 Aug. 2011
Japanese

DCT係数の交換によるスクランブル画像のファイルサイズの増加を抑制した半開示スクランブル技法
CHOU Kizawa, KANG Seok, 坂本雄児, 情報科学技術フォーラム, FIT 2011, 511-512, 22 Aug. 2011
Japanese

The Present and the Future of 3D Holo TVs
SAKAMOTO Yuji, The Journal of the Institute of Image Electronics Engineers of Japan, 40, 3, 489, 493, 25 May 2011
The Institute of Image Electronics Engineers of Japan, Japanese

Calculation method for computer-generated hologram considering refraction by transparent objects
笹森 新, 山口 一弘, 坂本 雄児, IEICE technical report, 110, 421, 175, 180, 21 Feb. 2011
電子情報通信学会, Japanese

Calculation Method for Computer-Generated Hologram Considering Refraction by Transparent Objects
SASAMORI Arata, YAMAGUCHI Kazuhiro, SAKAMOTO Yuji, ITE technical report, 35, 9, 175, 180, 14 Feb. 2011
A computer-generated hologram (CGH) is a technology expected to achieve ideal 3D displays. To display realistic 3D images using a CGH, it is necessary to develop rendering technologies. However, studies about them are not sufficient. Especially, a method for expressing refraction that arises when a light passes through a transparent object is not established. We describe a new calculation method for CGH considering refraction. This method is based on a ray-tracing method used in computer graphics. We made holograms by this method and reconstructed optical images with refraction by transparent objects like lenses. We confirmed the validity of the proposed method., The Institute of Image Information and Television Engineers, Japanese

Elimination of Conjugate Image and Enlargement of Object Reconstruction Area in Computer-Generated Hologram using Fourier Transform Optical System
SATO Yusuke, SAKAMOTO Yuji, ITE technical report, 35, 9, 29, 34, 14 Feb. 2011
Computer-generated hologram (CGH) is a hologram generated by simulating recording process in optical holography. CGH is expected to apply to future 3D Displays. To display 3D images that have realistic sensation, a method using Fourier transform optical system have already been proposed. This method enlarge visual field and viewing zone. However, in this conventional method, object reconstruction area is restricted. Therefore, images are not able to reconstruct near a hologram. This paper proposes a method for enlarging object reconstruction area, and a conjugate image elimination method. Optical reconstruction experiments were carried out, and the results show that the proposed methods are effective., The Institute of Image Information and Television Engineers, Japanese

A Method of Generating Three Dimensional Models of Various Objects using Silhouette Images for TIP
FUKUTA Yasunori, SAKAMOTO Yuji, ITE technical report, 35, 9, 23, 28, 14 Feb. 2011
"Tour Into the Picture (TIP)" is one of Image-based rendering method for walk-through from a single image. A problem of TIP is to be incapable with large movement of viewpoint because foreground objects are flat plates. To solve the problem, there is a method to generate three dimensional models of foreground objects, but the method is to be incapable with intricately-shaped objects. The proposed method generates three dimensional models of various shapes from silhouette images of the objects by using proper method according to the shape of object. Experiments were carried out, and the result shows that the proposed method generates three dimensional models which conventional method cannot generate., The Institute of Image Information and Television Engineers, Japanese

Effects of Parameters on Images for Computer-Generated Holograms using Multi-View Images
HONDA Yasuhiro, SAKAMOTO Yuji, ITE technical report, 35, 9, 17, 22, 14 Feb. 2011
Holography is an ideal 3-D display technology which reconstruct the object light. Computer-Generated Holograms (CGH) made with simple equipment. We had proposed the method for CGH from the multi-view images taken with normal cameras, and reduction of image number by generating in between images using Shape-From-Silhouette. However, images quality decreases when the object is complex. This paper reserchs about effects of camera parameters on generated images., The Institute of Image Information and Television Engineers, Japanese

A Method of Generating Three Dimensional Models of Various Objects using Silhouette Images for TIP
FUKUTA YASUNORI, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 110, 421(IE2010 104-144), 23-28, 28, 14 Feb. 2011
"Tour Into the Picture (TIP)" is one of Image-based rendering method for walk-through from a single image. A problem of TIP is to be incapable with large movement of viewpoint because foreground objects are flat plates. To solve the problem, there is a method to generate three dimensional models of foreground objects, but the method is to be incapable with intricately-shaped objects. The proposed method generates three dimensional models of various shapes from silhouette images of the objects by using proper method according to the shape of object. Experiments were carried out, and the result shows that the proposed method generates three dimensional models which conventional method cannot generate., The Institute of Image Information and Television Engineers, Japanese

Calculation Method for Computer-Generated Hologram Considering Refraction by Transparent Objects
SASAMORI ARATA, YAMAGUCHI KAZUHIRO, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 110, 421(IE2010 104-144), 175-180, 180, 14 Feb. 2011
電子情報通信学会, Japanese

Effects of Parameters on Images for Computer-Generated Holograms using Multi-View Images
HONDA YASUHIRO, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 110, 421(IE2010 104-144), 17-22, 22, 14 Feb. 2011
Holography is an ideal 3-D display technology which reconstruct the object light. Computer-Generated Holograms (CGH) made with simple equipment. We had proposed the method for CGH from the multi-view images taken with normal cameras, and reduction of image number by generating in between images using Shape-From-Silhouette. However, images quality decreases when the object is complex. This paper reserchs about effects of camera parameters on generated images., The Institute of Image Information and Television Engineers, Japanese

Elimination of Conjugate Image and Enlargement of Object Reconstruction Area in Computer-Generated Hologram using Fourier Transform Optical System
SATO YUSUKE, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 110, 421(IE2010 104-144), 29-34, 34, 14 Feb. 2011
Computer-generated hologram (CGH) is a hologram generated by simulating recording process in optical holography. CGH is expected to apply to future 3D Displays. To display 3D images that have realistic sensation, a method using Fourier transform optical system have already been proposed. This method enlarge visual field and viewing zone. However, in this conventional method, object reconstruction area is restricted. Therefore, images are not able to reconstruct near a hologram. This paper proposes a method for enlarging object reconstruction area, and a conjugate image elimination method. Optical reconstruction experiments were carried out, and the results show that the proposed methods are effective., The Institute of Image Information and Television Engineers, Japanese

微小面を用いた計算機合成ホログラムにおける反射特性付与法のGPUによる高速化
山口一弘, 市川翼, 坂本雄児, Optics & Photonics Japan講演予稿集(CD−ROM), 2011, ROMBUNNO.30PD4, 2011
Japanese

Model Generation for Climbing Plants Using Growth Simulation
SHINDO ARI, SAKAMOTO YUJI, 情報処理学会研究報告(CD−ROM), 2010, 4, ROMBUNNO.CG-141,11, 15 Dec. 2010
Japanese

Model Generation for Climbing Plants Using Growth Simulation
Ari Shindo, Yuji Sakamoto, IPSJ SIG Notes, 2010, 11, 1, 6, 01 Nov. 2010
Climbing plants attract attention because they are suited for making green spaces along the wall of buildings. Particularly, model generation methods for climbing plants are useful for prediction and estimation of scenery after greening. Then, this paper presents a model generation method using growth simulation with L-system. First, the proposed method sets rules of L-system. Second, the proposed method simulates the growth using the rules, and controls growth and blanching. The positions of buds in three dimensional space are searched considering the behavior of sucker and light requireme..., Information Processing Society of Japan (IPSJ), Japanese

Enlargement of object reconstruction area in computer-generated hologram using the Fourier transform optical system
SATO Yusuke, SAKAMOTO Yuji, ITE Technical Report, 251, 0, 1, 4, 23 Jul. 2010
Computer-generated hologram (CGH) is a hologram generated by simulating recording process in optical holography. High resolution output devices are required to observe 3D images. However, resolution of output devices is not high enough to display interference pattern. Therefore, viewing zone and visual field are limited. To improve these problems, this paper proposes a method for enlargement visual field by enlarging reconstruction area in CGH using the Fourier transform optical system. Optical reconstruction experiments were carried out, and results of these experiments showed that the proposed method enlarge visual field and reconstruction area., The Institute of Image Information and Television Engineers, Japanese

A method of generating of solid models from a single landscape image for TIP
FUKUTA Yasunori, SAKAMOTO Yuji, ITE Technical Report, 251, 0, 9, 12, 23 Jul. 2010
"Tour Into the Picture (TIP)" is one of Image-based rendering method for actualizing walk-through from a single image. This paper proposes a method of constructing three dimensional space from a single landscape image using TIP. A problem of TIP is to be incapable with large movement of viewpoint because foreground objects are flat plates. To solve the problem of TIP, the proposed method generates solid models of foreground objects, and constructs three dimensional space with the models and a background image. An experiment was carried out, and the result shows that reasonable three dimensional space is constructed from a landscape image., The Institute of Image Information and Television Engineers, Japanese

The present and the future of 3D Holo TVs
SAKAMOTO Yuji, ITE Technical Report, 251, 0, 21, 24, 23 Jul. 2010
Recently, 3D films and 3D TV sets are releasing and we can watch 3D images in daily life. However, the stereoscopic method used by these 3D systems are not suited for human perceptual for three dimensional objects. A Holo TV system based on a holographic technique is an ideal 3D communicate system, unfortunately, it has never been realized for a commercial base because it has technical difficulties. In many laboratories around the world, researchers study Holo TV systems, and these researches have been greatly advanced during this decade. This paper introduces the present of researches and the difficulties for the realization, at the last discuss problems needed to solve and the future of the 3D Holo TV., The Institute of Image Information and Television Engineers, Japanese

Enlargement of Object Reconstruction Area in Computer-Generated Hologram using the Fourier Transform Optical System
SATO Yusuke, SAKAMOTO Yuji, ITE Technical Report, 34, 31, 1, 4, 23 Jul. 2010
Computer-generated hologram (CGH) is a hologram generated by simulating recording process in optical holography. High resolution output devices are required to observe 3D images. However, resolution of output devices is not high enough to display interference pattern. Therefore, viewing zone and visual field are limited. To improve these problems, this paper proposes a method for enlargement visual field by enlarging reconstruction area in CGH using the Fourier transform optical system. Optical reconstruction experiments were carried out, and results of these experiments showed that the pro..., The Institute of Image Information and Television Engineers, Japanese

Calculation Method of Computer-Generated Hologram Using Ray Tracing Method Considering Refraction
SASAMORI Arata, YAMAGUCHI Kazuhiro, SAKAMOTO Yuji, ITE Technical Report, 34, 31, 5, 8, 23 Jul. 2010
A computer-generated hologram (CGH) is a technology expected to achieve ideal 3D displays. To achieve realistic 3D displays using a CGH, it is necessary to establish rendering technologies. However, studies about them are not sufficient. Especially, an established method for expressing refraction that arises when a light passes through a transparent object is not available. We describe a new calculation method considering refraction. This method is based on a ray-tracing method used to express optical phenomena such as refraction in computer graphics. We made holograms by this method and co..., The Institute of Image Information and Television Engineers, Japanese

A Method of Generating of Solid Models from a Single Landscape Image for TIP
FUKUTA Yasunori, SAKAMOTO Yuji, ITE Technical Report, 34, 31, 9, 12, 23 Jul. 2010
"Tour Into the Picture (TIP)" is one of Image-based rendering method for actualizing walk-through from a single image. This paper proposes a method of constructing three dimensional space from a single landscape image using TIP. A problem of TIP is to be incapable with large movement of viewpoint because foreground objects are flat plates. To solve the problem of TIP, the proposed method generates solid models of foreground objects, and constructs three dimensional space with the models and a background image. An experiment was carried out, and the result shows that reasonable three dimensi..., The Institute of Image Information and Television Engineers, Japanese

The Present and the Future of 3D Holo TVs
SAKAMOTO Yuji, ITE Technical Report, 34, 31, 21, 24, 23 Jul. 2010
Recently, 3D films and 3D TV sets are releasing and we can watch 3D images in daily life. However, the stereoscopic method used by these 3D systems are not suited for human perceptual for three dimensional objects. A Holo TV system based on a holographic technique is an ideal 3D communicate system, unfortunately, it has never been realized for a commercial base because it has technical difficulties. In many laboratories around the world, researchers study Holo TV systems, and these researches have been greatly advanced during this decade. This paper introduces the present of researches and ..., The Institute of Image Information and Television Engineers, Japanese

An Evaluation of Controlling Increase of Data Size in the Partial Scrambling Technique Considering Visual Characteristics
JIN Tomohiro, KANG Seok, SAKAMOTO Yuji, ITE Technical Report, 34, 31, 57, 60, 23 Jul. 2010
This paper proposes a decreasing technique of increase rate of data size in the partial scrambling technique. In the proposed technique, quantized DCT coefficients in I-frames are shuffled or changed by a target image quality for PSNR. The amount of change to scramble is corrected in order to be independent on the kinds of videos, and to shuffle or to change the quantized DCT coefficients is selected to decrease the increase rate of data size. In addition, the result of increase rate of data size and subjective evaluation experiment show the effectiveness of the proposed technique., The Institute of Image Information and Television Engineers, Japanese

Calculation method of computer-generated hologram using ray tracing method considering refraction
SASAMORI Arata, YAMAGUCHI Kazuhiro, SAKAMOTO Yuji, ITE Technical Report, 251, 0, 5, 8, 23 Jul. 2010
A computer-generated hologram (CGH) is a technology expected to achieve ideal 3D displays. To achieve realistic 3D displays using a CGH, it is necessary to establish rendering technologies. However, studies about them are not sufficient. Especially, an established method for expressing refraction that arises when a light passes through a transparent object is not available. We describe a new calculation method considering refraction. This method is based on a ray-tracing method used to express optical phenomena such as refraction in computer graphics. We made holograms by this method and conducted optical reconstruction experiments. The results of these experiments showed that the proposed method is valid to display objects with refraction., The Institute of Image Information and Television Engineers, Japanese

An evaluation of controlling increase of data size in the partial scrambling technique considering visual characteristics
JIN Tomohiro, KANG Seok, SAKAMOTO Yuji, ITE Technical Report, 251, 0, 57, 60, 23 Jul. 2010
This paper proposes a decreasing technique of increase rate of data size in the partial scrambling technique. In the proposed technique, quantized DCT coefficients in I-frames are shuffled or changed by a target image quality for PSNR. The amount of change to scramble is corrected in order to be independent on the kinds of videos, and to shuffle or to change the quantized DCT coefficients is selected to decrease the increase rate of data size. In addition, the result of increase rate of data size and subjective evaluation experiment show the effectiveness of the proposed technique., The Institute of Image Information and Television Engineers, Japanese

計算機合成ホログラムにおける反射特性付与法--Blinn・Torrance-Sparrow反射モデルを用いた反射特性
山口 一弘, 坂本 雄児, 画像ラボ, 21, 7, 1, 4, Jul. 2010
日本工業出版, Japanese

Model Generation Method for Climbing Plants Considering Behavior of Sucker for Computer Graphics
SHINDO ARI, SAKAMOTO YUJI, 映像情報メディア学会技術報告, 34, 6(AIT2010 1-48/HI2010 1-48/ME2010 1-48), 233, 238, 15 Feb. 2010
Urban greening has been campaigned actively today. Climbing plants attract attention because they are suited for making green spaces along the wall of buildings. Particularly, model generation methods for climbing plants are useful for prediction and estimation of scenery after greening. This paper presents a model generation method considering behavior of sucker using growth simulation with L-system. First, the proposed method defines symbols meaning the structure of climbing plants, and sets rules of L-system considering behavior that is observed from real climbing plants. Second, the proposed method simulates the growth with rules to control branching along the condition of buds. Using the method of directed random walk, one of slate points is selected as the position of bud in three dimensional space. At the end of this paper, we compare between the results using this method and the growth of real climbing plants, and consider the results., The Institute of Image Information and Television Engineers, Japanese

Study on Reduction of Image Number for Computer-Generated Holograms using Multi-View Images
HONDA YASUHIRO, SAKAMOTO YUJI, 映像情報メディア学会技術報告, 34, 6(AIT2010 1-48/HI2010 1-48/ME2010 1-48), 227, 232, 15 Feb. 2010
Holography is an ideal 3-D display technology which can reconstruct the object light. Computer-Generated Holograms (CGH) made with simple equipment. We had proposed the method for CGH from the multi-view images taken with a common camera. However, the number of multi-view images are enormous. This paper proposes the reduction method of the number of images for CGH by using Shape-From-Silhouette. As a result, the holograms of almost the same quality were generated from very few images compared with the conventional method., The Institute of Image Information and Television Engineers, Japanese

Extraction of Retinal Pigment Epithelium Layers from Optical Coherence Tomography using Active Contour Model with Structuring Elements
MIKAMI HIROSATO, SAKAMOTO YUJI, 映像情報メディア学会技術報告, 34, 6(AIT2010 1-48/HI2010 1-48/ME2010 1-48), 215, 220, 15 Feb. 2010
We suggested a method which was contour extraction using active contour model with structuring elements and studied about extract layers of vertebrate retina from Optical Coherence Tomography (OCT). In this paper, We obtain extraction Retina Pigment Epithelium (RPE) layer using result which extract two layers of vertebrate retina and edge data which obtain differential filter. we evaluate to obtain extraction accuracy., The Institute of Image Information and Television Engineers, Japanese

Extraction of Retinal Pigment Epithelium Layers from Optical Coherence Tomography using Active Contour Model with Structuring Elements
MIKAMI Hirosato, SAKAMOTO Yuji, ITE Technical Report, 34, 6, 215, 220, 15 Feb. 2010
We suggested a method which was contour extraction using active contour model with structuring elements and studied about extract layers of vertebrate retina from Optical Coherence Tomography (OCT). In this paper, We obtain extraction Retina Pigment Epithelium (RPE) layer using result which extract two layers of vertebrate retina and edge data which obtain differential filter. we evaluate to obtain extraction accuracy., The Institute of Image Information and Television Engineers, Japanese

Study on Reduction of Image Number for Computer-Generated Holograms using Multi-View Images
HONDA Yasuhiro, SAKAMOTO Yuji, ITE Technical Report, 34, 6, 227, 232, 15 Feb. 2010
Holography is an ideal 3-D display technology which can reconstruct the object light. Computer-Generated Holograms (CGH) made with simple equipment. We had proposed the method for CGH from the multi-view images taken with a common camera. However, the number of multi-view images are enormous. This paper proposes the reduction method of the number of images for CGH by using Shape-From-Silhouette. As a result, the holograms of almost the same quality were generated from very few images compared with the conventional method., The Institute of Image Information and Television Engineers, Japanese

Model Generation Method for Climbing Plants Considering Behavior of Sucker for Computer Graphics
SHINDO Ari, SAKAMOTO Yuji, ITE Technical Report, 34, 6, 233, 238, 15 Feb. 2010
Urban greening has been campaigned actively today. Climbing plants attract attention because they are suited for making green spaces along the wall of buildings. Particularly, model generation methods for climbing plants are useful for prediction and estimation of scenery after greening. This paper presents a model generation method considering behavior of sucker using growth simulation with L-system. First, the proposed method defines symbols meaning the structure of climbing plants, and sets rules of L-system considering behavior that is observed from real climbing plants. Second, the pro..., The Institute of Image Information and Television Engineers, Japanese

Extraction of Retinal Pigment Epithelium Layers from Optical Coherence Tomography using Active Contour Model with Structuring Elements
MIKAMI Hirosato, SAKAMOTO Yuji, IEICE technical report, 109, 414, 215, 220, 08 Feb. 2010
We suggested a method which was contour extraction using active contour model with structuring elements and studied about extract layers of vertebrate retina from Optical Coherence Tomography(OCT). In this paper, We obtain extraction Retina Pigment Epithelium(RPE)layer using result which extract two layers of vertebrate retina and edge data which obtain differential filter. We evaluate to obtain extraction accuracy., The Institute of Electronics, Information and Communication Engineers, Japanese

Study on Reduction of Image Number for Computer-Generated Holograms using Multi-View Images
HONDA Yasuhiro, SAKAMOTO Yuji, IEICE technical report, 109, 414, 227, 232, 08 Feb. 2010
Holography is an ideal 3-D display technology which can reconstruct the object light. Computer-Generated Holograms(CGH) made with simple equipment. We had proposed the method for CGH from the multi-view images taken with a common camera. However, the number of multi-view images are enormous. This paper proposes the reduction method of the number of images for CGH by using Shape-From-Silhouette. As a result, the holograms of almost the same quality were generated from very few images compared with the conventional method., The Institute of Electronics, Information and Communication Engineers, Japanese

Model Generation Method for Climbing Plants Considering Behavior of Sucker for Computer Graphics
SHINDO Ari, SAKAMOTO Yuji, IEICE technical report, 109, 414, 233, 238, 08 Feb. 2010
Urban greening has been campaigned actively today. Climbing plants attract attention because they are suited for making green spaces along the wall of buildings. Particularly, model generation methods for climbing plants are useful for prediction and estimation of scenery after greening. This paper presents a model generation method considering behavior of sucker using growth simulation with L-system. First, the proposed method defines symbols meaning the structure of climbing plants, and sets rules of L-system considering behavior that is observed from real climbing plants. Second, the pro..., The Institute of Electronics, Information and Communication Engineers, Japanese

Extraction of Retinal Pigment Epithelium Layers from Optical Coherence Tomography using Active Contour Model with Structuring Elements
MIKAMI Hirosato, SAKAMOTO Yuji, IEICE technical report. Image engineering, 109, 415, 215, 220, 08 Feb. 2010
We suggested a method which was contour extraction using active contour model with structuring elements and studied about extract layers of vertebrate retina from Optical Coherence Tomography(OCT). In this paper, We obtain extraction Retina Pigment Epithelium(RPE) layer using result which extract two layers of vertebrate retina and edge data which obtain differential filter. we evaluate to obtain extraction accuracy., The Institute of Electronics, Information and Communication Engineers, Japanese

Study on Reduction of Image Number for Computer-Generated Holograms using Multi-View Images
HONDA Yasuhiro, SAKAMOTO Yuji, IEICE technical report. Image engineering, 109, 415, 227, 232, 08 Feb. 2010
Holography is an ideal 3-D display technology which can reconstruct the object light. Computer-Generated Holograms(CGH) made with simple equipment. We had proposed the method for CGH from the multi-view images taken with a common camera. However, the number of multi-view images are enormous. This paper proposes the reduction method of the number of images for CGH by using Shape-From-Silhouette. As a result, the holograms of almost the same quality were generated from very few images compared with the conventional method., The Institute of Electronics, Information and Communication Engineers, Japanese

Model Generation Method for Climbing Plants Considering Behavior of Sucker for Computer Graphics
SHINDO Ari, SAKAMOTO Yuji, IEICE technical report. Image engineering, 109, 415, 233, 238, 08 Feb. 2010
Urban greening has been campaigned actively today. Climbing plants attract attention because they are suited for making green spaces along the wall of buildings. Particularly, model generation methods for climbing plants are useful for prediction and estimation of scenery after greening. This paper presents a model generation method considering behavior of sucker using growth simulation with L-system. First, the proposed method defines symbols meaning the structure of climbing plants, and sets rules of L-system considering behavior that is observed from real climbing plants. Second, the pro..., The Institute of Electronics, Information and Communication Engineers, Japanese

A Partial Video Scrambling Technique by Changing Motion Vectors and Its Evaluation
MIYAKAWA KENTARO, KANG SEOK, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 109, 379(LOIS2009 60-78), 37, 42, 14 Jan. 2010
Partial video scrambling techniques which don't encrypt but degrade video contents have been proposed in order to use the scrambled video as the sample video in paid video delivery services. Deliverers can make scrambled videos which have degrading degree needed by controlling the scrambling strength. In this study, we proposed a partial video scrambling technique by changing the values of motion vectors of MPEG and evaluated the degrading degree and concealing degree of the scrambled videos., The Institute of Electronics, Information and Communication Engineers, Japanese

Reconstructing Three-dimensional Models from Multi-View Images Using BSC Method and Its Evaluation
SUMIYOSHI SHIN'ICHI, SAKAMOTO YUJI, 映像情報メディア学会技術報告, 33, 55(BCT2009 135-150), 17, 22, 07 Dec. 2009
Methods which reconstruct 3D models from multi-view images come to the front due to recent advancement in image processing. There is a matter to be incapable of concavo-convex shape with spike in convention methods reconstructing 3D models from multi-view images. This paper proposes a method reconstructing 3D models from multi-view images of the object with concavo-convex shape and investigates a method to evaluate its models The proposed method calculates a field including proper surface of the object using Block Space Carving method and deforms the model in it. In deformation, the proposed method calculates a base surface of the object and deforms the model as a center of it. The proposed method reconstructs 3D models more accurate than conventional methods, by this processing. After deformation, the proposed method synthesizes 2D images at the camera positions the captured photographs and estimates accuracy of the 3D models. Replicating the deformation and the estimation accuracy of the 3D models, the proposed method reconstructs 3D models considering concavo-convex shape. At the end of this paper, the proposed method runs simulation experiments and experiments with photographed images. In the simulation experiments, the investigated method compares voxel data reconstructed from multi-view images with voxel data made from CG models data of the objects. In the experiments with photographed images, this paper evaluate the 3D models using PSNR. These results show that the proposed method is effective., The Institute of Image Information and Television Engineers, Japanese

Reconstructing Three-dimensional Models from Multi-View Images Using BSC Method and Its Evaluation
SUMIYOSHI Shinichi, SAKAMOTO Yuji, IEICE technical report. Communication systems, 109, 322, 17, 22, 30 Nov. 2009
Methods which reconstruct 3D models from multi-view images come to the front due to recent advancement in image processing. There is a matter to be incapable of concavo-convex shape with spike in conventional methods reconstructing 3D models from multi-view images. This paper proposes a method reconstructing 3D models from multi-view images of the object with concavo-convex shape and investigates a method to evaluate its models. The proposed method calculates a field including proper surface of the object using Block Space Carving method and deforms the model in it. In deformation, the prop..., The Institute of Electronics, Information and Communication Engineers, Japanese

構造要素を用いた動的輪郭モデルによる輪郭抽出法の構造要素形状による影響
三上博理, 坂本雄児, 映像情報メディア学会冬季大会講演予稿集(CD-ROM), 2009, ROMBUNNO.9-10, 27 Nov. 2009
Japanese

Synthesizing Arbitrary Viewpoint Images from Multi-View Images Considering Concavo-convex Shape
SUMIYOSHI SHIN'ICHI, SAKAMOTO YUJI, 映像情報メディア学会技術報告, 33, 44(ME2009 175-186), 31, 34, 26 Oct. 2009
This paper proposes an effective method to synthesize arbitrary viewpoint images for the object with concavo-convex shape by constructing a 3D model from multi-view images. In the proposed method, a field which should be deformed in the 3D model is calculated with Block Space Carving method based on Space Carving method. In addition, the proposed method synthesizes 2D images at the camera positions that captured photographs and acquires robust evaluation objects for the 3D model. The proposed method constructs the 3D model considering concavo-convex shape by deforming the 3D model in the field while comparing 2D images with the photographs. At the end of this paper, the results of the simulation experiments with synthesizing arbitrary viewpoint images show that the proposed method is effective., The Institute of Image Information and Television Engineers, Japanese

DCT係数のDC成分と動きベクトルの変更による動画スクランブル技法の画質制御に関する考察
宮川健太朗, KANG Seok, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2009, ROMBUNNO.167, 17 Oct. 2009
Japanese

生長シミュレーションを用いたツタのCGモデル生成手法
進藤亜梨, 坂本雄児, 情報科学技術フォーラム, FIT 2009, 3, 249, 250, 20 Aug. 2009
Forum on Information Technology, Japanese

I-004 A Model Generation Method for Climbing Plants Using Growth Simulation for Computer Graphics
Shindo Ari, Sakamoto Yuji, 情報科学技術フォーラム講演論文集, 8, 3, 249, 250, 20 Aug. 2009
Forum on Information Technology, Japanese

Extraction of Layers of Vertebrate Retina from Optical Coherence Tomography Images by using Active Contour Model with Structuring Elements
MIKAMI Hirosato, KONISHI Hayato, SAKAMOTO Yuji, IEICE technical report, 2009, 71, 17, 22, 26 Jun. 2009
Optical Coherence Tomography images (OCT) have problems such as speckle noise and shadowing. Therefore, it is difficult for general segmentation algorithms to extract layers of vertebrate retina. To solve this problem, a method which was contour extraction using active contour model with struturing elements in three-dimensional space was proposed. In this paper, we perform experiments to apply the method to OCT and obtain extraction accuracy of more than 99.5%., The Institute of Electronics, Information and Communication Engineers, Japanese

Extraction of Layers of Vertebrate Retina from Optical Coherence Tomography Images by using Active Contour Model with Structuring Elements
MIKAMI HIROSATO, KONISHI HAYATO, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 109, 106(MBE2009 13-17), 17, 22, 19 Jun. 2009
Optical Coherence Tomography images (OCT) have problems such as speckle noise and shadowing. Therefore, it is difficult for general segmentation algorithms to extract layers of vertebrate retina. To solve this problem, a method which was contour extraction using active contour model with struturing elements in three-dimensional space was proposed. In this paper, we perform experiments to apply the method to OCT and obtain extraction accuracy of more than 99.5%., The Institute of Electronics, Information and Communication Engineers, Japanese

Extraction of Layers of Vertebrate Retina from Optical Coherence Tomography Images by using Active Contour Model with Structuring Elements
MIKAMI Hirosato, KONISHI Hayato, SAKAMOTO Yuji, IEICE technical report. ME and bio cybernetics, 109, 106, 17, 22, 19 Jun. 2009
Optical Coherence Tomography images (OCT) have problems such as speckle noise and shadowing. Therefore, it is difficult for general segmentation algorithms to extract layers of vertebrate retina. To solve this problem, a method which was contour extraction using active contour model with struturing elements in three-dimensional space was proposed. In this paper, we perform experiments to apply the method to OCT and obtain extraction accuracy of more than 99.5%., The Institute of Electronics, Information and Communication Engineers, Japanese

The Reflective LCD Electro-Holography Allowing for the Wide Viewing Area and Viewing Field using the Fourier Tranform Optical System
KATO Atsushi, SAKAMOTO Yuji, ITE Technical Report, 33, 6, 207, 212, 04 Feb. 2009
Electro-Holography using a reflective LCD is expected as the 3-dimensional movie display technology in the future. We realized the reflective LCD Electro-Holography allowing for the wide viewing zone and visual field using the Fourier transform optical system. In addition, we estimated the size of reconstructed image, the distance for looking in both eyes, the region that place an object in our optical system theoretically. We performed the optical experiments and confirmed their results with reconstructed images., The Institute of Image Information and Television Engineers, Japanese

The Reflective LCD Electro-Holography Allowing for the Wide Viewing Area and Viewing Field using the Fourier Tranform Optical System
KATO ATSUSHI, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 108, 425(IE2008 204-252), 207, 212, 28 Jan. 2009
Japanese

The Reflective LCD Electro-Holography Allowing for the Wide Viewing Area and Viewing Field using the Fourier Tranform Optical System
KATO Atsushi, SAKAMOTO Yuji, IEICE technical report. Image engineering, 108, 425, 207, 212, 28 Jan. 2009
Electro-Holography using a reflective LCD is expected as the 3-dimensional movie display technology in the future. We realized the reflective LCD Electro-Holography allowing for the wide viewing zone and visual field using the Fourier transform optical system. In addition, we estimated the size of reconstructed image, the distance for looking in both eyes, the region that place an object in our optical system theoretically. We performed the optical experiments and confirmed their results with reconstructed images., The Institute of Electronics, Information and Communication Engineers, Japanese

The Reflective LCD Electro-Holography Allowing for the Wide Viewing Area and Viewing Field using the Fourier Tranform Optical System
KATO Atsushi, SAKAMOTO Yuji, IEICE technical report, 108, 424, 207, 212, 28 Jan. 2009
Electro-Holography using a reflective LCD is expected as the 3-dimensional movie display technology in the future. We realized the reflective LCD Electro-Holography allowing for the wide viewing zone and visual field using the Fourier transform optical system. In addition, we estimated the size of reconstructed image, the distance for looking in both eyes, the region that place an object in our optical system theoretically. We performed the optical experiments and confirmed their results with reconstructed images., The Institute of Electronics, Information and Communication Engineers, Japanese

Recent Progress and Future Prospects of Research on Electroholography
SAKAMOTO YUJI, 視覚の科学, 29, 4, 120, 125, 26 Jan. 2009
Japanese

An Investigation of MPEG Video Scrambling with Variable Concealed Levels Considering Visual Characteristics and Its Evaluation
SAWADA Keiichi, KANG Seok, SAKAMOTO Yuji, ITE Technical Report, 32, 56, 41, 45, 11 Dec. 2008
In this paper, we propose a MPEG video scrambling method that have the ability to control the concealed level considering visual characteristics. In the proposed method, a target PSNR of the scrambled video is appointed, and the quantized DCT coefficients in I-frames are changed accodring to the target PSNR. The proposed method corrects the amount of changes considering visual characteristics, so the characteristics of the video don't influence the concealed level. In addition, the proposed method can suppress an increase of data size by restricting the range of cofficients scrambled. Subje..., The Institute of Image Information and Television Engineers, Japanese

An Investigation of MPEG Video Scrambling with Variable Concealed Levels Considering Visual Characteristics and Its Evaluation
SAWADA KEIICHI, KANG SEOK, SAKAMOTO YUJI, 情報処理学会研究報告, 2008, 124(AVM-63), 41, 45, 04 Dec. 2008
In this paper, we propose a MPEG video scrambling method that have the ability to control the concealed level considering visual characteristics. In the proposed method, a target PSNR of the scrambled video is appointed, and the quantized DCT coefficients in I-frames are changed accodring to the target PSNR. The proposed method corrects the amount of changes considering visual characteristics, so the characteristics of the video don't influence the concealed level. In addition, the proposed method can suppress an increase of data size by restricting the range of cofficients scrambled. Subjective evaluation test show that the proposed method is effective., Information Processing Society of Japan (IPSJ), Japanese

An Investigation of MPEG Video Scrambling with Variable Concealed Levels Considering Visual Characteristics and Its Evaluation
SAWADA Keiichi, KANG Seok, SAKAMOTO Yuji, IEICE technical report. Image engineering, 108, 344, 41, 45, 04 Dec. 2008
In this paper, we propose a MPEG video scrambling method that have the ability to control the concealed level considering visual characteristics. In the proposed method, a target PSNR of the scrambled video is appointed, and the quantized DCT coefficients in I-frames are changed accodring to the target PSNR. The proposed method corrects the amount of changes considering visual characteristics, so the characteristics of the video don't influence the concealed level. In addition, the proposed method can suppress an increase of data size by restricting the range of cofficients scrambled. Subje..., The Institute of Electronics, Information and Communication Engineers, Japanese

An Investigation of MPEG Video Scrambling with Variable Concealed Levels Considering Visual Characteristics and Its Evaluation
SAWADA Keiichi, KANG Seok, SAKAMOTO Yuji, IEICE technical report. Communication systems, 108, 343, 41, 45, 04 Dec. 2008
In this paper, we propose a MPEG video scrambling method that have the ability to control the concealed level considering visual characteristics. In the proposed method, a target PSNR of the scrambled video is appointed, and the quantized DCT coefficients in I-frames are changed accodring to the target PSNR. The proposed method corrects the amount of changes considering visual characteristics, so the characteristics of the video don't influence the concealed level. In addition, the proposed method can suppress an increase of data size by restricting the range of cofficients scrambled. Subje..., The Institute of Electronics, Information and Communication Engineers, Japanese

An Investigation of MPEG Video Scrambling with Variable Concealed Levels Considering Visual Characteristics and Its Evaluation
SAWADA Keiichi, KANG Seok, SAKAMOTO Yuji, IPSJ SIG Notes, 2008, 124, 41, 45, 04 Dec. 2008
In this paper, we propose a MPEG video scrambling method that have the ability to control the concealed level considering visual characteristics. In the proposed method, a target PSNR of the scrambled video is appointed, and the quantized DCT coefficients in I-frames are changed accodring to the target PSNR. The proposed method corrects the amount of changes considering visual characteristics, so the characteristics of the video don't influence the concealed level. In addition, the proposed method can suppress an increase of data size by restricting the range of cofficients scrambled. Subje..., Information Processing Society of Japan (IPSJ), Japanese

A method of synthesizing CGHs using multi-view images by spherical wave approximation
KINOSHITA MASAO, SAKAMOTO YUJI, Optics & Photonics Japan講演予稿集, 2008, 248, 249, 04 Nov. 2008
Japanese

A study of color CGH using non-Periodic color filter
IWAMI SAKI, SAKAMOTO YUJI, Optics & Photonics Japan講演予稿集, 2008, 374, 375, 04 Nov. 2008
Japanese

傾斜した物体にも対応した計算機合成ホログラムの高速計算法
坂田裕辰, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2008, ROMBUNNO.0112, 25 Oct. 2008
Japanese

セルラーオートマトンを用いた形状モーフィング
笹森新, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2008, ROMBUNNO.0221, 25 Oct. 2008
Japanese

部分主成分分析を用いた多視点画像からの任意視点画像合成
住吉信一, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2008, ROMBUNNO.0223, 25 Oct. 2008
Japanese

色彩を考慮した写真に揺らめき表現を付加した動画生成法
森智美, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2008, ROMBUNNO.0113, 25 Oct. 2008
Japanese

A Study on Animating Picture with Flicker
MORI TOMOMI, SAKAMOTO YUJI, 映像情報メディア学会技術報告, 32, 46(ME2008 162-173), 39, 42, 23 Oct. 2008
In this paper, we propose a new simple method of making animations that have motion like water surface and sunlight through foliage by adding flicker to a picture. In our method, we generate height data of surface from an original image, and, by oscillating them, make a sequence data. The luminance values are fluctuated based on these data by using bump mapping, and thus, the animations are generated. Various motion can be obtained by operating some variable numbers. For example, when we determine the amplitude by considering the initial height of near pixels, it is able to control a smoothness of motion. Additionally, when different frequencies are applied to each area of image, they move at different speed. It was revealed that it is effective in expressions like the perspective., The Institute of Image Information and Television Engineers, Japanese

A Study on Animating Picture with Flicker
Mori Tomomi, Sakamoto Yuji, ITE Technical Report, 32, 46, 39, 42, 23 Oct. 2008
In this paper, we propose a new simple method of making animations that have motion like water surface and sunlight through foliage by adding flicker to a picture. In our method, we generate height data of surface from an original image, and, by oscillating them, make a sequence data. The luminance values are fluctuated based on these data by using bump mapping, and thus, the animations are generated. Various motion can be obtained by operating some variable numbers. For example, when we determine the amplitude by considering the initial height of near pixels, it is able to control a smooth..., The Institute of Image Information and Television Engineers, Japanese

バンプマッピングを用いた写真に揺らめき表現を付加した動画生成法
森智美, 坂本雄児, 情報科学技術フォーラム, FIT 2008, 3, 283, 284, 20 Aug. 2008
Forum on Information Technology, Japanese

動きベクトルの変更による動画スクランブル技法の画質制御に関する考察
宮川健太朗, KANG Seok, 坂本雄児, 情報科学技術フォーラム, FIT 2008, 3, 249, 250, 20 Aug. 2008
Forum on Information Technology, Japanese

構造要素を用いた動的輪郭モデルによる3次元物体の輪郭抽出法
小西勇人, 坂本雄児, 情報科学技術フォーラム, FIT 2008, 3, 203, 204, 20 Aug. 2008
Forum on Information Technology, Japanese

パッチモデルを用いた計算機合成ホログラムの高速計算法
坂田裕辰, 坂本雄児, 情報科学技術フォーラム, FIT 2008, 3, 377, 378, 20 Aug. 2008
Forum on Information Technology, Japanese

I-003 Contour Extraction Method for 3D Object using Active Contour Model with Structuring Element
Konishi Hayato, Sakamoto Yuji, 情報科学技術フォーラム講演論文集, 7, 3, 203, 204, 20 Aug. 2008
Forum on Information Technology, Japanese

I-025 An Investigation of Control of Image Quality of scrambling Technique of Video by Changing Motion Vectors
Miyakawa Kentaro, Kang Seok, Sakamoto Yuji, 情報科学技術フォーラム講演論文集, 7, 3, 249, 250, 20 Aug. 2008
Forum on Information Technology, Japanese

I-042 Animating Pictures with Flicker using Bump Mapping
Mori Tomomi, Sakamoto Yuji, 情報科学技術フォーラム講演論文集, 7, 3, 283, 284, 20 Aug. 2008
Forum on Information Technology, Japanese

I-084 A Fast Calculation Method for Computer Generated Hologram Using Patch Model
Sakata Hironobu, Sakamoto Yuji, 情報科学技術フォーラム講演論文集, 7, 3, 377, 378, 20 Aug. 2008
Forum on Information Technology, Japanese

Recording Method of Multi-view Images Using Wave-Representation
SAKAMOTO YUJI, KUSHIMOTO KEI, MATSUMURA YUTAKA, 情報処理学会研究報告, 2008, 27(CVIM-162), 519, 524, 10 Mar. 2008
There are some representations method for three-dimensional light field. Here, we will discuss the wave-representation method which records the wave distribution of light. The method has advantages of adaptation for holographic three-dimensional scanner and display. However, there are problems to be solved for realization. In this paper, we discuss a transform method from multi-view images to wave-representation data. Using an appropriate hypothesis, we realize the transformation, and it is certificated by the experiments. The experiments make it clear that the wave-represention method includes informations of focal distances and continuously parallax., The Institute of Electronics, Information and Communication Engineers, Japanese

Recording Method of Multi-view Images Using Wave-Representation
Sakamoto Yuji, Kushimoto Kei, Matumura Yutaka, IPSJ SIG Notes. CVIM, 2008, 27, 519, 524, 10 Mar. 2008
There are some representations method for three-dimensional light field. Here, we will discuss the wave-representation method which records the wave distribution of light. The method has advantages of adaptation for holographic three-dimensional scanner and display. However, there are problems to be solved for realization. In this paper, we discuss a transform method from multi-view images to wave-representation data. Using an appropriate hypothesis, we realize the transformation, and it is certificated by the experiments. The experiments make it clear that the wave-represention method incl..., Information Processing Society of Japan (IPSJ), Japanese

めがね型カラーCGHにおけるカラー分割パターンの比較に関する研究
岩見早紀, 坂本雄児, 電子情報通信学会大会講演論文集, 2008, 2, 47, 47, 05 Mar. 2008
The Institute of Electronics, Information and Communication Engineers, Japanese

Blinnの反射モデルを用いたCGH計算法
山口一弘, 坂本雄児, 電子情報通信学会大会講演論文集, 2008, 2, 46, 46, 05 Mar. 2008
The Institute of Electronics, Information and Communication Engineers, Japanese

D-11-46 A Calculation Method for CGH using Blinn's Reflection Model
Yamaguchi Kazuhiro, Sakamoto Yuji, Proceedings of the IEICE General Conference, 2008, 2, 46, 46, 05 Mar. 2008
The Institute of Electronics, Information and Communication Engineers, Japanese

D-11-47 A comparative study of color separating pattern for computer-generated glasses type color hologram
Iwami Saki, Sakamoto Yuji, Proceedings of the IEICE General Conference, 2008, 2, 47, 47, 05 Mar. 2008
The Institute of Electronics, Information and Communication Engineers, Japanese

Recording Method of Multi-view Images Using Wave-Representation
SAKAMOTO YUJI, KUSHIMOTO KEI, MATSUMURA YUTAKA, 電子情報通信学会技術研究報告, 107, 538(IE2007 261-347), 519, 524, 03 Mar. 2008
Japanese

Recording Method of Multi-view Images Using Wave-Representation
Sakamoto Yuji, Kushimoto Kei, Matumura Yutaka, IEICE technical report. Image engineering, 107, 538, 519, 524, 03 Mar. 2008
There are some representations method for three-dimensional light field. Here, we will discuss the wave-representation method which records the wave distribution of light. The method has advantages of adaptation for holographic three-dimensional scanner and display. However, there are problems to be solved for realization. In this paper, we discuss a transform method from multi-view images to wave-representation data. Using an appropriate hypothesis, we realize the transformation, and it is certificated by the experiments. The experiments make it clear that the wave-represention method incl..., The Institute of Electronics, Information and Communication Engineers, Japanese

Recording Method of Multi-view Images Using Wave-Representation
Sakamoto Yuji, Kushimoto Kei, Matumura Yutaka, Technical report of IEICE. PRMU, 107, 539, 519, 524, 03 Mar. 2008
There are some representations method for three-dimensional light field. Here, we will discuss the wave-representation method which records the wave distribution of light. The method has advantages of adaptation for holographic three-dimensional scanner and display. However, there are problems to be solved for realization. In this paper, we discuss a transform method from multi-view images to wave-representation data. Using an appropriate hypothesis, we realize the transformation, and it is certificated by the experiments. The experiments make it clear that the wave-represention method incl..., The Institute of Electronics, Information and Communication Engineers, Japanese

An Investigation of Video Quality Control of MPEG Video Scrambling Considering Visual Characteristics
SAWADA KEIICHI, KANG SEOK, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 107, 487(ITS2007 62-77), 7, 11, 12 Feb. 2008
Japanese

Contour Extraction Method using Active Contour Models with Structuring Elements
KONISHI HAYATO, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 107, 487(ITS2007 62-77), 61, 65, 12 Feb. 2008
Japanese

An Investigation of Video Quality Control of MPEG Video Scrambling Considering Visual Characteristics
SAWADA Keiichi, KANG Seok, SAKAMOTO Yuji, IEICE technical report, 107, 487, 7, 11, 12 Feb. 2008
Recently, the content delivery services such as the Internet deliveries and Pay-TV have become active. However, it has not gotten the users as many as the free deliveries, and it has the problems of the piracy. Then, the methods by scrambling video data recognizably as sample data have proposed in order to get the users and protect a copyrights. However, in the previous works it is necessary to adjust the parameters interactively to control the quality of the scrambled video. Then, in this paper we propose a method that control the quality of the scrambled video by calculating the degree of..., The Institute of Electronics, Information and Communication Engineers, Japanese

Contour Extraction Method using Active Contour Models with Structuring Elements
KONISHI Hayato, SAKAMOTO Yuji, IEICE technical report, 107, 487, 61, 65, 12 Feb. 2008
To extract contour removed bumpy region from target object, a lot of method are proposed. But it is difficult to decide the parameter of bumpy length. In this paper, we propose an improved method of active contour model applied structuring method. To set structuring elements on control point, an improved method can remove a variety of bumpy region. In addition, to change the place of first contour, an improved method can change extraction of bumpy region. We report the details and availability of proposed method in this paper., The Institute of Electronics, Information and Communication Engineers, Japanese

An Investigation of Video Quality Control of MPEG Video Scrambling Considering Visual Characteristics
SAWADA Keiichi, KANG Seok, SAKAMOTO Yuji, IEICE technical report. Image engineering, 107, 489, 7, 11, 12 Feb. 2008
Recently, the content delivery services such as the Internet deliveries and Pay-TV have become active. However, it has not gotten the users as many as the free deliveries, and it has the problems of the piracy. Then, the methods by scrambling video data recognizably as sample data have proposed in order to get the users and protect a copyrights. However, in the previous works it is necessary to adjust the parameters interactively to control the quality of the scrambled video. Then, in this paper we propose a method that control the quality of the scrambled video by calculating the degree of..., The Institute of Electronics, Information and Communication Engineers, Japanese

Contour Extraction Method using Active Contour Models with Structuring Elements
KONISHI Hayato, SAKAMOTO Yuji, IEICE technical report. Image engineering, 107, 489, 61, 65, 12 Feb. 2008
To extract contour removed bumpy region from target object, a lot of method are proposed. But it is difficult to decide the parameter of bumpy length. In this paper, we propose an improved method of active contour model applied structuring method. To set structuring elements on control point, an improved method can remove a variety of bumpy region. In addition, to change the place of first contour, an improved method can change extraction of bumpy region. We report the details and availability of proposed method in this paper., The Institute of Electronics, Information and Communication Engineers, Japanese

An investigation of video quality control of MPEG video scrambling considering visual characteristics
澤田 圭一, 姜 錫, 坂本 雄児, ITE technical report, 32, 10, 7, 11, Feb. 2008
映像情報メディア学会, Japanese

Contour extraction method using active contour models with structuring elements
小西 勇人, 坂本 雄児, ITE technical report, 32, 10, 61, 65, Feb. 2008
映像情報メディア学会, Japanese

Synthesis of arbitrary viewpoint image from images of multiple weakly calibrated camera images using all in-focus rendering method
Yutaka Matsumura, Yuji Sakamoto, THREE-DIMENSIONAL IMAGE CAPTURE AND APPLICATIONS 2008, 6805, 680510.1-680510.12, 2008
We describe a. method that synthesizes a high-quality arbitrary-viewpoint image from multiple weakly-calibrated cameras. We reconstructed the approximate shape of the object reconstructed by the shape from silhouette method on a projective grid space(PGS). However, the distortion is caused in the synthesized image by the difference with the actual object and the approximate shape. In particular, the distortion is caused by a concave region. Our method synthesizes the arbitrary-viewpoint image with a little distortion by revising a depthmap obtained from the approximate shape. The depthmap is revised by using the all in-focus rendering method that makes light field rendering expand. When all camera parameters were uncalibrated, we could not apply this rendering method. Our method enabled applying uncalibrated cameras using the all in-focus rendering method by calculating each camera parameter on the PGS. We demonstrate the effectiveness of the method with arbitrary-viewpoint images and real images that were taken from multiple uncalibrated cameras., SPIE-INT SOC OPTICAL ENGINEERING, English

An Investigation of an Embedding Technique of Fingerprint data into Sound Data using Fuzzy Vault
LEE JAEHEE, KANG SEOK, SAKAMOTO YUJI, 情報処理学会研究報告, 2007, 125(AVM-59), 13, 17, 13 Dec. 2007
An investigation of an Embedding Technique of Fingerprint data into Sound Data using Fuzzy Vault., Information Processing Society of Japan (IPSJ), Japanese

An Investigation of an Embedding Technique of Fingerprint data into Sound Data using Fuzzy Vault
Lee JaeHee, Kang Seok, Sakamoto Yuji, IPSJ SIG Notes, 2007, 125, 13, 17, 13 Dec. 2007
An investigation of an Embedding Technique of Fingerprint data into Sound Data using Fuzzy Vault., Information Processing Society of Japan (IPSJ), Japanese

An Investigation of an Embedding Technique of Fingerprint data into Sound Data using Fuzzy Vault
Lee JaeHee, Kang Seok, Sakamoto Yuji, IEICE technical report. Image engineering, 107, 380, 13, 17, 06 Dec. 2007
An investigation of an Embedding Technique of Fingerprint data into Sound Data using Fuzzy Vault., The Institute of Electronics, Information and Communication Engineers, Japanese

An Investigation of an Embedding Technique of Fingerprint data into Sound Data using Fuzzy Vault
Lee JaeHee, Kang Seok, Sakamoto Yuji, IEICE technical report. Communication systems, 107, 379, 13, 17, 06 Dec. 2007
An investigation of an Embedding Technique of Fingerprint data into Sound Data using Fuzzy Vault., The Institute of Electronics, Information and Communication Engineers, Japanese

An investigation of an embedding technique of fingerprint data into sound data using fuzzy vault
李 在煕, 姜 錫, 坂本 雄児, ITE technical report, 31, 64, 13, 17, Dec. 2007
映像情報メディア学会, Japanese

色差楕円を用いたグレーティング型レインボーホログラムにおける色変化
村田聡司, 坂本雄児, 映像情報メディア学会冬季大会講演予稿集(CD-ROM), 2007, ROMBUNNO.1-8, 27 Nov. 2007
Japanese

1-8 Color change in a grating type rainbow hologram that uses color-difference ellipsoids
Murata Satoshi, Sakamoto Yuji, ITE Winter Annual Convention, 0, 2007, "1, 8-1", 27 Nov. 2007
The color of the reconstructed images of a grating type rainbow hologram change as viewing position changing. In this paper, we propose a method that the color change is minimized using color-difference ellipsoids. Additionally, the efficiency was verified by optical experiments., The Institute of Image Information and Television Engineers, Japanese

めがね型カラーCGHに関する研究
岩見早紀, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2007, ROMBUNNO.204, 27 Oct. 2007
Japanese

色変化の少ないグレーティング型レインボーホログラム
村田聡司, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2007, ROMBUNNO.202, 27 Oct. 2007
Japanese

凹領域を除く輪郭抽出手法に関する研究
小西勇人, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2007, ROMBUNNO.214, 27 Oct. 2007
Japanese

表面反射特性を考慮した計算機合成ホログラムに関する研究
山口一弘, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2007, ROMBUNNO.203, 27 Oct. 2007
Japanese

柔軟な視点設定を持つグレーティング型ホログラム
木下政雄, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2007, ROMBUNNO.205, 27 Oct. 2007
Japanese

Examination of Watermarking Method Using Moire Patterns
MIYOSHI KUNIHIKO, KANG SEOK, SAKAMOTO YUJI, 電気学会通信研究会資料, CMN-07, 27-60, 51, 55, 27 Sep. 2007
Japanese

Synthesis of Arbitrary-Viewpoint Image with a little Distortion Using All in-Focus Rendering Method from Multiple Weekly-Calibrated Cameras
MATSUMURA YUTAKA, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 107, 242(MVE2007 37-59), 127, 132, 27 Sep. 2007
At present, the various methods to synthesize an arbitrary-viewpoint image from multiple weekly-calibrated cameras using Projective Grid Space (PGS) are studied. The approximate shape of the object is generally used, but there is a problem that a Distortion is caused to a generated image by the difference with the actual object. In this paper, we proposed the method to synthesize the arbitrary-viewpoint image with a little distortion by by revising the approximate shape of the object using all in-focus rendering method that is the method which made light field theory expands., The Institute of Electronics, Information and Communication Engineers, Japanese

Examination of Watermarking Method Using Moire Patterns
MIYOSHI Kunihiko, KANG Seok, SAKAMOTO Yuji, 電気学会研究会資料. CMN, 通信研究会, 2007, 27, 51, 56, 27 Sep. 2007
Japanese

Synthesis of Arbitrary-Viewpoint Image with a little Distortion Using All in-Focus Rendering Method from Multiple Weekly-Calibrated Cameras
MATSUMURA Yutaka, SAKAMOTO Yuji, Technical report of IEICE. Multimedia and virtual environment, 107, 242, 127, 132, 27 Sep. 2007
At present, the various methods to synthesize an arbitrary-viewpoint image from multiple weekly-calibrated cameras using Projective Grid Space (PGS) are studied. The approximate shape of the object is generally used, but there is a problem that a Distortion is caused to a generated image by the difference with the actual object. In this paper, we proposed the method to synthesize the arbitrary-viewpoint image with a little distortion by by revising the approximate shape of the object using all in-focus rendering method that is the method which made light field theory expands., The Institute of Electronics, Information and Communication Engineers, Japanese

Examination of Watermarking Method Using Moire Patterns
MIYOSHI Kunihiko, KANG Seok, SAKAMOTO Yuji, IEICE technical report. Office Information Systems, 107, 230, 51, 55, 20 Sep. 2007
By the spread of the digital camera and the information infrastructure, many objects of shooting came to be circulated easily as digital photographs. Therefore, how rights of the copyright and the property right, etc. included in object are protected becomes a problem. We proposes the digital watermarking method using moire pattern as one of the solutions. This method protects the rights from digital photography by causing moire pattern in photographs in consideration of the specification of the object distance and the camera. This paper treats about the outline of this watermarking method ..., The Institute of Electronics, Information and Communication Engineers, Japanese

Examination of Watermarking Method Using Moire Patterns
MIYOSHI Kunihiko, KANG Seok, SAKAMOTO Yuji, IEICE technical report. Image engineering, 107, 231, 51, 55, 20 Sep. 2007
By the spread of the digital camera and the information infrastructure, many objects of shooting came to be circulated easily as digital photographs. Therefore, how rights of the copyright and the property right, etc. included in object are protected becomes a problem. We proposes the digital watermarking method using moire pattern as one of the solutions. This method protects the rights from digital photography by causing moire pattern in photographs in consideration of the specification of the object distance and the camera. This paper treats about the outline of this watermarking method ..., The Institute of Electronics, Information and Communication Engineers, Japanese

Examination of Watermarking Method Using Moire Patterns
MIYOSHI Kunihiko, KANG Seok, SAKAMOTO Yuji, Technical report of IEICE. CQ, 107, 229, 51, 55, 20 Sep. 2007
By the spread of the digital camera and the information infrastructure, many objects of shooting came to be circulated easily as digital photographs. Therefore, how rights of the copyright and the property right, etc. included in object are protected becomes a problem. We proposes the digital watermarking method using moire pattern as one of the solutions. This method protects the rights from digital photography by causing moire pattern in photographs in consideration of the specification of the object distance and the camera. This paper treats about the outline of this watermarking method ..., The Institute of Electronics, Information and Communication Engineers, Japanese

Examination of watermarking method using moire patterns
三好 邦彦, 姜 錫, 坂本 雄児, ITE technical report, 31, 42, 51, 55, Sep. 2007
映像情報メディア学会, Japanese

LCDを用いた分割表示による視野拡大CGH再生システム
矢部義明, 永井利明, 坂本雄児, 3次元画像コンファレンス講演論文集, 2007, 9, 12, Jul. 2007
Japanese

超多眼ディスプレイと電子ホログラフィックディスプレイの分解能をパラメータとした画素数の比較
坂本雄児, 3次元画像コンファレンス講演論文集, 2007, 196, 199, Jul. 2007
Japanese

画像への応用を考慮したグレーティング型レインボーホログラムのスペクトル選択法
浅野宏行, 坂本雄児, 日本分光学会講演要旨集, 2006, 282, 283, 08 Nov. 2006
Japanese

EPI上の対応点軌跡を用いたラグランジュ補間による光線データ補間
松村豊, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2006, ROMBUNNO.227, 28 Oct. 2006
Japanese

モアレを利用した電子透かし技法に関する検討
三好邦彦, 姜錫, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2006, ROMBUNNO.207, 28 Oct. 2006
Japanese

グレーティング型レインボーホログラムにおけるスペクトル多色選択の比較,検討
浅野宏行, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2006, ROMBUNNO.224, 28 Oct. 2006
Japanese

分割表示による計算機合成ホログラムの視野拡大
矢部義明, 永井利明, 坂本雄児, 電気・情報関係学会北海道支部連合大会講演論文集(CD-ROM), 2006, ROMBUNNO.225, 28 Oct. 2006
Japanese

多視点画像から波面記述データへの変換とホログラム化の検討
久志本圭, 坂本雄児, HODIC Circ, 26, 3, 9, 12, 08 Sep. 2006
Japanese

Transformation from Multi-View Images to Data of the Light Wave Representation and Making Holograms
KUSHIMOTO Kei, SAKAMOTO Yuji, ITE technical report, 30, 43, 7, 10, 08 Sep. 2006
映像情報メディア学会, Japanese

Shape morphing by using sphere-filling
KADOSHIMA HIROTAKA, SAKAMOTO YUJI, 画像電子学会研究会講演予稿, 226th, 77, 80, 28 Jul. 2006
Japanese

High luminance grating-type rainbow holograms by spectrum choice
ASANO HIROYUKI, SAKAMOTO YUJI, 画像電子学会研究会講演予稿, 226th, 49, 52, 28 Jul. 2006
Japanese

スペクトル選択によるグレーティング型レインボーホログラムの高輝度化
浅野 宏行, 坂本 雄児, 研究会講演予稿, 226, 0, 49, 52, 28 Jul. 2006
画像電子学会, Japanese

球充填を用いた形状モーフィング
角島 大貴, 坂本 雄児, 研究会講演予稿, 226, 0, 77, 80, 28 Jul. 2006
画像電子学会, Japanese

High luminance grating-type rainbow holograms by spectrum choice
ASANO Hiroyuki, SAKAMOTO Yuji, ITE technical report, 30, 41, 49, 52, 28 Jul. 2006
映像情報メディア学会, Japanese

Shape morphing by using sphere-filling
KADOSHIMA Hirotaka, SAKAMOTO Yuji, ITE technical report, 30, 41, 77, 80, 28 Jul. 2006
映像情報メディア学会, Japanese

バブルメッシュを利用した形状モーフィング
角島大貴, 坂本雄児, 電子情報通信学会大会講演論文集, 2006, 2, 100, 100, 08 Mar. 2006
The Institute of Electronics, Information and Communication Engineers, Japanese

電子ホログラフィにおける視野・視域拡大の検討
永井利明, 坂本雄児, 電子情報通信学会大会講演論文集, 2006, 2, 51, 51, 08 Mar. 2006
The Institute of Electronics, Information and Communication Engineers, Japanese

D-11-51 An Examination of Enlargement of Visual Field and Viewing Zone for Electro-Holography
Nagai Toshiaki, Sakamoto Yuji, Proceedings of the IEICE General Conference, 2006, 2, 51, 51, 08 Mar. 2006
The Institute of Electronics, Information and Communication Engineers, Japanese

D-11-100 Shape Morphing using Bubble Mesh
Kadoshima Hirotaka, Sakamoto Yuji, Proceedings of the IEICE General Conference, 2006, 2, 100, 100, 08 Mar. 2006
The Institute of Electronics, Information and Communication Engineers, Japanese

An Investigation of Emphasis of Hairstyles in Comic Portraits
YOSHIZAWA Yuuki, SAKAMOTO Yuji, 映像情報メディア学会技術報告, 30, 14, 121, 126, 21 Feb. 2006
Japanese

An Investigation of Emphasis of Hairstyles in Comic Portraits
YOSHIZAWA YUKI, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 105, 609(ITS2005 79-109), 121, 126, 14 Feb. 2006
Japanese

An Investigation of Emphasis of Hairstyles in Comic Portraits
YOSHlZAWA Yuuki, SAKAMOTO Yuji, IEICE technical report, 105, 609, 121, 126, 14 Feb. 2006
A portrait expresses the feature of an individual face directly. It is easy to distinguish the avatar created from the portrait from other avatars, because it becomes each human's thing. And we can have attachment to the avatar. If the avatar is a comic portrait, the exaggeration of expression and the comical mark of feeling can be used without sense of incongruity. Therefore, we can use various feeling expression on the communication using avatars. Although a hairstyle expresses the individual feature well in a portrait, but expression is difficult because individual difference is large an..., The Institute of Electronics, Information and Communication Engineers, Japanese

A fast method for generating views of unfolded stomach
MASUI DAISUKE, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 105, 579(MI2005 66-107), 155, 158, 20 Jan. 2006
In this paper, we propose the fast method for generating the approximated shape, from which unfolded view is generated, using morphological operation. Conventionally, there was a problem that not only the folds but also the gastric angle, which is a part of the stomach wall shape, are removed by the morphological operation using a spherical structure element. Then, we appropriately remove only folds by using the structure element having special shape. In addition, we attain speed-up of processing by using a part on the spherical surface for a structure element. Applying proposed method for an abdominal CT image, we generated an approximated shape successfully, and the processing speed increased to 242 times of that of conventional method., The Institute of Electronics, Information and Communication Engineers, Japanese

Study on the Environmental Creation for TIP
MATSUNO ATSUSHI, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 105, 566(MVE2005 56-68), 69, 74, 19 Jan. 2006
TIP is the one of Image-based Technology which reconstruct 3D object from 2D image, can create 3D space from only a single 2D image. But, because there is no information of the background that occluded by foreground object and that of the backside of the foreground object, the user must make it. And, there are the images that have no information of the side and top face. In this paper, the backside and the side are created by searching for the most similar region in input image. As a result, the user can move freely in the 3D space., The Institute of Electronics, Information and Communication Engineers, Japanese

電子ホログラフィの広視野・視域化
永井利明, 矢部義明, 坂本雄児, 3次元画像コンファレンス講演論文集, 2006(CD-ROM), ROMBUNNO.6-2, 2006
Japanese

円筒形計算機合成ホログラムにおける計算の高速化
柏木暁史, 坂本雄児, 3次元画像コンファレンス講演論文集, 2006(CD-ROM), ROMBUNNO.6-3, 2006
Japanese

電子ホログラフィにおける画質の改善--空間周波数フィルタリング法を用いた二重像除去
坂本 雄児, 画像ラボ, 16, 12, 13, 16, Dec. 2005
日本工業出版, Japanese

時分割多重による電子ホログラフィックディスプレイの基礎研究
坂本雄児, HODIC Circ, 25, 4, 18, 22, 18 Nov. 2005
Japanese

電子ホログラフィにおける視域・視野の拡大
坂本雄児, 情報科学技術フォーラム, FIT 2005, 205, 206, 22 Aug. 2005
Japanese

腹部X線CT像における胃壁ひだ領域の強調表示
増井大祐, 坂本雄児, 情報科学技術フォーラム, FIT 2005, 2, 363, 364, 22 Aug. 2005
Forum on Information Technology, Japanese

H-028 Emphasis and Visualization of Stomach Fold Regions in Abdominal X-ray CT Images
Masui Daisuke, Sakamoto Yuji, 情報科学技術フォーラム一般講演論文集, 4, 2, 363, 364, 22 Aug. 2005
Forum on Information Technology, Japanese

J-014 Enlargement of Viewing-zones and Visual-fields in Electro-holography
Sakamoto Yuji, 情報科学技術フォーラム一般講演論文集, 4, 3, 205, 206, 22 Aug. 2005
Forum on Information Technology, Japanese

円筒形記録面による波面記述法
坂本雄児, 電子情報通信学会大会講演論文集, 2005, 81, 81, 07 Mar. 2005
The Institute of Electronics, Information and Communication Engineers, Japanese

D-11-81 The Wave Representation Recording in a Cylindrical Surface
Sakamoto Yuji, Proceedings of the IEICE General Conference, 2005, 2, 81, 81, 07 Mar. 2005
The Institute of Electronics, Information and Communication Engineers, Japanese

腹部X線CT像からの胃壁ひだ領域の抽出・強調
増井大祐, 坂本雄児, 青木由直, 映像情報メディア学会冬季大会講演予稿集(CD-ROM), 2004, 10, 3, 03 Dec. 2004
Japanese

計算機合成ホログラムによる医用画像の立体表示
坂本雄児, HODIC Circ, 24, 3, 10, 13, 10 Sep. 2004
Japanese

Autosteroscopic Displaying of 3-D medical images using CGH
SAKAMOTO Yuji, ITE technical report, 28, 50, 9, 12, 10 Sep. 2004
映像情報メディア学会, Japanese

波面記述による3次元空間情報の記録
坂本雄児, 情報科学技術フォーラム, FIT 2004, 305, 306, 20 Aug. 2004
Japanese

階層型3次元可逆画像圧縮による医用画像の伝送
明上山温, 坂本雄児, 松島恭治, 情報科学技術フォーラム, FIT 2004, 2, 441, 442, 20 Aug. 2004
Forum on Information Technology, Japanese

H-017 Medical Image Transmission Using 3D Hierarchical lossless image compression
Myojyoyama Atsushi, Sakamoto Yuji, Matsushima Kyoji, 情報科学技術フォーラム一般講演論文集, 3, 2, 441, 442, 20 Aug. 2004
Forum on Information Technology, Japanese

J-044 Recording of 3D Spatial Information using Wave Representation
Sakamoto Yuji, 情報科学技術フォーラム一般講演論文集, 3, 3, 305, 306, 20 Aug. 2004
Forum on Information Technology, Japanese

3次元医療画像の計算機合成ホログラムによる立体表示
坂本雄児, 松島恭治, 明上山温, 3次元画像コンファレンス講演論文集, 2004, 123, 126, Jun. 2004
Japanese

計算機合成円筒形状ホログラムにおける広い角度への伝搬計算
飛世昌昭, 坂本雄児, 青木由直, 3次元画像コンファレンス講演論文集, 2004, 115, 118, Jun. 2004
Japanese

計算機合成ホログラムにおける金属反射モデル
鶴野敦士, 坂本雄児, 青木由直, 電子情報通信学会大会講演論文集, 2004, 2, 158, 158, 08 Mar. 2004
The Institute of Electronics, Information and Communication Engineers, Japanese

計算機合成ホログラムによる医用画像の立体表示
坂本雄児, 電子情報通信学会大会講演論文集, 2004, 161, 08 Mar. 2004
Japanese

D-11-158 A Metallic Reflection Model of Computer Generated Hologram
Tsuruno Atsushi, Sakamoto Yuji, Aoki Yoshinao, Proceedings of the IEICE General Conference, 2004, 2, 158, 158, 08 Mar. 2004
The Institute of Electronics, Information and Communication Engineers, Japanese

D-11-161 Three dimensional displaying of medical imaginary using computer generated hologram
SAKAMOTO Yuji, Proceedings of the IEICE General Conference, 2004, 2, 161, 161, 08 Mar. 2004
The Institute of Electronics, Information and Communication Engineers, Japanese

CD-Rディスクによる立体画像表示--少量多品種な計算機合成ホログラムの作成を目指して
坂本 雄児, 森島 守人, 臼井 章, 画像ラボ, 15, 1, 17, 20, Jan. 2004
日本工業出版, Japanese

CD‐Rディスクへの計算機合成ホログラムの描画
坂本雄児, HODIC Circ, 23, 4, 13, 16, 14 Nov. 2003
Japanese

計算機合成ホログラムにおける光の屈折を考慮した透明物体の表現法
金沢圭晃, 坂本雄児, 青木由直, 情報科学技術フォーラム, FIT 2003, 391, 392, 25 Aug. 2003
Japanese

物体面における反射・透過及び影を考慮した計算機合成ホログラムの生成法
江面和哉, 坂本雄児, 青木由直, 情報科学技術フォーラム, FIT 2003, 389, 390, 25 Aug. 2003
Japanese

光学的3次元空間情報の2次元記述法
坂本雄児, 情報科学技術フォーラム, FIT 2003, 287, 288, 25 Aug. 2003
Japanese

計算機合成円筒形状ホログラム
飛世昌昭, 坂本雄児, 青木由直, 情報科学技術フォーラム, FIT 2003, 393, 394, 25 Aug. 2003
Japanese

デスクトップ・ディジタル・ホログラミング
坂本雄児, 森島守人, 臼井章, 3次元画像コンファレンス講演論文集, 2003, 157, 160, 01 Jul. 2003
Japanese

An Object-Light Calculation Method Considering Shadow, Reflection, and Penetration of Lights for Computer-Generated Holograms
EZURA KAZUYA, SAKAMOTO YUJI, AOKI YOSHINAO, 画像電子学会研究会講演予稿, 200th, 129, 134, 10 Mar. 2003
Japanese

計算機合成ホログラムにおける光の影・反射・透過を考慮した物体光計算法
江面 和哉, 坂本 雄児, 青木 由直, 研究会講演予稿, 200, 0, 129, 134, 10 Mar. 2003
画像電子学会, Japanese

計算機合成ホログラムを用いたCD‐Rによる立体像表示
坂本雄児, 森島守人, 臼井章, 電子情報通信学会大会講演論文集, 2003, 2, 146, 146, 03 Mar. 2003
The Institute of Electronics, Information and Communication Engineers, Japanese

Autostereoscopic Displaying on CD-R Using by Computer-Generated Hologram
Sakamoto Yuji, Morishima Morito, Usui Akira, Proceedings of the IEICE General Conference, 2003, 2, 146, 146, 03 Mar. 2003
The Institute of Electronics, Information and Communication Engineers, Japanese

計算機合成ホログラムによるボリュームデータの立体画像化
坂本雄児, 金沢圭晃, 青木由直, 3次元画像コンファレンス講演論文集, 2002, 209, 212, 04 Jul. 2002
Japanese

Back‐to‐FrontアルゴリズムによるCGHレンダリング法
坂本雄児, 電子情報通信学会大会講演論文集, 2002, 151, 07 Mar. 2002
Japanese

Rendering Method for CGH Using Back-to-Front Algorithm
Sakamoto Yuji, Proceedings of the IEICE General Conference, 2002, 2, 07 Mar. 2002
Institute of Electronics, Information, and Communication Engineers, Japanese

A Fast Computational Method for Computer Generated Fourier Hologram Using Patch Model
SAKAMOTO Yuji, NAGAO Tomohiro, IEICE transactions on electronics, 85, 3, 863, 863, 01 Mar. 2002
It takes long time to calculate computer generated hologram due to a large amount of computation for light difraction of object light. In this paper, we propose a new fast algorithm for object-light calculation using patch model for computer generated Fourier hologram. The precalculated fringe pattern from a basic patch is transformed to one of each patch by slide & rotation, distance, slanting and magnification transforms. The results of computer simulation and optical experiments show that the transforms are applied to computer generated hologram successfully and the method is about 60 times faster than traditional method., The Institute of Electronics, Information and Communication Engineers, English

Hidden surface removal method with Z-Buffer in computer generated holograms.
TAKASE MASAFUMI, SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会技術研究報告, 101, 626(IE2001 172-189), 1, 6, 29 Jan. 2002
ln computer-generated holograms, description for object model is important to achieve high quality reproduced-image. In this paper, we propose new algorithm for hidden surface removal method of computer erenerated holograms using Z-Buffer that is generally used in computer eraohics. The result of ootical exoeriments show that the method is applied to comouter generated holograms., The Institute of Image Information and Television Engineers, Japanese

Volume-Rendering Method for Computer-Generated-Holograms.
AOYAMA TAKESHI, SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会技術研究報告, 101, 626(IE2001 172-189), 7, 12, 29 Jan. 2002
Japanese

Hidden surface removal method with Z-Buffer in computer generated holograms
TAKASE Masafumi, SAKAMOTO Yuji, AOKI Yoshinao, ITE Technical Report, 26, 8, 1, 6, 29 Jan. 2002
ln computer-generated holograms, description for object model is important to achieve high quality reproduced-image. In this paper, we propose new algorithm for hidden surface removal method of computer erenerated holograms using Z-Buffer that is generally used in computer eraohics. The result of ootical exoeriments show that the method is applied to comouter generated holograms., The Institute of Image Information and Television Engineers, Japanese

Volume-Rendering Method for Computer-Generated-Holograms
AOYAMA Takeshi, SAKAMOTO Yuji, AOKI Yoshinao, ITE Technical Report, 26, 8, 7, 12, 29 Jan. 2002
Recently, it is oossible to get realistic images from three-dimensional data of CT or MRl using by volume rendering method. To use of stereoscopic display, it becomes more easily to recoenize of three-dimensional structures of objects. ln this paper, we propose a new rendering method of computer-generated hologram using volume rendering method. The method provides direct calculation of hologram data from three-dimensional data without intermediate processing., The Institute of Image Information and Television Engineers, Japanese

Hidden surface removal method with Z-Buffer in computer generated holograms
TAKASE Masafumi, SAKAMOTO Yuji, AOKI Yoshinao, 電子情報通信学会技術研究報告. ITS, 101, 624, 1, 6, 22 Jan. 2002
In computer-generated holograms, description for object model is important to achieve high quality reproduced-image. In this paper, we propose new algorithm for hidden surface removal method of computer generated holograms using Z-Buffer that is generally used in computer graphics. The result of optical experiments show that the method is applied to computer generated holograms., The Institute of Electronics, Information and Communication Engineers, Japanese

Volume-Rendering Method for Computer-Generated-Holograms
AOYAMA Takeshi, SAKAMOTO Yuji, AOKI Yoshinao, ITE Technical Report, 101, 624, 7, 12, 22 Jan. 2002
Recently, it is possible to get realistic images from three-dimensional data of CT or MRI using by volume rendering method. To use of stereoscopic display, it becomes more easily to recognize of three-dimensional structures of objects. In this paper, we propose a new rendering method of computer-generated hologram using volume rendering method. The method provides direct calculation of hologram data from three-dimensional data without intermediate processing., The Institute of Electronics, Information and Communication Engineers, Japanese

Hidden surface removal method with Z-Buffer in computer generated holograms
Takase Masafumi, Sakamoto Yuji, Aoki Yoshinao, IEICE technical report. Image engineering, 101, 626, 1, 6, 22 Jan. 2002
In computer-generated holograms, description for object model is important to achieve high quality reproduced-image. In this paper, we propose new algorithm for hidden surface removal method of computer generated holograms using Z-Buffer that is generally used in computer graphics. The result of optical experiments show that the method is applied to computer generated holograms., The Institute of Electronics, Information and Communication Engineers, Japanese

Volume-Rendering Method for Computer-Generated-Holograms
Aoyama Takeshi, Sakamoto Yuji, Aoki Yoshinao, IEICE technical report. Image engineering, 101, 626, 7, 12, 22 Jan. 2002
Recently, it is possible to get realistic images from three-dimensional data of CT or MRI using by volume rendering method. To use of stereoscopic display, it becomes more easily to recognize of three-dimensional structures of objects. In this paper, we propose a new rendering method of computer-generated hologram using volume rendering method. The method provides direct calculation of hologram data from three-dimensional data without intermediate processing., The Institute of Electronics, Information and Communication Engineers, Japanese

ボリュームデータからの計算機合成ホログラム作成
青山丈志, 坂本雄児, 青木由直, 電子情報通信学会大会講演論文集, 2001, 151, 151, 29 Aug. 2001
The Institute of Electronics, Information and Communication Engineers, Japanese

計算機ホログラムにおける影伝搬法を用いた隠面消去法
坂本雄児, 青木由直, 電子情報通信学会大会講演論文集, 2001, 148, 148, 29 Aug. 2001
The Institute of Electronics, Information and Communication Engineers, Japanese

Hidden Surface Removal Using Shadow Propagation Method for Computer Hologram
Sakamoto Yuji, Aoki Yoshinao, Proceedings of the Society Conference of IEICE, 2001, 0, 148, 148, 29 Aug. 2001
The Institute of Electronics, Information and Communication Engineers, Japanese

Computer Generated Hologram from Volume Data
Aoyama Takeshi, Sakamoto Yuji, Aoki Yoshinao, Proceedings of the Society Conference of IEICE, 2001, 0, 151, 151, 29 Aug. 2001
The Institute of Electronics, Information and Communication Engineers, Japanese

基本平面モデルによる計算機合成ホログラム
坂本雄児, 3次元画像コンファレンス講演論文集, 2001, 5, 8, 04 Jul. 2001
Japanese

階層型ソートを用いた画像の可逆符号化
明上山温, 坂本雄児, 山本強, 電子情報通信学会大会講演論文集, 2001, 2, 24, 24, 07 Mar. 2001
The Institute of Electronics, Information and Communication Engineers, Japanese

フレネル領域でのポリゴンモデルよりの計算機ホログラム高速計算法
坂本雄児, 長尾智宏, 青木由直, 電子情報通信学会大会講演論文集, 2001, 2, 123, 123, 07 Mar. 2001
The Institute of Electronics, Information and Communication Engineers, Japanese

lossless image coding using hierarchical sort
MYOJOYAMA Atsushi, SAKAMOTO Yuji, YAMAMOTO Tsuyoshi, Proceedings of the IEICE General Conference, 2001, 2, 24, 24, 07 Mar. 2001
The Institute of Electronics, Information and Communication Engineers, Japanese

A Fast Calculation Method for Computer Generated Hologram Using Polygon Model in Fresnel Region
Sakamoto Yuji, Nagao Tomohiro, Aoki Yoshinao, Proceedings of the IEICE General Conference, 2001, 2, 123, 123, 07 Mar. 2001
The Institute of Electronics, Information and Communication Engineers, Japanese

Fast Generation Method of Computer-Generated Holograms Using Polygon-Model.
NAGAO TOMOHIRO, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 100, 607(IE2000 155-168), 37, 42, 31 Jan. 2001
Japanese

Fast Generation Method of Computer-Generated Holograms Using Polygon-Model
NAGAO Tomohiro, SAKAMOTO Yuji, ITE Technical Report, 25, 9, 37, 42, 31 Jan. 2001
Computer Generated Holograms (CGH) has the potential to produce three-dimensional images for the principle of 3-D display. However, it is necessary to develop a fast computing method, because it takes a lot of time to calculate the holographic pattems. We present a new method for computing the pattems from object description by Polygon-Model at high speed. The rendering algorithm provides the holographic pattem by composing a sequence of object light that was rendered a basis polygon in advance. We achieved more 1000 times faster than a conventional method., The Institute of Image Information and Television Engineers, Japanese

Fast Generation Method of Computer-Generated Holograms Using Polygon-Model
NAGAO Tomohiro, SAKAMOTO Yuji, IEICE technical report. Image engineering, 100, 607, 37, 42, 24 Jan. 2001
Computer Generated Holograms(CGH) has the potential to produce three-dimensional images for the principle of 3-D display. However, it is necessary to develop a fast computing method, because it takes a lot of time to calculate the holographic pattems. We present a new method for computing the pattems from object description by Polygon-Model at high speed. The rendering algorithm provides the holographic pattem by composing a sequence of object light that was rendered a basis polygon in advance. We achieved more 1000 times faster than a conventional method., The Institute of Electronics, Information and Communication Engineers, Japanese

Fast Generation Method of Computer-Generated Holograms Using Polygon-Model
NAGAO Tomohiro, SAKAMOTO Yuji, IEICE technical report. Electronic information displays, 100, 605, 37, 42, 24 Jan. 2001
Computer Generated Holograms (CGH) has the potential to produce three-dimensional images for the principle of 3-D display. However, it is necessary to develop a fast computing method, because it takes a lot of time to calculate the holographic pattems. We present a new method for computing the pattems from object description by Polygon-Model at high speed. The rendering algorithm provides the holographic pattem by composing a sequence of object light that was rendered a basis polygon in advance. We achieved more 1000 times faster than a conventional method., The Institute of Electronics, Information and Communication Engineers, Japanese

Lossless image coding considered characteristics of medical image.
MEIJOYAMA ATSUSHI, SAKAMOTO YUJI, YAMAMOTO TSUYOSHI, 電子情報通信学会技術研究報告, 100, 287(MI2000 31-37), 1, 5, 14 Sep. 2000
Japanese

線形メディア変換を用いた感情通信システムの試み
坂本雄児, 棚橋真, 青木由直, 電子情報通信学会大会講演論文集, 2000, 100, 100, 07 Sep. 2000
The Institute of Electronics, Information and Communication Engineers, Japanese

物体光の変換による計算機合成ホログラム生成の高速化
長尾智大, 坂本雄児, 電子情報通信学会大会講演論文集, 2000, 178, 178, 07 Sep. 2000
The Institute of Electronics, Information and Communication Engineers, Japanese

線形メディア変換による感情通信システムの実装の検討
棚橋真, 坂本雄児, 青木由直, 電子情報通信学会大会講演論文集, 2000, 101, 101, 07 Sep. 2000
The Institute of Electronics, Information and Communication Engineers, Japanese

ばねモデルによる接合領域分割法
高橋宏卓, 坂本雄児, 電子情報通信学会大会講演論文集, 2000, 306, 306, 07 Sep. 2000
The Institute of Electronics, Information and Communication Engineers, Japanese

Lossless image coding considered characteristics of medical image
Myojoyama Atsushi, Sakamoto Yuji, Yamamoto Tsutoshi, IEICE technical report., 100, 287, 1, 5, 07 Sep. 2000
We introduce a new lossless coding method for gray scale images based on hierarchical sort. Hierarchical sort is a sorting algorithm for image codings using block segmentation and it makes code size of predictive coding in each block compact. Comparison using experimental implementation of the method shows better compression ratio than conventional methods for high resolution images and highly correlated image set such as X ray CT images. This method supports progressive decoding and fast preview of large image., The Institute of Electronics, Information and Communication Engineers, Japanese

Segmentation method for boundary using mass-spring model
TAKAHASHI Koutaku, SAKAMOTO Yuuji, Proceedings of the Society Conference of IEICE, 2000, 0, 306, 306, 07 Sep. 2000
The Institute of Electronics, Information and Communication Engineers, Japanese

Study of Emotional Communication Systems using Linear Media Translations
SAKAMOTO Yuji, TANAHASHI Shin, AOKI Yoshinao, Proceedings of the Society Conference of IEICE, 2000, 0, 100, 100, 07 Sep. 2000
The Institute of Electronics, Information and Communication Engineers, Japanese

Development of Emotional Communication Systems using Linear Media Traslations
TANAHASHI Shin, SAKAMOTO Yuji, AOKI Yoshinao, Proceedings of the Society Conference of IEICE, 2000, 0, 101, 101, 07 Sep. 2000
The Institute of Electronics, Information and Communication Engineers, Japanese

Fast Generation Method of Computer-Generated Holograms Using Translatio of Object Light
NAGAO Tomohiro, SAKAMOTO Yuji, Proceedings of the Society Conference of IEICE, 2000, 0, 178, 178, 07 Sep. 2000
The Institute of Electronics, Information and Communication Engineers, Japanese

The Optimization to Noisy Environments Using Genetic Programming.
YOSHIDA KOSUKE, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 100, 88(AI2000 1-9), 37, 44, 25 May 2000
Japanese

The Optimization to Noisy Environments Using Genetic Programming
Kousuke YOSHIDA, Yuji SAKAMOTO, IEICE technical report. Artificial intelligence and knowledge-based processing, 100, 88, 37, 44, 18 May 2000
In practical application, systems suffer from various noises such as sensor noise and manipulation error. Therefore, it is very important to estimate effects of noise for applying genetic programming. In this paper, we carried out the experiments using a mobile robot due to the estimation. As the results, converged fitness values are decrease with the increase of noise. The values depend on the set of GP function parameters, but GP parameters. Moreover, the experimental results show that the individual are specialized to the noise level in which the individual are evolved., The Institute of Electronics, Information and Communication Engineers, Japanese

座標情報を利用した情報端末上の表示モデルの構築
渡邉学, 山本強, 坂本雄児, 情報処理学会全国大会講演論文集, 60th, 3, 3.63-3.64, 14 Mar. 2000
Japanese

ソートを用いた濃淡画像の可逆符号化
明上山温, 坂本雄児, 山本強, 電子情報通信学会大会講演論文集, 2000, 2, 51, 51, 07 Mar. 2000
一般社団法人電子情報通信学会, Japanese

ソートを用いた濃淡画像の可逆符号化
明上山 温, 坂本 雄児, 山本 強, 電子情報通信学会総合大会講演論文集, 2000, 2, 51, 51, 07 Mar. 2000
一般社団法人電子情報通信学会, Japanese

ソートを用いた高解像度多値画像の可逆符号化
明上山温, 坂本雄児, 山本強, 画像電子学会研究会講演予稿, 176th, 176, 9, 13, 10 Feb. 2000
画像電子学会, Japanese

ソートを用いた高解像度多値画像の可逆符号化
明上山 温, 山本 強, 坂本 雄児, 研究会講演予稿, 176, 9, 13, 10 Feb. 2000
画像電子学会, Japanese

Segmentation of jointed regions using spring model.
TAKAHASHI KOTAKU, KATO MANABU, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 99, 609(EID99 140-152), 73, 78, 04 Feb. 2000
Surgery simulation is one of the most important application field in virtual reality. Because each organ has physical properties such as stiffness, hardness and so on, segmentation of internal organs is indispensable for surgery simulation. But it is difficult to segment regions of organs automatically, because that image has uncertain part. Therefore, we propose a new method that creates spring model from the image, and separate the jointed regions by the force worked at operator designated place. Experiments using artificial images and a medical image, are achieved, whose results show the effectiveness of the proposed method., The Institute of Electronics, Information and Communication Engineers, Japanese

Reflection model using surface roughness control on spatial frequency for computer-generated holograms.
YAMASHITA YUTAKA, NAGAO TOMOHIRO, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 99, 609(EID99 140-152), 67, 72, 04 Feb. 2000
Japanese

Segmentation of jointed regions using spring model
TAKAHASHI Koutaku, KATO Manabu, SAKAMOTO Yuji, ITE Technical Report, 24, 11, 73, 78, 04 Feb. 2000
Surgery simulation is one of the most important application field in virtual reality. Because each organ has physical properties such as stiffness, hardness and so on, segmentation of internal organs is indispensable for surgery simulation. But it is difficult to segment regions of organs automatically, because that image has uncertain part. Therefore, we propose a new method that creates spring model from the image, and separate the jointed regions by the force worked at operator designated place. Experiments using artificial images and a medical image, are achieved, whose results show the..., The Institute of Image Information and Television Engineers, Japanese

Reflection model using surface roughness control on spatial frequency for computer-generated holograms
Yamashita Yutaka, Nagao Tomohiro, Sakamoto Yuji, IEICE technical report. Image engineering, 99, 611, 67, 72, 04 Feb. 2000
To visualize realistic three-dimensional images using computer-generated holograms, reflection model of the surface is very important. This paper proposes a method that controls properties of surface reflection of virtual objects using spatial frequency. It is assumed that the object is constructed by random phase surfaces, which is limited on the spatial frequency. The approach was verified by not only the comouter simulations, but also computer-generated holograms., The Institute of Electronics, Information and Communication Engineers, Japanese

Reflection model using surface roughness control on spatial frequency for computer-generated holograms
Yamashita Yutaka, Nagao Tomohiro, Sakamoto Yuji, IEICE technical report. Electronic information displays, 99, 609, 67, 72, 04 Feb. 2000
To visualize realistic three-dimensional images using computer-generated holograms, reflection model of the surface is very important. This paper proposes a method that controls properties of surface reflection of virtual objects using spatial frequency. It is assumed that the object is constructed by random phase surfaces, which is limited on te spatial frequency. The approach was verified by not only the computer simulations, but also computer-generated holograms., The Institute of Electronics, Information and Communication Engineers, Japanese

Reflection model using surface roughness control on spatial frequency for computer-generated holograms
Yamashita Yutaka, Nagao Tomohiro, Sakamoto Yuji, ITE Technical Report, 24, 11, 67, 72, 04 Feb. 2000
To visualize realistic three-dimensional images using computer-generated holograms, reflection model of the surface is very important. This paper proposes a method that controls properties of surface reflection of virtual objects using spatial frequency. It is assumed that the objects is constructed by random phase surfaces, which is limited on the spatial frequency. The approach was verified by not only the computer simulations, but also computer-generated holograms., The Institute of Image Information and Television Engineers, Japanese

三角パッチを用いた計算機合成ホログラム生成の高速化
長尾智大, 山下裕, 坂本雄児, 電気関係学会北海道支部連合大会講演論文集, 1999, 441, 23 Oct. 1999
Japanese

遺伝的プログラミング(GP)を用いた移動ロボットの制御におけるノイズの影響
吉田浩介, 小林正樹, 坂本雄児, 電気関係学会北海道支部連合大会講演論文集, 1999, 410, 23 Oct. 1999
Japanese

ばねモデルを用いた接合領域の分割法
高橋宏卓, 加藤学, 坂本雄児, 電気関係学会北海道支部連合大会講演論文集, 1999, 439, 23 Oct. 1999
Japanese

手術シミュレーションのための仮想弾性物体の生成と変形
加藤学, 高橋宏卓, 坂本雄児, 電気関係学会北海道支部連合大会講演論文集, 1999, 438, 23 Oct. 1999
Japanese

CGHにおける表面粗さの空間周波数による反射特性制御
山下裕, 坂本雄児, 電気関係学会北海道支部連合大会講演論文集, 1999, 440, 23 Oct. 1999
Japanese

並列処理によるボリュームレンダリングの高速表示アルゴリズム
佐藤英司, 坂本雄児, 電気関係学会北海道支部連合大会講演論文集, 1999, 437, 23 Oct. 1999
Japanese

ノイズ付加環境における遺伝的アルゴリズムを用いた移動ロボットの制御
小林正樹, 吉田浩介, 坂本雄児, 電気関係学会北海道支部連合大会講演論文集, 1999, 409, 23 Oct. 1999
Japanese

画像ブロック内ピクセルのソートとソートテーブルのQuadTree構造を用いた多値画像の可逆符号化
明上山温, 坂本雄児, 山本強, 情報処理学会全国大会講演論文集, 59th, 3, 3.561-3.562, 562, 28 Sep. 1999
Japanese

A Lossless image coding using pixel sort in the image blocks and quadtree for matching the same sort tables
Myojyoyama Atsushi, Sakamoto Yuji, Yamamoto Tsuyoshi, 全国大会講演論文集, 59, 3, "3, 561"-"3-562", 28 Sep. 1999
Information Processing Society of Japan (IPSJ), Japanese

Development of an Avatar Language Chatting System for Satellite Communication.
AOKI YOSHINAO, TANAHASHI SHIN, HASHIMOTO ATSUSHI, SUGIO NAOHISA, SAKAMOTO YUJI, MITSUHASHI RYUICHI, HATSUDA TAKESHI, 電子情報通信学会技術研究報告, 99, 214(SAT99 74-89), 75, 80, 24 Jul. 1999
We propose a chatting system that uses avatar language to communicate across the linguistic barriers. We developed a CG system for generating CG animation of words from avatar language. A communication experiment was performed using a Japanese communications satellite to confirm the validity of the developed chatting system., The Institute of Electronics, Information and Communication Engineers, Japanese

Development of an Avatar Language Chatting System for Satellite Communication
AOKI Yoshinao, TANAHASHI Shin, HASHIMOTO Atsushi, SUGIO Naohisa, SAKAMOTO Yuji, MITSUHASHI Ryuuichi, HATSUDA Takeshi, Technical report of IEICE. SAT, 99, 214, 75, 80, 24 Jul. 1999
We propose a chatting system that uses avatar language to communicate across the linguistic barriers. We developed a CG system for generating CG animation of words from avatar language. A communication experiment was performed using a Japanese communications satellite to confirm the validity of the developed chatting system., The Institute of Electronics, Information and Communication Engineers, Japanese

Development of an Avatar Language Chatting System for Satellite Communication
AOKI Yoshinao, TANAHASHI Shin, HASHIMOTO Atsushi, SUGIO Naohisa, SAKAMOTO Yuji, MITSUHASHI Ryuuichi, HATSUDA Takeshi, Technical report of IEICE. CQ, 99, 216, 75, 80, 24 Jul. 1999
We propose a chatting system that uses avatar language to communicate across the linguistic barriers. We developed a CG system for generating CG animation of words from avatar language. A communication experiment was performed using a Japanese communications satellite to confirm the validity of the developed chatting system., The Institute of Electronics, Information and Communication Engineers, Japanese

表面粗さの空間周波数制御による散乱シミュレーション
山下裕, 坂本雄児, 電子情報通信学会大会講演論文集, 1999, 153, 153, 08 Mar. 1999
The Institute of Electronics, Information and Communication Engineers, Japanese

ノイズ付加箇所による遺伝的アルゴリズムへの影響
小林正樹, 坂本雄児, 電子情報通信学会大会講演論文集, 1999, 20, 180, 180, 08 Mar. 1999
The Institute of Electronics, Information and Communication Engineers, Japanese

The Effect of Noise Additional Position in Genetic Algorithm
KOBAYASHI Masaki, SAKAMOTO Yuji, Proceedings of the IEICE General Conference, 1999, 1, 180, 180, 08 Mar. 1999
The Institute of Electronics, Information and Communication Engineers, Japanese

Scattering simulations using spatial frequency control of surface roughness
YAMASHITA Yutaka, SAKAMOTO Yuji, Proceedings of the IEICE General Conference, 1999, 2, 153, 153, 08 Mar. 1999
The Institute of Electronics, Information and Communication Engineers, Japanese

Generating a mass-spring model from volume data and deformational operators.
KATO MANABU, SAKAMOTO YUJI, 映像情報メディア学会技術報告, 23, 9(IDY99 85-99/HIR99 20-34/MIP99 39-53/AIT99 39-53/NIM99 39-53/VIS99 39-53), 19, 24, 03 Feb. 1999
To realize the surgery simulation using virtual reality, it is necessary to define a deformation and cutting method of the soft objects such as muscle, organ and etc. Therefore, we propose a method modeling the objects by a mass-spring model generated from 3-demensional volume data of X-ray CT, MRI and etc, and define a deformation and cutting by the mass-spring model. In this method, it is possible to generate a mass-spring model from volume data directly by related a voxel and mass point as one to one. Deformation operation is done using a force, move, fix, and cut operators. It is able to represent various actions by combination of these deformational operators., The Institute of Electronics, Information and Communication Engineers, Japanese

Generating a mass-spring model from volume data and deformational operators.
KATO MANABU, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 98, 576(IE98 155-169), 19, 24, 03 Feb. 1999
Japanese

Generating a mass-spring model from volume data and deformational operators
Kato Manabu, Sakamoto Yuji, IEICE technical report. Electronic information displays, 98, 574, 19, 24, 03 Feb. 1999
To realize the surgery simulation using virtual reality, it is necessary to define a deformation and cutting method of the soft objects such as muscle, organ and etc. Therefore, we propose a method modeling the objects by a mass-spring model generated from 3-demensional volume data of X-ray CT, MRI and etc, and define a deformation and cutting by the mass-spring model. In this method, it is possible to generate a mass-spring model from volume data directly by related a voxel and mass point as one to one. Deformation operation is done using a force, move, fix, and cut operators. It is able t..., The Institute of Electronics, Information and Communication Engineers, Japanese

Generating a mass-spring model from volume data and deformational operators
Kato Manabu, Sakamoto Yuji, ITE Technical Report, 23, 9, 19, 24, 03 Feb. 1999
To realize the surgery simulation using virtual reality, it is necessary to define a deformation and cutting method of the soft objects such as muscle, organ and etc. Therefore, we propose a method modeling the objects by a mass-spring model generated from 3-demensional volume data of X-ray CT, MRI and etc, and define a deformation and cutting by the mass-spring model. In this method, it is possible to generate a mass-spring model from volume data directly by related a voxel and mass point as one to one. Deformational operation is done using a force, move, fix, and cut operators. It is able..., The Institute of Image Information and Television Engineers, Japanese

Generating a mass-spring model from volume data and deformational operators
Kato Manabu, Sakamoto Yuji, IEICE technical report. Image engineering, 98, 576, 19, 24, 03 Feb. 1999
To realize the surgery simulation using virtual reality, it is necessary to define a deformation and cutting method of the soft objects such as muscle, organ and etc. Therefore, we propose a method modeling the objects by a mass-spring model generated from 3-demensional volume data of X-ray CT,MRI and etc, and define a deformation and cutting by the mass-spring model. In this method, it is possible to generate a a mass-spring model from volume data directly by related a voxel and mass point as one to one. Deformational operation is done using a force, move, fix, and cut operators. It is abl..., The Institute of Electronics, Information and Communication Engineers, Japanese

A Lossless image coding of 3D image data using Pixel Ordering Tables
Myojyoyama Atsushi, Sakamoto Yuji, Yamamoto Tsuyoshi, 全国大会講演論文集, 57, 2, 89, 90, 05 Oct. 1998
Information Processing Society of Japan (IPSJ), Japanese

A Lossless image coding of 3D image data using Pixel Ordering Tables.
MYOJOYAMA ATSUSHI, SAKAMOTO YUJI, YAMAMOTO TSUYOSHI, 情報処理学会全国大会講演論文集, 57th, 2, 2.89-2.90, Oct. 1998
Japanese

10)ボリュームレンダリングの並列処理アルゴリズム
佐藤 英司, 坂本 雄児, 映像情報メディア学会誌 : 映像情報メディア, 52, 6, 833, 833, 20 Jun. 1998
一般社団法人映像情報メディア学会, Japanese

11)ボクセルオートマタ
土屋 晃一, 坂本 雄児, 映像情報メディア学会誌 : 映像情報メディア, 52, 6, 833, 833, 20 Jun. 1998
一般社団法人映像情報メディア学会, Japanese

Parallel Processing Algorithm of Volume Rendering.
SATO EIJI, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 97, 527(EID97 135-146), 61, 66, 04 Feb. 1998
Japanese

Voxel Automata.
TSUCHIYA KOICHI, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 97, 527(EID97 135-146), 67, 72, 04 Feb. 1998
Japanese

Parallel Processing Algorithm of Volume Rendering
SATO Eiji, SAKAMOTO Yuji, IEICE technical report. Electronic information displays, 97, 527, 61, 66, 04 Feb. 1998
Volume rendering is one method to visualize three-dimensional volume data which are imaged by MRI and X-Ray CT. But because the size of three-dimensional data is large, a lot of time is spent to load data into memory of computer and to rendering calculation. To solve problems mentioned above, a new parallel volume rendering algorithm is proposed. It is possible to distribute three-dimensional data on each parallel processing by the proposed method., The Institute of Electronics, Information and Communication Engineers, Japanese

Voxel Automata
TSUCHIYA Koichi, SAKAMOTO Yuji, IEICE technical report. Electronic information displays, 97, 527, 67, 72, 04 Feb. 1998
In methods which deform 3-dimensional data, limited prediction methods, a simulation method that uses the spring model, a method that cuts away objects using masking, etc. are included. We propose a method based on Voxelautomata which based on voxel & cellular automatons with the objective of deforming an object composed of density values using a small number process. The proposed method can directly deform the object by avoiding use of approximation mesh and making mask. The proposed method 3-dimensional data and by determining 5 mapping functions performs the deformation of the object. On..., The Institute of Electronics, Information and Communication Engineers, Japanese

Parallel Processing Algorithm of Volume Rendering
SATO Eiji, SAKAMOTO Yuji, ITE Technical Report, 22, 9, 61, 66, 04 Feb. 1998
Volume rendering is one method to visualize three-dimensional volume data which are imaged by MRI and X-Ray CT. But because the size of three-dimensional data is large, a lot of time is spent to load data into memory of computer and to rendering calculation. To solve problems mentioned above, a new parallel volume rendering algorithm is proposed. It is possible to distribute three-dimensional data on each parallel processing by the proposed method., The Institute of Image Information and Television Engineers, Japanese

Voxel Automata
TSUCHIYA Koichi, SAKAMOTO Yuji, ITE Technical Report, 22, 9, 67, 72, 04 Feb. 1998
In methods which deform 3-dimensional data, limited prediction methods, a simulation method that uses the spring model, a method that cuts away objects using masking, etc. are included. We propose a method based on Voxelautomata which based on voxel & cellular automatons with the objective of deforming an object composed of density values using a small number process. The proposed method can directly deform the object by avoiding use of approximation mesh and making mask. The proposed method uses 3-dimensional data and by determining 5 mapping functions performs the deformation of the objec..., The Institute of Image Information and Television Engineers, Japanese

Parallel Processing Algorithm of Volume Rendering
SATO Eiji, SAKAMOTO Yuji, IEICE technical report. Image engineering, 97, 529, 61, 66, 04 Feb. 1998
Volume rendering is one method to visualize three-dimensional volume data which are imaged by MRI and X-Ray CT. But because the size of three-dimensional data is large, a lot of time is spent to load data into memory of computer and to rendering calculation. To solve problems mentioned above, a new parallel volume rendering algorithm is proposed. It is possible to distribute three-dimensional data on each parallel processing by the proposed method., The Institute of Electronics, Information and Communication Engineers, Japanese

Voxel Automata
TSUCHIYA Koichi, SAKAMOTO Yuji, IEICE technical report. Image engineering, 97, 529, 67, 72, 04 Feb. 1998
In methods which deform 3-dimensional data, limited prediction methods, a simulation method that uses the spring model, a method that cuts away objects using masking, etc.are included.We propose a method based on Voxelautomata which based on voxel & cellular automatons with the objective of deforming an object composed of density values using a small number process. The proposed method can directly deform the object by avoiding use of approximation mesh and making mask.The proposed method uses 3-dimensional data and by determining 5 mapping functions performs the deformation of the object.O..., The Institute of Electronics, Information and Communication Engineers, Japanese

Effect of noise in controlling mobile robot using genetic algorithm.
KOBAYASHI MASAKI, SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1998, 175, 1998
Japanese

Generation of virtual elastic bodies from images and a deformation operator.
KATO MANABU, SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1998, 431, 1998
Japanese

Simulation of light scatter with surface roughness taken into consideration.
YAMASHITA YUTAKA, SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1998, 433, 1998
Japanese

Deformation of Volume data by Cellular Automaton.
TSUCHIYA KOICHI, SAKAMOTO YUJI, 電子情報通信学会大会講演論文集, 1997, 157, Sep. 1997
Japanese

Lossless coding of image data using memory tables of pixel location in fixed blocks.
MYOJOYAMA ATSUSHI, SAKAMOTO YUJI, 電子情報通信学会大会講演論文集, 1997, 114, Sep. 1997
Japanese

Parallel processing using divided 3D images for volume rendering.
SAKAMOTO YUJI, SATO EIJI, ZANA M, 電子情報通信学会大会講演論文集, 1997, 152, Sep. 1997
Japanese

A cross-sectional image generation method which uses compressed data in its compressed form.
ZANA M, SAKAMOTO YUJI, 電子情報通信学会大会講演論文集, 1997, 182, Sep. 1997
Japanese

Deformation of Volume data by Cellular Automaton
Tsuchiya Kouichi, Sakamoto Yuji, Proceedings of the Society Conference of IEICE, 1997, 0, 157, 157, 13 Aug. 1997
物体のボリュームデータ (3次元データ) を仮想現実を用いた加工, 変形技術は, 手術シミュレーションや自由曲面の設計など多くの分野への応用が期待されている. 本稿では, セルラオートマトンを用いたボリュームデータの変形法を提案する., The Institute of Electronics, Information and Communication Engineers, Japanese

Lossless coding of image data using memory tables of pixel location in fixed blocks
Myojyoyama Atusi, Sakamoto Yuji, Proceedings of the Society Conference of IEICE, 1997, 0, 114, 114, 13 Aug. 1997
さまざまな分野でデジタル画像が用いられているが、その中でも医療画像(CT, MRI画像)など信頼性が求められる画像データの圧縮に対しては、多くの場合可逆画像圧縮が用いられる。 予測符号化効率は画像ピクセルの相関の大きさに左右されるため、画像によって予測符号化効率の差が著しい場合が多々ある。このような画像による予測符号化効率の差を小さくし、かつ符号化効率を上げることは、処理時における画像データ保存スペースの最適な確保という面においても圧縮自体においても有用である。 本稿では予測符号効率を向上させることを目的として、画像データを固定したブロックに分割し、有限個のピクセル位置記憶テーブルを用いた方法を提案する。, The Institute of Electronics, Information and Communication Engineers, Japanese

Parallel processing using divided 3D images for volume rendering
SAKAMOTO Yuji, SATO Eiji, ZANA Musiyiwa, Proceedings of the Society Conference of IEICE, 1997, 0, 152, 152, 13 Aug. 1997
ボリュームレンダリングはCT(Computed Tomography)やMRI(Magnet Resonance Imaging)で得られた3次元画像を表示する方法として有効な方法である. しかし, 計算に多くの時間がかかることが, 医療などの現場での利用に大きな障害となっている. 複数の計算機による並列処理は, 高速化手法として期待されているが, 3次元の膨大なデータをどのように扱うかが問題であった. 本稿では, 3次元画像を各計算機で分割して持つことができるボリュームレンダリングの並列処理手法を提案する., The Institute of Electronics, Information and Communication Engineers, Japanese

A cross-sectional image generation method which uses compressed data in its compressed form
Zana Musiyiwa, Sakamoto Yuji, Proceedings of the Society Conference of IEICE, 1997, 0, 182, 182, 13 Aug. 1997
我々はX線CT (X-ray Computed Tomography), MRI(Magnetic Resonance Imaging)などにより、得られた3次元画像より断面画像を生成する研究を行ってきた. 従来法で断面画像を生成する際に3次元データが膨大なため読み込み時間が多くかかることとRAMとHDDメモリ量が多く必要であるなどの問題点があった. 本研究ではHDDでのファイルサイズと読み込む時間を減らすためにMRIデータをoctree圧縮し、少ないRAM容量で断面画像生成するためにoctreeによって圧縮されたままの状態のデータより断面画像を生成する方法の提案する., The Institute of Electronics, Information and Communication Engineers, Japanese

A Study of the Effect of Noise on Takeover Time.
SAKAMOTO YUJI, GOLDBERG D, 電子情報通信学会技術研究報告, 97, 63(AI97 1-11), 47, 54, 22 May 1997
This paper discusses the effect of noise on takeover time for a genetic algorithm. We propose models of tournament selection in a noisy environment. The models are shown to predict the proportion of the individuals accurately. The models lead to the derivation of a simplified arpproximate equation for takeover time, and confirm the validity of the approximation for experiments., The Institute of Electronics, Information and Communication Engineers, Japanese

Improvement of reversible encoding efficiency by the change of block size of the pixel position memory table.
AKEGAMIYAMA ATSUSHI, SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1997, 315, 1997
Japanese

Volume rendering by memory distributed parallel processing.
SATO EIJI, SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1997, 357, 1997
Japanese

Deformation of volume data using Cellular Automaton.
TSUCHIYA KOICHI, SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1996, 8, 1996
Japanese

Reversible coding method for X-ray CT image by operation of encoding order table of finite number.
MYOJOYAMA ATSUSHI, SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1996, 372, 1996
Japanese

Parallel processing of medical cross-sectional images using agents.
ZANA M, SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1996, 32, 1996
Japanese

An Automatic Extraction Method for Internal Part of Organs from MRI featuring variable Sized of Texture Region.
KAWAHARA TOSHIKAZU, SAKAMOTO YUJI, 電子情報通信学会技術研究報告, 95, 131(MBE95 32-45), 101, 106, 24 Jun. 1995
Classification and Segmentation are important image processing methods as preprocessing means for distinguishing and recognition. These two methods are especially basic processes for automatic extraction of internal organs from 3D data obtained by MRI and CT. But an automatic precise extraction method which uses MRI to display soft tissue with high contrast has not been development. In this paper, we prppose a method which extracts the internal organs from MRI data by combining the result obtained from varying sizes of texture region to classify the internal organs. In this method, initially we use a large texture region to roughly extract the internal organ, then we make the texture region smaller to add detail and edges to the roughly extracted data. The aim of this method is to produce high quality result., The Institute of Electronics, Information and Communication Engineers, Japanese

Characteristic of Indoor Radio Propagation.
SAKAMOTO YUJI, TAMURA AKIYOSHI, HATA YOSHIYUKI, 電子情報通信学会技術研究報告, 95, 97(CS95 56-66), 17, 22, 20 Jun. 1995
Recently, there has been indoor radio communication systems such as radio LAN systems and personal communication services systems which are based on micro-cellular method. To characterized indoor radio propagation is very important for successful design of these systems. However, study of the characterization is not enough to implement these design. The channel of the indoor environment is nonstationary in time, even when the transmitter and receiver are fixed. We show the results of the measurement of the temporal characteristic and discuss the statistics of the data., The Institute of Electronics, Information and Communication Engineers, Japanese

An Extraction Method of Brain Tissue from MR Images Considering Model Feature Region Size
Kawahara Toshikazu, Sakamoto Yuji, Proceedings of the IEICE General Conference, 1995, 1, 205, 205, 27 Mar. 1995
近年、CT(Computer Tomography)画像やMRI(Magnetic Resonance Image)等の医療画像の進歩により人体内部の表示が可能となった。しかし、これらの画像は2次元で表示され、臓器内部を3次元に再構成するには、計算機により臓器のみを抽出することが望まれる。この抽出を行う方法に、特徴量を用いた処理がある。この特徴量は領域を大きくして求めると、抽出、非抽出領域において相関が弱いため分類が比較的、容易に行うことができるが、実際よりも、その結果が小さく抽出される。一方、領域を小さくすると、輪郭をより精度よく分類することができるが、抽出、非抽出領域において相関が強い部分が多数現われるため、誤った分類を行い易い。そこで、本実験では領域の大きさを段階的に小さくしていき、各結果を相補的に結合して目的とする領域を抽出するものである。, The Institute of Electronics, Information and Communication Engineers, Japanese

Selection of Features for Classification Method Using Neural Network
Sakamoto Yuji, Proceedings of the IEICE General Conference, 1995, 2, 217, 217, 27 Mar. 1995
領域の分類は、画像処理では重要な処理法であるが、特徴量の選択、評価関数のパラメータの決定は発見的に求められ、手間のかかる作業であった。この問題の解決のために、学習型のニューラルネットワーク(ANN)を用いた教師付分類法を研究してきた。本稿では、この方法において特徴量の分類への寄与率を考え、特徴量の選択法を提案するとともに、MRI(Magnetic Resonance Imaging)に適応した結果を報告する。, The Institute of Electronics, Information and Communication Engineers, Japanese

3D Voxel Data Division Method suitable for the Parallel Processing of Cross-sectional Images
Zana Musiyiwa, Sakamoto Yuji, 全国大会講演論文集, 50, 2, 327, 328, 15 Mar. 1995
医用で用いられているMRI,CTなどの3次元画像は数MBの大きなものとなり、この大量のデータのアクセスが処理速度を制限する要因となる(1)。本研究の目的はLANによって接続された複数の計算機を用いて断面画像生成の並列処理速度を上げることである。特にデータ量が大きいため3Dボクセルの分割法が重要である。今断面生成に用いられている投影手法は画素投影法(2)と画素探索法(3)がある。この方法を用いて物体の診断に必要な断面画像を簡単に選択することができる(4),(5)。本論文ではある断面にたいして必要な3次元データを分割するアルゴリズムを提案する。, Information Processing Society of Japan (IPSJ), Japanese

3D Voxel Data Division Method suitable for the Parallel Processing of Cross-sectional Images.
SAKAMOTO YUJI, ZANA M, 情報処理学会全国大会講演論文集, 50th, 2, 2.327-2.328, Mar. 1995
Japanese

An Extraction Method of Brain Tissue from MR Images Considering Modal Feature Region Size.
KAWAHARA TOSHIKAZU, SAKAMOTO YUJI, 電子情報通信学会大会講演論文集, 1995, Sogo Pt 6, 205, Mar. 1995
Japanese

Selection of Features for Classification Method Using Neural Network.
SAKAMOTO YUJI, 電子情報通信学会大会講演論文集, 1995, Sogo Pt 7, 217, Mar. 1995
Japanese

A Parallel Processing Method for Volume Rendering.
ZANA M, SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1995, 450, 1995
Japanese

Automatic organ extraction method making the size of texture region from MRI variable. Examination on coupling rule retaining unclear information.
KAWARA TOSHIKAZU, SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1995, 362, 1995
Japanese

A Model of Temporal Variations of Radio Propagation in Rooms.
SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1995, 248, 1995
Japanese

MRI画像を領域分割するための特徴量の検討
川原敏一, 坂本雄児, 電気関係学会北海道支部連合大会講演論文集, 1994, 370, 1994
Japanese

Measurement of egg BCG using electromagnetic induction coil.
ONO HIROSHI, SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1994, 292, 1994
Japanese

Parallel Processing of the Projection of a 2-Dimensional Cross-sectional Image from 3-Dimensional Data.
ZANA M, SAKAMOTO YUJI, 電気関係学会北海道支部連合大会講演論文集, 1994, 346, 1994
Japanese

Image Segmentation by Maximum-Homogeneity Based Region growing Method.
ZHANG S, SAKAMOTO YUJI, KAWASHIMA TOSHIO, 電気関係学会北海道支部連合大会講演論文集, 1994, 282, 1994
Japanese

Mesurement of Indoor Propagation Characteristic Due to Human Movement.
SAKAMOTO YUJI, HATA YOSHIYUKI, 電気関係学会北海道支部連合大会講演論文集, 1994, 312, 1994
Japanese

A Classfication of 3D Images by 2D Histgram Using Gradients.
坂本雄児, 大塚晃央, 青木由直, 電子情報通信学会大会講演論文集, 1993, Shunki Pt 7, 7.231, Mar. 1993
Japanese

3D Region-Growing Method Using Boundry Condition by Solid Models.
ITADA YOSHIKATSU, SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会技術研究報告, 92, 475(MBE92 102-111), 25, 32, 23 Feb. 1993
Japanese

Propagation of Time Characteristics in Building.
坂本雄児, 畑善之, 電気関係学会北海道支部連合大会講演論文集, 1993, 248, 1993
Japanese

Segmentation Method for MRI Using Supervised Learning.
坂本雄児, 電気関係学会北海道支部連合大会講演論文集, 1993, 270, 1993
Japanese

Differential Volume Rendering Method using a Rate of Contribution.
板田吉勝, 坂本雄児, 青木由直, 電子情報通信学会大会講演論文集, 1992, Shuki Pt 6, 6.254, Sep. 1992
Japanese

A Method to Compute Complex Amplitude Distribution on Hologram from Plane Surface.
五十嵐政志, 坂本雄児, 青木由直, 電子情報通信学会大会講演論文集, 1992, Shuki Pt 6, 6.229, Sep. 1992
Japanese

A Study of Making Animation in Intelligent Communication for Images of Sign Language.
棚橋真, 坂本雄児, 川嶋稔夫, 山本克之, 青木由直, 電子情報通信学会大会講演論文集, 1992, Shuki Pt 1, 1.154, Sep. 1992
Japanese

Interactive image restoration for satellite remote sensing images.
LIU H, MITSUHASHI RYUICHI, SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会技術研究報告, 92, 202(SANE92 22-34), 53, 58, 28 Aug. 1992
Japanese

A study of relief of delay in intelligent communication for images by satellite.
TANAHASHI SHIN, SAKAMOTO YUJI, KAWASHIMA TOSHIO, YAMAMOTO KATSUYUKI, AOKI YOSHINAO, 電子情報通信学会技術研究報告, 92, 202(SANE92 22-34), 73, 76, 28 Aug. 1992
Japanese

Reconstruction method of front looking radar using a few antennas.
SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会技術研究報告, 92, 202(SANE92 22-34), 11, 16, 28 Aug. 1992
Japanese

A study on system construction of snow search radar.
MITSUHASHI RYUICHI, TANAHASHI SHIN, SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会技術研究報告, 92, 202(SANE92 22-34), 17, 22, 28 Aug. 1992
Japanese

2)通信衛星による手話画像の知的伝送システムの開発(〔情報ディスプレイ研究会 無線・光伝送研究会 画像通信システム研究会 画像応用研究会〕合同)
徐 軍, 棚橋 真, 坂本 雄児, 青木 由真, テレビジョン学会誌, 46, 6, 788, 788, 20 Jun. 1992
一般社団法人映像情報メディア学会, Japanese

Development of a Transmitting System using a Satellite for Intelligent Communication of Sign Language.
XU J, 棚橋真, 坂本雄児, 青木由直, 電子情報通信学会大会講演論文集, 1992, Shunki Pt 1, 1.293, 12, Mar. 1992
We have developed a transmitting system using a satellite for intelligent communication of sign language images. This paper describes the configuration of the system, and the description of the arm's motion in sign language dictionary for image synthesis., The Institute of Image Information and Television Engineers, Japanese

A Study of a Radar System for car.
坂本雄児, 青木由直, 電子情報通信学会大会講演論文集, 1992, Shunki Pt 2, 2.583, Mar. 1992
Japanese

A Method To Make Computer Generated Holograms Of 3-D Objects.
五十嵐政志, 坂本雄児, 青木由直, 電子情報通信学会大会講演論文集, 1992, Shunki Pt 7, 7.205, Mar. 1992
Japanese

Transparent Projection Method for Recognition of 3-D Internal structure.
板田吉勝, 坂本雄児, 青木由直, 電子情報通信学会大会講演論文集, 1992, Shunki Pt 7, 7.165, Mar. 1992
Japanese

A Study of Delay in Intelligent Communication for Images by Satellite.
棚橋真, 坂本雄児, 川嶋稔夫, 山本克之, 青木由直, 電子情報通信学会大会講演論文集, 1992, Shunki Pt 1, 1.294, Mar. 1992
Japanese

A two-dimentional histogram by pixel value and the size of normal vector for clustering CT images.
OTSUKA AKIO, SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会技術研究報告, 91, 477(IE91 113-116), 17, 24, 21 Feb. 1992
Japanese

Development of a Transmitting System using a Satellite for Intelligent Communication of Sign Language
XU Jun, TANAHASHI Shin, SAKAMOTO Yuji, AOKI Yoshinao, ITEJ Technical Report, 16, 10, 7, 12, 30 Jan. 1992
We have developed a transmitting system using a satellite for intelligent communication of sign language images. This paper describes the configuration of the system, and the description of the arm's motion in sign language dictionary for image synthesis., The Institute of Image Information and Television Engineers, Japanese

Control of an Overhead Travelling Crane System Based on the Model Reference Adaptive Control System with a Fuzzy Adaptation Rule
SONG Beidong, SAKAMOTO Yuji, HASIMOTO Yukio, AOKI Yoshinao, Journal of Japan Society for Fuzzy Theory and Systems, 3, 4, 177, 185, 15 Nov. 1991
モデル規範形適応制御系(Model Reference Adaptive Control System, MRACS)は、追従過程のオーバシュート、上昇時間、などの制御性能指標を定量的に指定することが要求されるようなサーボ系の設計に対し有効である。しかし、モデル規範適応制御系における適応則の設計においてプラントの線形モデルが必要であるので、プラントが複雑な非線形であるような場合、モデル規範形適応制御系を適用することが困難となる。この問題を解決するために、モデル規範形適応制御系の適応則の設計にファジィ推論を導入し、ファジィ適応則をもつモデル規範形適応制御系を提案した。また、それを天井クレーンの振れ止め・位置制御に応用し、天井クレーン制御におけるトロリーが終着位置に達する時間や位置のオーバシュートの制御性能指標を定量的に指定することができることを示した。エネルギに注目した制御方式を用いることによって、制御系の漸近安定性が厳密に保証することができる。さらに天井クレーン制御の模型実験結果により、ファジィ適応則をもつモデル規範形適応制御系と天井クレーン制御への応用の有効性を示した。, Japan Society for Fuzzy Theory and intelligent informatics, Japanese

A Method of Image Reconstruction for Snow Search Radar Considering the Propagation of Multi-Frequency Microwave Holograms in Snow.
MITSUHASHI RYUICHI, SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会技術研究報告, 91, 213(AP91 61-73), 87, 92, 19 Sep. 1991
Japanese

A Method of Image Reconstruction for Snow Search Radar Considering the Effect of Boundary and Permittivity of Accumulated Snow.
MIHASHI RYUICHI, SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会大会講演論文集, 1991, Shuki Pt 2, 2.411, Sep. 1991
Japanese

Overhead Travelling Cranes Control by Fuzzy Reasoning.
SONG B, SAKAMOTO YUJI, AOKI YOSHINAO, HASHIMOTO YUKIO, 電子情報通信学会大会講演論文集, 1991, Shuki Pt 1, 1.136, Sep. 1991
Japanese

Reconstruction Method of Long-wave Holography Using Learning Algorithm.
SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会大会講演論文集, 1991, Shuki Pt 2, 2.92, Sep. 1991
Japanese

System Design of Indoor Radio Network.
SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会技術研究報告, 91, 62(OCS91 1-8), 25, 30, 23 May 1991
Japanese

Long wave-length holography using back propagation.
SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会全国大会講演論文集, 1991, Spring Pt 7, 7.208, Mar. 1991
Japanese

構内無線ネットワークの構成法に関する考察
坂本雄児, 信学技報, CS91, 5, 1991

Office cordless telephone system. Hitachi cordless office system.
FURUYA TSUNEO, HASEGAWA YOSHIRO, ASAKAWA HISAYUKI, SAKAMOTO YUJI, NAKAMURA TOMOYASU, 日立評論, 72, 9, 877, 884, Sep. 1990
日立評論社, Japanese

Research on regional extraction of three-dimensional image data.
KIKUCHI TAKAFUMI, SAKAMOTO YUJI, AOKI YOSHINAO, 北海道大学工学部研究報告, 141, 137, 153, Jul. 1988
北海道大学 = Hokkaido University, Japanese

Display Method and Display Device of Three-Dimensional Data
TAKAHASHI Yoshinari, SAKAMOTO Yuji, AOKI Yoshinao, NITADORI Kazuhiko, ITE Technical Report, 42, 5, 33, 38, 20 May 1988
The Institute of Image Information and Television Engineers, Japanese

7)雪中レーダシステムにおける3次元画像処理装置(〔画像通信システム研究会画像処理・画像応用研究会〕合同)
横路 浩明, 菊池 隆文, 坂本 雄児, 青木 由直, テレビジョン学会誌, 42, 5, 510, 511, 20 May 1988
一般社団法人映像情報メディア学会, Japanese

An idea of quasi-real time system for snow search radar.
YOKOMICHI HIROAKI, SAKAMOTO YUJI, AOKI YOSHINAO, 電子情報通信学会全国大会講演論文集, 1988, Pt. C-1, 1.442, Mar. 1988
Japanese

Three-dimensional imaging system of snow search radar.
YOKOMICHI HIROAKI, KIKUCHI TAKAFUMI, SAKAMOTO YUJI, AOKI YOSHINAO, テレビジョン学会技術報告, 12, 9, 39, 44, Feb. 1988
The Institute of Image Information and Television Engineers, Japanese

Display method and display device of three-dimensional data.
TAKAHASHI YOSHINARI, SAKAMOTO YUJI, AOKI YOSHINAO, NITADORI KAZUHIKO, テレビジョン学会技術報告, 12, 9, 33, 38, Feb. 1988
The Institute of Image Information and Television Engineers, Japanese

Display Method and Display Device of Three-Dimensional Data
TAKAHASHI Yoshinari, SAKAMOTO Yuji, AOKI Yoshinao, NITADORI Kazuhiko, ITEJ Technical Report, 12, 9, 33, 38, Feb. 1988
The Institute of Image Information and Television Engineers, Japanese

Three-dimensional imaging system of Snow Search Radar
YOKOMICHI Hiroshi, KIKUCHI Takafumi, SAKAMOTO Yuji, AOKI Yoshinao, ITEJ Technical Report, 12, 9, 39, 44, Feb. 1988
The Institute of Image Information and Television Engineers, Japanese

A method of displaying three-dimensional image data in under-snow radar by radio-wave holography.
AOKI YOSHINAO, TAKAHASHI YOSHINARI, SAKAMOTO YUJI, 電子情報通信学会半導体・材料部門全国大会講演論文集, 1987, 2, 2.297-2.298, Nov. 1987
Japanese

Considerations of display algorithm for three dimensional digital data.
TAKAHASHI YOSHINARI, SAKAMOTO YUJI, AOKI YOSHINAO, 情報処理学会全国大会講演論文集, 35th, 3, 1997, 1998, 1987
Japanese

Extension of FIR filter to three dimension and its evaluation.
KIKUCHI TAKAFUMI, SAKAMOTO YUJI, AOKI YOSHINAO, 情報処理学会全国大会講演論文集, 35th, 3, 2001, 2002, 1987
Japanese

Experimental results of 3D objects using under snow radar.
SAKAMOTO YUJI, TAKAHASHI YOSHINARI, AOKI YOSHINAO, MITSUHASHI RYUICHI, 寒地技術シンポジウム講演論文集, 1987, 168, 172, 1987
Japanese

An improved method for the multi-frequency holography reconstruction.
TAJIRI KATSUHIRO, SAKAMOTO YUJI, AOKI YOSHINAO, 電子通信学会技術研究報告, 86, 181, 23-28(A.P86-92), 09 Oct. 1986
Japanese

Detection of three dimensional shape of objects buried in snow.
SAKAMOTO YUJI, TAJIRI KATSUHIRO, AOKI YOSHINAO, 電子通信学会技術研究報告, 86, 181, 9-14(A.P86-90), 09 Oct. 1986
Japanese

マイクロコンピューター用液晶ディスプレイを用いた計算機ホログラフィ
石川貴之, 坂本雄児, 青木由直, 情報処理学会研究報告計算機アーキテクチャ（ARC）, 1986, 20, 1, 8, 17 Mar. 1986
Japanese

Computer holography using liquid crystal display for micro-computers.
ISHIKAWA TAKAYUKI, SAKAMOTO YUJI, AOKI YOSHINAO, 情報処理学会研究報告, 86, 20(MC-39), 39.4.1-39.4.8, 17 Mar. 1986
Japanese

Three dimensional reconstruction of micro-wave holograpy.
SAKAMOTO YUJI, TAJIRI KATUHIRO, AOKI YOSHINAO, 電子通信学会技術研究報告, 85, 100, 55-62(MW85-52), 26 Jul. 1985
Japanese

12)3次元情報の簡易表示装置の試作(画像通信システム研究会(第72回))
佐々木 敏夫, 坂本 雄児, 思田 邦夫, 青木 由直, テレビジョン学会誌, 39, 7, 655, 655, 20 Jul. 1985
一般社団法人映像情報メディア学会, Japanese

An experimental construction of a simple displaying system for three dimentional information.
SASAKI TOSHIO, SAKAMOTO YUUJI, ONDA KUNIO, AOKI YOSHINAO, 電子通信学会技術研究報告, 84, 308, 67, 70, 28 Feb. 1985
The Institute of Image Information and Television Engineers, Japanese

Remote-sensing in fallen snow using multfrequency micro-wave holography.
SAKAMOTO YUJI, TAKAHASHI YUKINOBU, IIJIMA YOSHIHIRO, AOKI YOSHINAO, 電子通信学会技術研究報告, 84, 51, 57-64(AP84-21), Jun. 1984
Japanese, Summary national conference

積雪中のマイクロ波リモートセンシングシステムの試作
高橋幸伸, 坂本雄児, 青木由直, 電子通信学会技術研究報告, 83, 70, 43-48(MW83-22), 24 Jun. 1983
Japanese

デバイス不要な没入型ホロリアリティ空間の構築
科学研究費助成事業
01 Apr. 2022 - 31 Mar. 2025
坂本 雄児
日本学術振興会, 基盤研究(B), 北海道大学, 22H03621

Study on 3D stress-free HMD using electronic holography
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
Apr. 2016 - Mar. 2020
Sakamoto Yuji
We succeeded in developing head-mounted displays (holo-HMDs) with the world's smallest and lightest electronic holography technology. In addition, we have proposed a method that enables real-time calculation and communication at the current level of hardware technology though researches of high-speed calculation methods and data compression methods. These researches indicate that the holo-HMD can be realized as a system. On the other hand, the deterioration of image quality due to speckles is a remained problem, but we have proposed the suppression method using an algorithm and showed the possibility of suppression. It is necessary to continue to study the measurement of physiological responses.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 16H02852

Evaluationof Binocular and Multi-view 3D image with Biogical Response
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
Apr. 2014 - Mar. 2017
OKUYAMA FUMIO, Sakmoto Yuji
The characteristics of binocular and multi-view 3D images are primarily in the sense of depth perception due to parallax,so we evaluated the sense of depth from the objective biological response. Therefore, the purpose is to evaluate the depth perception by measuring the horizontal vergence eye movement of the human eye. We were able to measure horizontal vergence eye movement during 3D image viewing, using the system measuring the pupil TV image processing with accuracy of 0.2 degrees. We found saccade and pursuit eye movements frequently with large magnitude during general natural 3D image viewing , but we found a
small vergence without sudden fluctuations. It is suggested that presented parallax amount and distribution in 3D video image have a large influence on depth perception, but elucidation of the relation between parallax and vergence is a future task.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Suzuka University of Medical Science, 26420399

Evaluation of 3D light field reconstruction in terms of visual function using 3D Holo-TV
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
Apr. 2011 - Mar. 2015
SAKAMOTO Yuji, OKUYAMA Fumio, MIYANAGA Yoshikazu, MIYAO Masaru
A three-dimensional holographic television (3D Holo-TV) based on holography technique is seen as an ultimate 3D TV system. To evaluate the light space field generated by a 3D Holo-TV system in terms of the visual performance, we developed the special designed a 3D Holo-TV system that is able to measure the responses of accommodations and vergence. In the experiments, the responses are measured when observers watched the motionless and moving targets displayed by the 3D Holo-TV. The experimental results strongly indicate that 3D Holo-TV is a superior 3D display because there is no difference between the responses by the real object and ones by the 3D Holo-TV.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23300032

Study on optical evaluation methods for three-dimensional images by using an optical-wave reconstruction simulator
Grants-in-Aid for Scientific Research
2010 - 2011
SAKAMOTO Yuji
A software for analyzing optical characteristics of various three-dimensional displays and an optical-wave reconstruction simulator using by an electro-holography that can simulate the three-dimensional images of various types of three-dimensional displays were developed. The basic relations between optical characteristics and subjective evaluations were clarified by using them
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, Principal investigator, Competitive research funding, 22650015

波面記述法による実空間記録
科学研究費補助金(萌芽研究)
2007 - 2008
坂本 雄児
1. 目的多視点画像の撮影システムや、3Dディスプレイなど、3次元画像の様々な収集、表示システム間の3次元データを正規化する方法の一つである波面記述法において, 以下の点を明らかにする. (1)データ間の変換法のより深い理解 : 特に、多視点画像より波面記述データへの変換, (2)実空間への応用 : 実写多視点画像より波面記述データへの変換法の検討2. 平成19年度の研究実績開発した多視点画像撮影システムにより撮影された3次元画像より任意視点画像およびホログラムによる3次元像の表示を行い、変換法が有効であることを示した。3. 平成20年度の研究実績(1)多くの視点での撮影が必要とされていた従来のアルゴリズムを発展させ、撮影点数が少なく, かつ高分解能な立体画像の波面記述データに変換する新アルゴリズムを開発。(2)撮影位置に自由度が無かったものを, 比較的自由な位置からの撮影が可能な新アルゴリズムを開発。(3)上記, (1)(2)のアルゴリズムについてホログラムによる立体表示により有効性を確認。4. 今後の課題(1)連続的な視差と奥行き情報の内在が理論的にどう解釈されるべきか。(2)提案したアルゴリズムの特性や適応限界等の理論的, 実験的検討が必要。
文部科学省, 萌芽研究, 北海道大学, Principal investigator, Competitive research funding, 19650013

波面記述法による3次元空間のモデリング
科学研究費補助金(萌芽研究)
2004 - 2005
坂本 雄児, 今井 英幸
1,研究概要3次元映像をデジタルデータとして記録する方法として,波面を記録する波面記述法の基礎理論を確立する。この方法は,従来法に比べ格段の情報量削減の可能性があるが,実際的なアルゴリズムやその座標変換等の基礎理論において明らかになっていない点が多くあり,これを研究する。2.平成17年度の研究状況(1)波面記述法の有効性を検証する目的で,平成16年度に引続きホログラフィックディスプレイ装置を開発した。これを用いて,波面記述法からホログラムデータへの変換および光学再生実験を行い,立体像の表示に成功した。この実験を通して波面記述法とホログラフィックディスプレイの親和性の高さを確認した。(2)多眼画像データなどの3次元画像入力装置で得られたデータの波面記録法への変換方法の検討を行い,変換アルゴリズムを明らかにした。さらに、上記(1)のシステムにより、立体像表示実験を行い、その有効性を明らかにした。(3)この研究過程で,平成16年度に円筒形の記録面を用いた記録法が波面記述法に適していることが明らかになったが,本年度は,円筒形記録面での高速変換アルゴリズムの検討を行い,実用化の可能性のある非常に高速なアルゴリズムを明らかにした。
文部科学省, 萌芽研究, 北海道大学, Principal investigator, Competitive research funding, 16650014

Study on 3D displaying for volume data using holographic 3D display
Grants-in-Aid for Scientific Research(基盤研究(B))
2003 - 2005
Yuji SAKAMOTO, 明上山 温, 木村 浩一, 松島 恭治
1.ObjectivesPurpose of this study is to develop holographic 3D display system for volume data using a computer-generated hologram technique and to evaluate the 3D images.2.Results of research(1)We succeeded in displaying a three-dimensional image by a hologram of volume data and were able to realize a large-sized hologram in comparison with before. New knowledge was provided through this development technically. In addition, I clarified the effectiveness of the method by the large-size holograms that are able to see by naked eyes. However, on the other hand, the problems such as quantizatio...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 北海道大学, Principal investigator, Competitive research funding, 15300025

Basic Research on the Development of the Avatar Language Communication Technique Across the Linguistic Barrier of Different Language and Discussion on the International Standardization
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
2001 - 2003
AOKI Yoshinao, HASAYAMA Miki, ARAKI Kenji, YAMAMOTO Tsuyoshi, YAMAGATA Sekiji, AOKI Naofumi, SAKAMOTO Yuji, KANG Seok
The research results are listed as follows ;
(1) We discussed an 'avatar language communication' in relation to communication across the linguistic barrier, where we developed a non-verbal communication with gestures and emotional expressions of avatars displayed using CG (computer graphics) animations.
(2) We developed an avatar language chatting system supposing an international communication using avatar language between Japan and Korea and an experimental discussion was done, resulting in the possibility of an avatar chatting system across the linguistic barrier.
(3) We developed an avatar communication system using smiley marks (Kao-moji in Japanese), where emotional expression is input by symbols on the keyboard and the developed face-creation editor produces emotional expression of the comic face. The advantage of the comic expression of face is shown by an experiment of communication with emotion, where a new concept of CAU (Comic Action Unit) is proposed to create comic CG faces.
(4) We proposed the technique to communicated in the circumstances of ubiquitous computer and communication with a special interface system to input gesture of communicator developed in this research.
(5) A discussion on the application of avatar language to the WBT (Web Based Training) in order to apply the avatar language communication to the e-learning.
(6) As an application of avatar language communication system, a service on the mobile phone is proposed and the potentiality of this application is demonstrated by constructing a mobile phone system in a PC.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 13305026

リアリスティック計算機合成ホログラムの物体光計算アルゴリズムの基礎研究
科学研究費補助金(萌芽的研究, 萌芽研究)
2001 - 2002
坂本 雄児
申請した研究では計算機合成ホログラムにおいて,リアリスティックな立体像の合成に欠かせない、レンダリング技法の研究・検討を行うことを目的とした.特に、レンダリング技法の導入により,表示される立体像に隠面消去や陰影付け,金属やプラスティックなどの物体表面の質感や光沢などを立体像に付与することを中心として研究を行った.平成13年度および14年度の研究によって,以下の成果をあげた.1.ポリンゴンモデルで表された物体表面に乱数を基本とした方法によって,光の反射特性を付与する計算法を提案した.この計算法によって鏡面から完全拡散面までの様々な物体表面の質感が表現でき,よりリアルな立体像表示が可能となった.2.ポリゴンモデルを対象として隠面消去法である「影伝搬法」を提案した.これにより,裏側が透けて見える現象を除去し,複数の物体が存在する複雑な情景の立体表示への道を開いた.3.モデリング手法としてポリゴンモデルだけではなく,ボリュームデータモデルを対象とし,計算機合成ホログラムでのボリュームレンダリングアルゴリズムを提案した.これを医療用の3次元データに適用し,頭部立体像の表示に成功した.これには,上記の計算法が導入され,陰影付けや隠面消去などのレンダリングが実現されている.4.上記の計算法により得られたデータをマイクロフィルムに印字し、ホログラムを製作する手法を確立した.これを用いて立体像...
文部科学省, 萌芽的研究, 萌芽研究, 北海道大学, Principal investigator, Competitive research funding, 13875070

Development of a non-verbal communication technique using signlanguage and live CG techniques and its communication experiment across different languages using a communications satellite
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B).
1998 - 2000
AOKI Yoshinao, TANAHASHI Shin, SAKAMOTO Yuji, YAMAMOTO Tsuyoshi, HATSUDA Takeshi, FUJIWARA Yoshitaka, MITSUHASHI Ryuichi,takeshi, AOKI Naofumi, KAWASHIMA Toshio
The research results are listed as follows ;
(1) We proposed a new concept of 'avatar language' in relation to avatar technique in the Internet to realize a non-verbal communication, where gestures and emotional expressions of avatars are displayed using CG (computer graphics) animations.
(2) We developed a new programming language Lifo, which is a descendant of Lisp and Forth language to achieve high-speed processing in producing and displaying CG animations of avatar language.
(3) We developed a CG system for generating CG animations corresponding to words from avatar language in order to communicate across the linguistic barrier. A server-client system is developed for avatar-language communication using the developed CG system.
(4) We constructed an avatar-language chatting system using a software tool : MATLAB, where the system is constructed without complicated computer programming, resulting in simple chatting system.
(5) An experiment was conducted between avatars in Japanese and Korean environments to communicate using avatar language, resulting in collecting a basic data to develop a practical system of a non-verbal communication using avatar language in future.
(6) A communication experiment using Japanese communication satellite JCSAT was conducted to confirm the validity of the developed avatar-language chatting system.
(7) We proposed the virtual execution environment control system in order to apply to the avatar language communication via communication satellites, where responsiveness for the remote access was improved.
(8) We proposed a new estimation technique of urban shielding and satellite diversity characteristics for mobile broadcast geo-stationary satellite to obtain data for the practical use of communication satellite for avatar communication in future.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B)., HOKKAIDO UNIVERSITY, Coinvestigator not use grants, Competitive research funding, 10450142

Evaluation of Environmental Amenity for Animals based on Variability of Parameter of Physiological Function.
Grants-in-Aid for Scientific Research(一般研究(C))
1994 - 1995
Hiroshi TAZAWA, 坂本 雄児, 長島 知正
(1) As an experimental animal model, chick embryos were investigated for their physiological functions and growth to evaluate sdverse effects of pre-incubation egg storage and failure to turn eggs during the early incubation period.(2) Two-dimensional cardiogenic ballistic trajectories were elucidated by depicting them on a computer monitor screen from ballistic signals measured simultaneously at two sites on the eggshell with laser displacement meters.(3) Another simple method to measure the cardiogenic ballistic movements (BCG) of eggs was developed by taking advantage of an electromagnet...
Ministry of Education, Culture, Sports, Science and Technology, 一般研究(C), 室蘭工業大学, Coinvestigator not use grants, Competitive research funding, 06650448

無線通信システムおよび無線端末
Patent right, 坂本 雄児, 塚本 信夫, 滝川, 培久美子, 桑原 弘, 株式会社日立製作所
特願平1-131352, 26 May 1989
特開平3-054987, 08 Mar. 1991
特許第2852065号
13 Nov. 1998
201103059531381406