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Last Updated :2024/09/26

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Master

Affiliation (Master)

  • Faculty of Information Science and Technology　Systems Science and Informatics　Informatics for System Creation

Affiliation (Master)

  • Faculty of Information Science and Technology　Systems Science and Informatics　Informatics for System Creation

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Profile and Settings

Profile and Settings

  • Name (Japanese)

    Date

  • Name (Kana)

    Hiroaki

  • Name

    201201049119459977

Alternate Names

Achievement

Research Interests

  • レーザ計測点群   リバースエンジニアリング   CAD   サイバーフィールド   CAE   形状モデリング   

Research Areas

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Machine elements and tribology
  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Design engineering
  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Manufacturing and production engineering

Research Experience

  • 2019/04 - Today Fuculty of Information Science and Technology, Hokkaido University Division of Systems Science and Informatics Associate Professor
  • 2010/01 - 2019/03 Hokkaido University Graduate School of Information Science and Technology, Division of Systems Science and Informatics
  • 2007 - 2009/12 北海道大学 大学院・情報科学研究科 助教

Education

  • 2000/04 - 2003/03  Hokkaido University
  • 1998/04 - 2000/03  Hokkaido University
  •        - 1998/03  Hokkaido University  School of Engineering

Awards

  • 2022/06 19th Annual International CAD Conference CAD'22 Best Paper Award
     Shape Similarity Analysis and Standardization for Pre-bent Rod Design for Spinal Deformity Correction 
    受賞者: Ayane Soutome;Satoshi Kanai;Hiroaki Date;Hideki Sudo;Terufumi Kokabu;Yuichiro Abe;Hiroshi Moridaira;Hiroshi Taneichi
  • 2019/11 ICCCBEI2019 committee ICCBEI 2019 Best Paper Award Honorable Mentioned
     Automatic Indoor Environment Modeling from Laser-scanned Point Clouds using Graph-based Regular Arrangement Recognition 
    受賞者: Hayato Takahashi;Hiroaki Date;Satoshi Kanai
  • 2019/06 16th Annual International CAD Conference Best Paper Award
     Free-form Feature Classification for Finite Element Meshing based on Shape Descriptors and Machine Learning 
    受賞者: Ippei Takaishi;Satoshi Kanai;Hiroaki Date;Hideyoshi Takashima
  • 2018/07 CAD Conference Committee Best Paper Award
     Cylinder-based efficient and robust registration and model fitting of laser-scanned point clouds for as-built modeling piping system 
    受賞者: Ryota Moritani;Satoshi Kanai;Hiroaki Date;Masahiro Watanabe;Takahiro Nakano;Yuta Yaamuchi
  • 2017/09 精密工学会 北海道支部 精密工学会 北海道支部 技術賞
     X線CTと光学式計測データを併用した高品質ハイブリッド計測モデル生成技術の開発 
    受賞者: 杉本光祐;臼井一雅;髙嶋英厳;伊達宏昭;金井理
  • 2015/04 the ICCBEI Organizing Committee ICCBEI 2015 Best Paper Award
     Optimal setup of a terrestrial laser scanner for capturing piping objects in plants 
    受賞者: Satoshi Kanai;Shinya Yamanishi;Hiroaki Date
  • 2014/07 The Japan Society for Precision Engineering The 15th International Conference on Precision Engineering Best Paper Award
     MR-based 3D prototyping for information appliances using random dot markers and fingernaol color detection 
    受賞者: Satoshi Kanai;Hiroaki Date;Jiabin Guan
  • 2014/05 International Ergonomic Assosiation (IEA) Technical Committee (TC) on Human Simulation and Virtual Environment DHM2014 Basic Research Award
     Efficient large-scale as-build environment modeling based on 3D laser-scanning for human walking simulation 
    受賞者: Tsubasa Maruyama;Satoshi Kanai;Hiroaki Date
  • 2014/02 Gaheon Sindoh Foundation, Society of CAD/CAM Engineers The Gaheon Award 2013
     An Efficient Simulation of Skin Contact Deformation for Virtual Ergonomic Assessments of Handheld Products 
    受賞者: Yulai Xie;Satoshi Kanai;Hiroaki Date
  • 2013/05 Mobile Mapping Technology 2013 Best Presentation Award
     Segmentation of MMS Point Clouds of Urban Area based on Principal Component Analysis 
    受賞者: Hiroaki Date
  • 2013/03 (社)精密工学会 2012年度 精密工学会論文賞
     大規模環境レーザ計測点群からの配管系統の自動認識 
    受賞者: 川島千明;金井理;伊達宏昭
  • 2012/12 Asian Conference on Design and Digital Engineering 2012 The Best Paper Award
     Robust and Exhaustive Symmetry Detection from Scanned Meshes 
    受賞者: Tomihiro Mizoguchi;Satoshi Kanai;Hiroaki Date;Hiroyuki Tanaka
  • 2012/08 精密工学会 北海道支部 精密工学会 北海道支部 技術賞
     マイクロフォーカスX線CTシステムを用いた立体形状評価 
    受賞者: 田中大之;相山英明;万城目聡;金井理;伊達宏昭;溝口知広

Published Papers

  • MMS取得点群からの道路面における領域・線状型損のベクトルデータ抽出
    本間亮平, 伊達宏昭, 金井理
    精密工学会誌 89 (8) 654 - 660 2023/08 [Refereed]
  • FOOTPRINT DETECTION OF CEILING EQUIPMENT FROM TLS POINT CLOUDS
    R. Akiyama, H. Date, S. Kanai, K. Yasutake
    Proc. The Fifth International Conference on Civil and Building Engineering Informatics 465 - 470 2023/07 [Refereed]
  • Ryohei Honma, Hiroaki Date, Satoshi Kanai
    Seimitsu Kogaku Kaishi/Journal of the Japan Society for Precision Engineering 89 (8) 654 - 660 0912-0289 2023 
    It is important to accurately inspect road pavement conditions for maintaining the safety and comfort of drivers. In recent years, Mobile Mapping System (MMS) mounted with a laser scanner has been widely used and pavement defect extraction using MMS point clouds is expected. This paper presents an extraction method of region-type defects such as rutting and potholes and line-type defects such as cracks of pavement surfaces using point clouds acquired by a Mobile Mapping System. The features of the proposed method compared with related works are the ability to extract displacements of the region and line-type defects using a single framework and the ability to extract defects with different scales and complex geometries. The proposed method first estimates an ideal pavement surface based on smooth curve fitting to scanlines using an index that represents the impact level of defects at each point. Then, vector data of region and line-type defects are extracted using displacements from the ideal pavement surface at each point. In the experiments, the proposed method achieved an loll (Intersection over Union) of 80.2% for extracted regions and ground truth of region-type defects, and a recall of 90.7%, a precision of 97.0%, and an RMS of 10.0mm by Heipke's proposed method in the extraction of line-type defects.
  • Graph Neural Network-Based Finite Element Feature Recognition from B-rep Model
    Ryosuke Moriya, Satoshi Kanai, Hiroaki Date, Hideyoshi Takashima, Tetsufumi Taichi
    Proceedings of CAD'23 254 - 259 2023 [Refereed]
  • Preliminary Shape Similarity Analysis and Standardization for Pre-Bent Rod Design for Adult Spinal Deformity Correction
    A. Soutome, S. Kanai, H. Date, H. Sudo, T. Kokabu, Y. Abe, H. Moridaira, H. Taneichi
    Computer-Aided Design and Applications 20 (5) 797 - 813 2023 [Refereed][Not invited]
  • Xu, Yajun, Satoshi Kanai, Hiroaki Date, Tomoaki Sano
    Remote Sensing 14 (21) 5575  2022 [Refereed]
     
    Wave-dissipating blocks are the armor elements of breakwaters that protect beaches, ports, and harbors from erosion by waves. Monitoring the poses of individual wave-dissipating blocks benefits the accuracy of the block supplemental work plan, recording of the construction status, and monitoring of long-term pose change in blocks. This study proposes a deep-learning-based approach to detect individual blocks from large-scale three-dimensional point clouds measured with a pile of wave-dissipating blocks placed overseas and underseas using UAV photogrammetry and a multibeam echo-sounder. The approach comprises three main steps. First, the instance segmentation using our originally designed deep convolutional neural network partitions an original point cloud into small subsets of points, each corresponding to an individual block. Then, the block-wise 6D pose is estimated using a three-dimensional feature descriptor, point cloud registration, and CAD models of blocks. Finally, the type of each segmented block is identified using model registration results. The results of the instance segmentation on real-world and synthetic point cloud data achieved 70-90% precision and 50-76% recall with an intersection of union threshold of 0.5. The pose estimation results on synthetic data achieved 83-95% precision and 77-95% recall under strict pose criteria. The average block-wise displacement error was 30 mm, and the rotation error was less than 2 degrees. The pose estimation results on real-world data showed that the fitting error between the reconstructed scene and the scene point cloud ranged between 30 and 50 mm, which is below 2% of the detected block size. The accuracy in the block-type classification on real-world point clouds reached about 95%. These block detection performances demonstrate the effectiveness of our approach.
  • Personally Adapted Human Body Model Generation Based on 3D Body Scanning, Mesh Morphing, and Statistical Shape Model
    A. Sotome, S. Kanai, H. Date, Y. Endo
    Proceedings of the 19th international conference on precision engineering P-15  2022 [Refereed]
  • Efficient and Precise Approximated Object Model Generation for Optimal View Planning for SfM-MVS
    G. Yoshida, S. Kanai, H. Date
    Proceedings of the 19th international conference on precision engineering C175  2022 [Refereed]
  • Error ellipsoidal model estimation for TLS point clouds and its application to point cloud registration
    S. Yokomori, H. Date, S. Kanai, Y. Moribe
    Proceedings of the 19th international conference on precision engineering C240  2022 [Refereed][Not invited]
  • Feature Recognition from B-rep Models for Finite Element Meshing using Graph Neural Network
    R. Moriya, S. Kanai, H. Date, T. Taichi, H. Takashima
    Proceedings of the 19th international conference on precision engineering C282  2022 [Refereed]
  • Kenta Ohno, Hiroaki Date, Satoshi Kanai
    The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences Volume XLIII-B2-2022 251 - 258 2022 [Refereed][Not invited]
     
    Abstract. 3D point clouds from terrestrial laser scanners (TLS) are used in a variety of fields and applications. To acquire high-quality point clouds that have enough point density, small scanning errors, and no lack of points in important regions, appropriate scan planning, including determination of scanner positions and scan conditions, is required. Currently, planning is supported by knowledge and experience of skilled workers, and it is difficult to ensure the quality of acquired point clouds. In this study, we propose a system for visualization of point clouds to support the acquisition of high-quality point clouds using TLS. The system allows the user to see and check the quality of scanned TLS point clouds and unscanned regions intuitively by superimposing the point clouds onto the real world using a mixed reality (MR) device. In addition, the system supports finding the next best scanner position for additional laser scans based on predicted scan quality visualization to acquire higher-quality points or fill the unscanned regions.
  • Shape Similarity Analysis and Standardization for Pre-bent Rod Design for Spinal Deformity Correction
    Ayane Soutme, Satoshi Kanai, Hiroaki Date, Hideki Sudo, Terufumi Kokabu, Yuichiro Abe, Hiroshi Moridaira, Hiroshi Taneichi
    Proceedings of CAD'22 209 - 214 2022 [Refereed][Not invited]
  • Hiroaki Date, Tomohiro Mizoguchi, Kiichiro Ishikawa
    International Journal of Automation Technology 15 (3) 257  1883-8022 2021
  • Multi-view stereo reconstruction technique for weakly-textured surfaces
    Kei Akutsu, Satoshi Kanai, Hiroaki Date, Yoshihito Niina, Ryohei Honma
    Proceedings of the 10th International Conference on Bridge Maintenance, Safety and Management (IABMAS 2020) 2021 [Refereed][Not invited]
  • Tetsuro Ishikawa, Satoshi Kanai, Hiroaki Date
    Computer aided Design and Applications 18 (6) 1341 - 1358 2021 [Refereed][Not invited]
  • Kenta Ohno, Hiroaki Date, Satoshi Kanai
    International Journal of Automation Technology 15 (3) 324 - 333 2021 [Refereed][Not invited]
  • 本間亮平, 伊達宏昭, 金井理
    写真測量とリモートセンシング 日本写真測量学会 60 (2) 53 - 64 0285-5844 2021 [Refereed][Not invited]
  • Precise Denoising of 3D Point Clouds with Awareness of Point-Wise Measuring Quality
    Kohei Tsubooka, Satoshi Kanai, Hiroaki Date, Tatsuo Hariyama, Masahiro Watanabe
    Proceedings of the 18th International Conference on Precision Engineering 2020 [Refereed][Not invited]
  • Simple Textured Polygon Model Generation from Multiple TLS Point Clouds
    Shinichiro Imai, Hiroaki Date, Satoshi Kanai, Yoshinori Moribe, Masaki Nakamura
    Proceedings of the 18th International Conference on Precision Engineering 2020 [Refereed][Not invited]
  • Hayato Takahashi, Hiroaki Date, Satoshi Kanai, Kazunari Yasutake
    Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci. XLIII-B2-2020 495 - 500 2020 [Refereed]
     
    Abstract. Laser scanning technology is useful to create accurate three-dimensional models of indoor environments for applications such as maintenance, inspection, renovation, and simulations. In this paper, a detection method of indoor attached equipment such as windows, lightings, and fire alarms, from TLS point clouds, is proposed. In order to make the method robust against to the lack of points of equipment surface, a footprint of the equipment is used for detection, because the entire or a part of the footprint boundary shapes explicitly appear as the boundary of base surfaces, i.e. walls for windows, and ceilings for lightings and fire alarms. In the method, first, base surface regions are extracted from given TLS point clouds of indoor environments. Then, footprint boundary points are detected from the region boundary points. Finally, target equipment is detected by fitting or voting using given target footprint shapes. The features of our method are footprint boundary point extraction considering occlusions, shape fitting with adaptive parameters based on point intervals, and robust shape detection by voting from multiple footprint boundary candidates. The effectiveness of the proposed method is evaluated using TLS point clouds.
  • Ryohei Honma, Hiroaki Date, Satoshi Kanai
    Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci. XLIII-B2-2020 1091 - 1097 2020 [Refereed]
     
    Abstract. Efficient road edge extraction from point clouds acquired by Mobile Laser Scanning (MLS) is an important task because the road edge is one of the main elements of high definition maps. In this paper, we present a scanline-based road edge extraction method using a bend angle of scanlines from MLS point clouds. Scanline-based methods have advantages in that computational cost is low, it is easy to extract accurate road edges, and they are independent of driving speed of MLS compared to methods using unorganized points. In contrast, there are some problems with these methods where the extraction accuracy becomes low at curb cuts and intersections. The extraction accuracy becomes low caused by the scanning noise and small occlusion from weeds and fallen leaves. In addition, some parameters should be adjusted according to the mounting angle of the laser scanner on the vehicle. Therefore, we present a scanline-based road edge extraction method which can solve these problems. First, the points of the scanline are projected to a plane in order to reduce the influence of the mounting angle of the laser scanner on the vehicle. Next, the bend angle of each point is calculated by using filtered point clouds which are not vulnerable to small occlusions around the curb such as weeds. Then, points with a local maximum of bend angle and close to trajectories are extracted as seed points. Finally, road edges are generated by tracking based on bend angle of scanlines and smoothness of road edges from the seed points. In the experiments, our proposed methods achieved a completeness of over 95.3%, a correctness of over 95.0%, a quality of over 90.7%, and RMS difference less than 18.7 mm in total.
  • Ryota Moritani, Satoshi Kanai, Hiroaki Date, Yasuhito Niina, Ryohei Honma
    Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci. XLIII-B2-2020 465 - 471 2020 [Refereed]
     
    Abstract. Structure-from-Motion (SfM) and Multi-View Stereo (MVS) are widely used methods in three dimensional (3D) model reconstruction for an infrastructure maintenance purpose. However, if a set of images is not captured from well-placed positions, the final dense model can contain low-quality regions. Since MVS requires a much longer processing time than SfM as larger amounts of images are provided, it is impossible for surveyors to wait for the SfM–MVS process to complete and evaluate the geometric quality of a final dense model on-site. This challenge results in response inefficiency and the deterioration of dense models in 3D model reconstruction. If the quality of the final dense model can be predicted immediately after SfM, it will be possible to revalidate the images much earlier and to obtain the dense model with better quality than the existing SfM–MVS process. Therefore, we propose a method for reconstructing a more plausible 3D mesh model that accurately approximates the geometry of the final dense model only from sparse point clouds generated from SfM. This approximated mesh model can be generated using Delaunay triangulation for the sparse point clouds and triangle as well as tetrahedron filtering. The approximated model can be used to predict the geometric quality of the final dense model and for an optimization-based view planning. Some experimental results showed that our method is effective in predicting the quality of the final dense model and finding the potentially degraded regions. Moreover, it was confirmed that the average reconstruction errors of the dense model generated by the optimization-based view planning went below tens of millimeters and falls within an acceptable range for an infrastructure maintenance purpose.
  • Free-Form Feature Classification for Finite Element Meshing-based on Shape Descriptors and Machine Learning
    Ippei Takaishi, Satoshi Kanai, Hiroaki Date, Hideyoshi Takashima
    Computer-Aided Design and Applications 17 (5) 1049 - 1066 2020 [Refereed]
  • Automatic Indoor Environment Modeling from Laser-scanned Point Clouds using Graph-based Regular Arrangement Recognition
    Hayato Takahashi, Hiroaki Date, Satoshi Kanai
    Proceedings of the 4th International Conference on Civil and Building Engineering Informatics 368 - 375 2019/11 [Refereed][Not invited]
  • Segmentation and LOD model generation of buildings from MMS point clouds of urban area
    Takuya Kanayana, Toshihide Mineushiro, Hiroaki Date, Satoshi Kanai
    精密工学会誌 85 (10) 912 - 918 2019/10 [Refereed][Not invited]
  • QUALITY PREDICTION OF DENSE POINTS GENERATED BY STRUCTURE FROM MOTION FOR HIGH-QUALITY AND EFFICIENT AS-IS MODEL RECONSTRUCTION
    R. Moritani, S. Kanai, H. Date, Y. Niina, R. Honma
    Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci. XLII-2 (W13) 95 - 101 2019/06 [Refereed][Not invited]
  • MLS POINT CLOUD SEGMENTATION BASED ON FEATURE POINTS OF SCANLINES
    R. Honma, H. Date, S. Kanai
    Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci. XLII-2 (W13) 1007 - 1013 2019/06 [Refereed][Not invited]
  • TLS POINT CLOUD REGISTRATION BASED ON ICP ALGORITHM USING POINT QUALITY
    H. Date, E. Wakisaka, Y. Moribe, S. Kanai
    Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci. XLII-2 (W13) 963 - 968 2019/06 [Refereed][Not invited]
  • Optimal Laser Scan Planning for As-Built Modeling of Plant Renovations Using Mathematical Programming
    Eisuke Wakisaka, Satoshi Kanai, Hiroaki Date
    Proceedings of 2019 International Symposium on Automation and Robotics in Construction 91 - 98 2019/05 [Refereed][Not invited]
  • Free-form Feature Classification for Finite Element Meshing based on Shape Descriptors and Machine Learning
    Ippei Takaishi, Satoshi Kanai, Hiroaki Date, Hideyoshi Takashima
    Proc. 16th Annual International CAD Conference 414 - 419 2019/05 [Refereed][Not invited]
  • Fauzi Ahmad Ridwan, Kanai Satoshi, Date Hiroaki, Komizunai Shunsuke, Konno Atsushi, Colley Noriyo, Ninomiya Shinji
    Proceedings of JSPE Semestrial Meeting 公益社団法人 精密工学会 2019S 860 - 861 2019/03/01 
    Patients with cerebral palsy suffer from permanent movement disorder, and a nurse usually performs their tracheal aspiration where a tube must be inserted into the patient’s trachea. The tube insertion procedure must be performed quickly and carefully in order for the patient not to experience significant pain, anxiety, and even tracheal bleeding that would cause fear for the patient. To master such skill, many training opportunities should be provided for the novice nurses. Therefore, a training simulator is needed that could mimic the real situation of the procedure to provide an accurate and realistic feedback to the novice nurses. To realize that goal, we have developed a simulator that provides a head mannequin with the pain sensor attached and can project computer-generated patient’s facial expressions onto the mannequin face using projection mapping. The expression can change in conjunction with pain intensity the patient would receive due to the sputum blockage in the trachea and due to the hard contact of the tube tip with the trachea. The effectiveness of the projection mapping in the simulator is evaluated by comparing how fast trained and novice nurses finish the procedure when the facial expression of the pain is simulated or not.
  • 鋳造品の迅速リバースエンジニアリングに関する研究－鋳肌面と機械加工面の分離に基づく面属性付きの整形ソリッドモデルの生成－
    浦田昇尚, 伊達宏昭, 金井理, 後藤孝行, 安田星季
    精密工学会誌 85 (3) 267 - 273 2019/03 [Refereed][Not invited]
  • Kazuya Kobayashi, Satoru Wakasa, Koji Sato, Satoshi Kanai, Hiroaki Date, Satomi Kimura, Noriko Oyama-Manabe, Yoshiro Matsui
    Physics in medicine and biology 64 (5) 055009 - 055009 2019/02/25 [Refereed][Not invited]
     
    Regional cardiac function analysis is important for the diagnosis and treatment planning of ischemic heart disease, but has not been sufficiently developed in the field of computed tomography (CT). Therefore, we propose a 3D endocardial tracking framework for cardiac CT using local point cloud registration based on the iterative closest point with an integrated scale estimation algorithm. We also introduce regional function descriptors that express the curvature and stretching of the endocardium: Surface distortion (E) and Scaling rate (S). For a region-to-region comparison, we propose endocardial segmentation according to coronary perfusion territories defined by the Voronoi partition based on coronary distribution. Our study of 65 endocardial segments in ten subjects showed that global endocardial deformation has a positive relationship with the stroke volume index (r  =  0.896 and 0.829 in [Formula: see text] and [Formula: see text], respectively) and ejection fraction (r  =  0.804 and 0.835), and a positive relationship with the brain natriuretic peptide level (r  =  0.690 and 0.776). A positive relationship between segmental E and S (r  =  0.845), a higher value of E in ischemic segments (p   =  0.021) that are determined by fractional flow reserve estimated from coronary CT data, and a higher value of S in the left circumflex artery territory (p   <  0.05) were also observed. The required radiation dose was 5.0  ±  0.7 mSv and the computation time was 7.2  ±  1.1 min. The result suggests that proposed endocardial deformation analysis using CT can be conducted on site and in time for the acute setting, and may be useful for the diagnosis of cardiac dysfunction or myocardial ischemia.
  • Ryota Moritani, Satoshi Kanai, Hiroaki Date, Masahiro Watanabe, Takahiro Nakano, Yuta Yamauchi
    Computer-Aided Design & Applications CAD} Solutions, {LLC 16 (3) 396 - 412 2019/01 [Refereed][Not invited]
  • Optimal Laser Scan Planning of Terrestrial Laser Scanner for As-built Modeling of HVAC Systems using Integer Programming
    Eisuke Wakisaka, Satoshi Kanai, Hiroaki Date
    Proc. International Conference on Precision Engineering D-5-4  2018/11 [Refereed][Not invited]
  • Development of Fast Posture Change Method for FE-Model of the Human Body Based on Mesh Deformation
    Kazuma Hirosawa, Mitsunori Tada, Natsuki Miyata, Satoshi Kanai, Hiroaki Date
    Proc. Asian Conference on Design and Digital Engineering PaperID_27  2018/11 [Refereed][Not invited]
  • Segmentation and LOD Model Generation of Buildings from MMS Point Clouds of Urban Area
    Takuya Kanayama, Toshihide Mineushiro, Hiroaki Date, Satoshi Kanai
    Proc. International Conference on Precision Engineering D-5-3  2018/11 [Refereed][Not invited]
  • Ryota Moritani, Satoshi Kanai, Hiroaki Date, Masahiro Watanabe, Takahiro Nakano, Yuta Yamauchi
    Computer-Aided Design and Applications 15 (5) 720 - 733 1686-4360 2018/09/03 [Refereed][Not invited]
     
    In this study, a novel algorithm for cylinder-based registration and model fitting of laser-scanned point clouds was proposed. The algorithm was designed specifically for as-built modeling of a plant piping system. In contrast with Iterative Closest Point (ICP)-based methods, fine registration and model fitting were performed simultaneously, by solving a single nonlinear constraint equation. This prevented alignment error arising in registration from propagating to model fitting. Coarse registration was automated by identifying cylindrical surfaces and by finding matches among their cylinder axes using a random sample consensus (RANSAC) method. The accuracy and robustness of the proposed algorithm was first confirmed using scan simulations. It performed well even when there was zero overlap between scans, and was demonstrated to achieve better modeling accuracy than ICP-based methods. The algorithm was then applied to point clouds scanned from a real plant, with successful results. The proposed algorithm achieves as-built modeling accuracies that would be fully acceptable when conducting renovation work on existing piping systems.
  • 空調設備のas-builtモデル構築のための地上型レーザスキャナの最適配置計画
    脇坂 英佑, 金井 理, 伊達 宏昭
    精密工学会誌 84 (8) 738 - 745 2018/08 [Refereed][Not invited]
  • Cylinder-based Efficient And Robust Registration And Model Fitting Of Laser-scanned Point Clouds For As-built Modeling Of Piping Systems
    Ryota Moritani, Satoshi Kanai, Hiroaki Date, Masahiro Watanabe, Takahiro Nakano, Yuta Yamauchi
    Proc. CAD'18 262 - 267 2018/07 [Refereed][Not invited]
  • Generation Of Solid Models With Surface Properties From Scanned Triangular Meshes Of Castings
    Akihisa Urata, Hiroaki Date, Satoshi Kanai
    Proc. CAD'18 342 - 346 2018/07 [Refereed][Not invited]
  • Automated recognition and 3D CAD modeling of standardized steel bridge members in a laser scan
    Satoshi Kanai, Motoaki Hashikawa, Hiroaki Date
    Proc. 17th International Conference on Computing in Civil and Building Engineering 2018/06 [Refereed][Not invited]
  • MULTIPLE TLS POINT CLOUD REGISTRATION BASED ON POINT PROJECTION IMAGES
    Taiki Sumi, Hiroaki Date, Satoshi Kanai
    Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci. XLII-2 1083 - 1090 2018/06 [Refereed][Not invited]
  • Eisuke Wakisaka, Satoshi Kanai, Hiroaki Date
    Computer-Aided Design and Applications 15 (3) 353 - 366 1686-4360 2018/05/04 [Refereed][Not invited]
     
    Recently, terrestrial laser scanners (TLSs) have been introduced to efficient as-built three-dimensional (3D) modeling in the heating, ventilating, and air-conditioning (HVAC) industry. When scanning the highly tangled installation of piping objects in HVAC systems using TLS, it is difficult to manually decide feasible scanner placement to scan the necessary regions of objects for construction with high accuracy and high point density and without any occlusion. Therefore, in this paper, we propose a model-based next-best-view planning method for TLS. The method uses a coarse 3D model generated by structure-from-motion (SfM), and it finds the near-optimum scanner placement that maximizes scan coverage while satisfying the constraints on the factors influencing scan quality such as beam incident angle, scan range, and scan overlap. The constraints are imposed based on user-specified scanning priority levels. Scanner placement is determined based on voxel-based space occupancy classification. The superiority of scanner placement by using the proposed method is verified through a comparative evaluation of the modeling accuracy with scanner placement by an experienced operator.
  • Bridge Information Modeling based on IFC for supporting maintenance management of existing bridges
    Fumiki Tanaka, Makoto Tsuchida, Masahiko Onosato, Hiroaki Date, Satoshi Kanai, Yoshiro Hada, Manabu Nakao, Hiroki Kobayashi, Eiji Hasegawa, Toshiya Sugawara, Takateru Oyama
    Proceedings of ICCCBE 2018 2018 [Refereed]
  • Tsubasa Maruyama, Satoshi Kanai, Hiroaki Date
    Automation in Construction 85 193 - 208 0926-5805 2018/01/01 [Refereed][Not invited]
     
    Tripping-related falls are the leading cause of unintentional deaths in the elderly. Tripping risk must be evaluated by considering intrinsic and extrinsic factors affecting the interactions between humans and the environment. The goal of this study is to develop a new tripping risk evaluation system based on human behavior simulation in an “as-is” environment model, i.e., environment model reflecting detailed environmental geometry. First, a three-dimensional (3D) as-is environment model is automatically constructed from laser-scanned point clouds in the environment. From this model, potential tripping-hazard regions are automatically detected. Finally, the tripping risk of detected hazard region is quantitatively evaluated based on a combined human behavior and Monte Carlo simulation. The simulated tripping risk is compared with that measured using real humans, and it is revealed that the dimensional limit of risk evaluation accuracy in terms of barrier height on a walking terrain is very close to 10 mm.
  • Hiroaki Date, Takahito Yokoyama, Satoshi Kanai, Yoshiro Hada, Manabu Nakao, Toshiya Sugawara
    International Journal of Automation Technology 12 (3) 328 - 338 2018 [Refereed][Not invited]
  • Tsubasa Maruyama, Satoshi Kanai, Hiroaki Date, Mitsunori Tada
    ISPRS INTERNATIONAL JOURNAL OF GEO-INFORMATION 6 (9) 267 - 288 2220-9964 2017/09 [Refereed][Not invited]
     
    As recommended by the international standards, ISO 21542, ease of wayfinding must be ensured by installing signage at all key decision points on walkways such as forks because signage greatly influences the way in which people unfamiliar with an environment navigate through it. Therefore, we aimed to develop a new system for evaluating the ease of wayfinding, which could detect spots that cause disorientation, i.e., "disorientation spots", based on simulated three-dimensional (3D) interactions between wayfinding behaviors and signage location, visibility, legibility, noticeability, and continuity. First, an environment model reflecting detailed 3D geometry and textures of the environment, i.e., "as-is environment model", is generated automatically using 3D laser-scanning and structure-from-motion (SfM). Then, a set of signage entities is created by the user. Thereafter, a 3D wayfinding simulation is performed in the as-is environment model using a digital human model (DHM), and disorientation spots are detected. The proposed system was tested in a virtual maze and a real two-story indoor environment. It was further validated through a comparison of the disorientation spots detected by the simulation with those of six young subjects. The comparison results revealed that the proposed system could detect disorientation spots, where the subjects lost their way, in the test environment.
  • Yoshiro Hada, Manabu Nakao, Moyuru Yamada, Hiroki Kobayashi, Naoyuki Sawasaki, Katsunori Yoko Ji, Satoshi Kanai, Fumiki Tanaka, Hiroaki Date, Sarthak Pathak, Atsushi Yamashita, Manabu Yamada, Toshiya Sugawara
    Journal of Disaster Research 12 (3) 593 - 606 1883-8030 2017/06/01 [Refereed][Not invited]
     
    Recently, many countries have faced serious problems associated with aging civil infra structures such as bridges, tunnels, dams, highways and so on. Aging infrastructures are increasing year by year and suitable maintenance actions are necessary to maintain their safety and serviceability. In fact, infrastructure deterioration has caused serious problems in the past. In order to prevent accidents with civil infrastructures, supervisors must spend a lot of money to maintain the safe conditions of infrastructures. Therefore, new technologies are required to reduce maintenance costs. In 2014 the Japanese government started the Cross-Ministerial Strategic Innovation Promotion Program (SIP), and technologies for infrastructure maintenance have been studied in the SIP project [1]. Fujitsu Limited, Hokkaido University, The University of Tokyo, Nagoya Institute of Technology and Docon Co. Limited have been engaged in the SIP project to develop a bridge inspection support system using information technology and robotic technology. Our system is divided into the following two main parts: bridge inspection support robots using a two-wheeled multicopter, and an inspection data management system utilizing 3D modeling technology. In this paper, we report the bridge inspection support system developed in our SIP project.
  • URATA Akihisa, DATE Hiroaki, KANAI Satoshi, GOTOH Takayuki, YASUDA Seiki
    Journal of the Japan Society for Precision Engineering 公益社団法人 精密工学会 83 (5) 474 - 480 2017/05 [Refereed][Not invited]
     
    Recently, it has become necessary to develop a more advanced reverse engineering (RE) technique that can generate CAD models of complex shapes from scanned mesh more efficiently. In this study, we propose a new efficient reverse engineering method of castings. In the method, machining and casting surfaces of the scanned mesh are separated, and precise surface fitting is applied only to the machining surfaces. The method can realizes an efficient RE process since different geometric processing and modeling techniques can be applicable to machining and casting surfaces individually. In addition, suitable geometric processes in the applications of the CAD models, such as machining margin addition and machining planning for machining surfaces in the duplication, can be automatically applied to each machining and casting surfaces, because they are recognized in our method. In this paper, we develop two methods. First, the surfaces are classified into the casting and machining surfaces based on triangle roughness. Second, boundaries of the casting surfaces are smoothed and modified so as to intersect machining surfaces for generation of the CAD models. We show some experimental results using some scanned meshes of castings.
  • Hiroki Maehama, Hiroaki Date, Satoshi Kanai
    JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING 11 (4) JAMDSM0045  1881-3054 2017 [Refereed][Not invited]
     
    In current product design, CAE based on FEA has become absolutely imperative for developing high quality products. In some analyses of assembly models with movable parts such as electro-magnetic field analyses of motors, conformal tetrahedral meshes including meshes both of objects (parts) and space (called "object mesh" and "space mesh" in this paper) are needed. In general CAE processes, poses of moving parts of CAD models are first modified, then conformal meshes of the modified CAD models are generated, and FEAs are finally performed at each pose of the object in motion. However, simultaneous conformal meshing for objects and spaces is unstable and time-consuming. To reduce the frequency of the meshing, many mesh adaptation methods have been proposed. Although they can generate the conformal mesh of each object pose by modifying the mesh connectivity and vertex positions depending on the object motion, they are inefficient because the mesh topology and geometry are globally adapted even if the differences in poses of the objects in motion are very small In addition, they do not deal with contacts of the object meshes. In this paper, we propose a new efficient tetrahedral mesh adaptation method for moving objects with contact. For efficient mesh adaptation, the mesh adaptation process is applied to only a set of space mesh elements around the moving object based on a distance field. In addition, to keep mesh conformity on the contact regions between object meshes, the topology and geometry of surface triangular meshes of contacted object meshes are adapted by vertex repositioning and local topological operations. The proposed method is demonstrated using three samples. In an experimental result where a cylinder is translated toward a half tube, the conformal tetrahedral meshes with 160k tetrahedra were generated without any inverted elements for about 5 seconds in each motion step.
  • Automatic Registration of Laser-Scanned Point Clouds of Bridges using Linear Features
    H. Date, T. Yokoyama, S. Kanai, Y. Hada, M. Nakao, T. Sugawara
    2016 Asian Conference on Design and Digital Engineering 18-6  2016/10 [Not refereed][Not invited]
  • Efficient Conformal Tetrahedral finite Element mesh Generation for Moving Object with Contact by Mesh Adaptation
    H. Maehama, H. Date, S. Kanai
    2016 Asian Conference on Design and Digital Engineering 13-5  2016/10 [Not refereed][Not invited]
  • Reiji Yoshimura, Hiroaki Date, Satoshi Kanai, Ryohei Honma, Kazuo Oda, Tatsuya Ikeda
    Geo-Spatial Information Science 19 (3) 171 - 181 1009-5020 2016/07/02 [Refereed][Not invited]
     
    Recent advances in 3D scanning technologies allow us to acquire accurate and dense 3D scan data of large-scale environments efficiently. Currently, there are various methods for acquiring large-scale 3D scan data, such as Mobile Laser Scanning (MLS), Airborne Laser Scanning, Terrestrial Laser Scanning, photogrammetry and Structure from Motion (SfM). Especially, MLS is useful to acquire dense point clouds of road and road-side objects, and SfM is a powerful technique to reconstruct meshes with textures from a set of digital images. In this research, a registration method of point clouds from vehicle-based MLS (MLS point cloud), and textured meshes from the SfM of aerial photographs (SfM mesh), is proposed for creating high-quality surface models of urban areas by combining them. In general, SfM mesh has non-scale information therefore, scale, position, and orientation of the SfM mesh are adjusted in the registration process. In our method, first, 2D feature points are extracted from both SfM mesh and MLS point cloud. This process consists of ground- and building-plane extraction by region growing, random sample consensus and least square method, vertical edge extraction by detecting intersections between the planes, and feature point extraction by intersection tests between the ground plane and the edges. Then, the corresponding feature points between the MLS point cloud and the SfM mesh are searched efficiently, using similarity invariant features and hashing. Next, the coordinate transformation is applied to the SfM mesh so that the ground planes and corresponding feature points are adjusted. Finally, scaling Iterative Closest Point algorithm is applied for accurate registration. Experimental results for three data-sets show that our method is effective for the registration of SfM mesh and MLS point cloud of urban areas including buildings.
  • Laser-scanned as-built 3D modeling of air-conditioning ducts based on Manhattan world assumption
    M. Narumi, S. Kanai, H. Date, E. Wakisaka, S. Sakamoto
    15th International Conference on Computing in Civil and Building Engineering 287  2016/07 [Refereed][Not invited]
  • Bridge Information Model Based on IFC Standards and Web Content Providing System for Supporting an Inspection Process
    Fumiki Tanaka, Masato Hori, Masahiko Onosato, Hiroaki Date, Satoshi Kanai
    Proceedings of ICCCBE 2016 [Refereed]
  • KANAI Satoshi, HATAKEYAMA Ryu, DATE Hiroaki
    Journal of the Japan society of photogrammetry and remote sensing 一般社団法人 日本写真測量学会 55 (4) 235 - 239 0285-5844 2016 [Refereed][Not invited]
     

    The purpose of this study is to improve an accuracy and efficiency of 6DOF motion estimation in 3D MCL for indoor localization. Firstly, a terrestrial laser scanner is used for creating a precise 3D mesh model as an environment map, and a professional-level depth camera is installed as an outer sensor. GPU scene simulation is also introduced to upgrade the speed of prediction phase in MCL. Moreover, for further improvement, GPGPU programming is implemented to realize further speed up of the likelihood estimation phase, and anisotropic particle propagation is introduced into MCL based on the observations from an inertia sensor. Improvements in the localization accuracy and efficiency are verified by the comparison with a previous MCL method. The results showed that our proposed 3D MCL method outperforms the previous one in accuracy and efficiency.

  • Tsubasa Maruyama, Satoshi Kanai, Hiroaki Date
    PROCEEDINGS OF THE ASME INTERNATIONAL DESIGN ENGINEERING TECHNICAL CONFERENCES AND COMPUTERS AND INFORMATION IN ENGINEERING CONFERENCE, 2016, VOL 1A IDETC2016-59170  2016 [Refereed][Not invited]
     
    Elderly and disabled individuals must be able to access the indoor and outdoor environment in an easy and safe manner. Accessibility must be assessed not only in terms of physical friendliness for users, but also of cognitive friendliness such as the ease of wayfinding. To ensure the ease of wayfinding, signage information available at every key decision point is essential because it enables people to find their way in unfamiliar environment. The aim of the present study is to develop virtual accessibility evaluation system that evaluates the environment accessibility from the cognitive friendliness aspect, such as the ease of wayfinding, by combining realistic human behavior simulation using a digital human model (DHM) with as-is environment models. To realize this system, we develop a vision-based wayfinding simulation algorithm for the DHM in textured three-dimensional (3D) as-is, environment models. The as-is environment models are constructed with the structure-from-motion (SfM) technique. During the wayfinding simulation, the visibility and legibility of each sign are evaluated on the basis of the visual perception of the DHM and its visibility catchment area (VCA). The DHM walking trajectory is dynamically generated depending on the perceived sign. When a disorientation place is detected where the DHM cannot find any sign indicating its destination, plans for rearranging the signs are proposed by the simulation user and then examined using a developed virtual eyesight simulator (VES). The VES enables the user to check the DHM eyesight virtually during the wayfinding simulation through a head mounted display. To mimic visual impairments, visual impairment filters are introduced into the VES. In this paper, we demonstrate the process of detecting the disorientation place, and planning and evaluating the rearranged signage.
  • Tsubasa Maruyama, Satoshi Kanai, Hiroaki Date, Mitsunori Tada
    J. Computational Design and Engineering 3 (3) 250 - 265 2016 [Refereed][Not invited]
  • Automatic Registration of MLS Point Clouds and SfM Meshes of Urban Area
    R. Yoshimura, H. Date, S. Kanai, R. Honma, K. Oda, T. Ikeda
    The 9th International Symposium on Mobile Mapping Technology #195  2015/12 [Not refereed][Not invited]
  • Automatic Robust Registration of MLS Point Clouds of Urban Area
    H. Date, S. Takai, S. Kanai, R. Honma, K. Oda, T. Ikeda
    The 9th International Symposium on Mobile Mapping Technology #201  2015/12 [Not refereed][Not invited]
  • Surface extraction based on roughness for rapid reverse engineering of castings
    A. Urata, S. Kanai, H. Date, T.Gotoh, S.Yasuda
    2015 Asian Conference on Design and Digital Engineering 40 2015/11 [Refereed][Not invited]
  • Motion-capture-based walking simulation adapted to laser-scanned large-scale complex as-built environments for accessibility evaluation
    T. Maruyama, S. Kanai, H. Date, Mitsunori Tada
    Proc. of 8th Asian-Pacific Conference on Biomechanics PS3-15  2015/09 [Not refereed][Not invited]
  • Satoshi Kanai, R. Hatakeyama, H. Date
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives 40 (4) 61 - 66 1682-1750 2015/05/11 [Refereed][Not invited]
     
    Effective and accurate localization method in three-dimensional indoor environments is a key requirement for indoor navigation and lifelong robotic assistance. So far, Monte Carlo Localization (MCL) has given one of the promising solutions for the indoor localization methods. Previous work of MCL has been mostly limited to 2D motion estimation in a planar map, and a few 3D MCL approaches have been recently proposed. However, their localization accuracy and efficiency still remain at an unsatisfactory level (a few hundreds millimetre error at up to a few FPS) or is not fully verified with the precise ground truth. Therefore, the purpose of this study is to improve an accuracy and efficiency of 6DOF motion estimation in 3D MCL for indoor localization. Firstly, a terrestrial laser scanner is used for creating a precise 3D mesh model as an environment map, and a professional-level depth camera is installed as an outer sensor. GPU scene simulation is also introduced to upgrade the speed of prediction phase in MCL. Moreover, for further improvement, GPGPU programming is implemented to realize further speed up of the likelihood estimation phase, and anisotropic particle propagation is introduced into MCL based on the observations from an inertia sensor. Improvements in the localization accuracy and efficiency are verified by the comparison with a previous MCL method. As a result, it was confirmed that GPGPU-based algorithm was effective in increasing the computational efficiency to 10-50 FPS when the number of particles remain below a few hundreds. On the other hand, inertia sensor-based algorithm reduced the localization error to a median of 47mm even with less number of particles. The results showed that our proposed 3D MCL method outperforms the previous one in accuracy and efficiency.
  • Optimal setup of a terrestrial laser scanner for capturing piping objects in plants
    S. Kanai, S. Yamanishi, H. Date
    Proc. of the 2nd International Conference on Civil and Building Engineering Informatics #30  2015/04 [Refereed][Not invited]
  • S. Kanai, R. Hatakeyama, H. Date
    Indoor-Outdoor Seamless Modelling, Mapping and Navigation 44 (W5) 61 - 66 2194-9034 2015 [Refereed][Not invited]
     
    Effective and accurate localization method in three-dimensional indoor environments is a key requirement for indoor navigation and lifelong robotic assistance. So far, Monte Carlo Localization (MCL) has given one of the promising solutions for the indoor localization methods. Previous work of MCL has been mostly limited to 2D motion estimation in a planar map, and a few 3D MCL approaches have been recently proposed. However, their localization accuracy and efficiency still remain at an unsatisfactory level (a few hundreds millimetre error at up to a few FPS) or is not fully verified with the precise ground truth. Therefore, the purpose of this study is to improve an accuracy and efficiency of 6DOF motion estimation in 3D MCL for indoor localization. Firstly, a terrestrial laser scanner is used for creating a precise 3D mesh model as an environment map, and a professional-level depth camera is installed as an outer sensor. GPU scene simulation is also introduced to upgrade the speed of prediction phase in MCL. Moreover, for further improvement, GPGPU programming is implemented to realize further speed up of the likelihood estimation phase, and anisotropic particle propagation is introduced into MCL based on the observations from an inertia sensor. Improvements in the localization accuracy and efficiency are verified by the comparison with a previous MCL method. As a result, it was confirmed that GPGPU-based algorithm was effective in increasing the computational efficiency to 10-50 FPS when the number of particles remain below a few hundreds. On the other hand, inertia sensor-based algorithm reduced the localization error to a median of 47mm even with less number of particles. The results showed that our proposed 3D MCL method outperforms the previous one in accuracy and efficiency.
  • 前濱宏樹, 伊達宏昭, 金井理
    精密工学会誌 81 (4) 368 - 375 2015 [Refereed][Not invited]
  • Tsubasa Maruyama, Satoshi Kanai, Hiroaki Date
    Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 9185 193 - 204 1611-3349 2015 [Refereed][Not invited]
     
    Accessibility evaluation to enhance accessibility and safety for the elderly and disabled is increasing in importance. Accessibility must be assessed not only from the general standard aspect but also in terms of physical and cognitive friendliness for users of different ages, genders, and abilities. Human behavior simulation has been progressing in crowd behavior analysis and emergency evacuation planning. This research aims to develop a virtual accessibility evaluation by combining realistic human behavior simulation using a digital human model (DHM) with as-built environmental models. To achieve this goal, we developed a new algorithm for generating human-like DHM walking motions, adapting its strides and turning angles to laser-scanned as-built environments using motion-capture (MoCap) data of flat walking. Our implementation quickly constructed as-built three-dimensional environmental models and produced a walking simulation speed sufficient for real-time applications. The difference in joint angles between the DHM and MoCap data was sufficiently small. Demonstrations of our environmental modeling and walking simulation in an indoor environment are illustrated.
  • Variational hand modeling and its application to statistical analysis of grasp comfort
    S. Kanai, Y. Xie, H.Date
    Proc. of 2014 Asian Conference on Design and Digital Engineering S08  2014/10 [Not refereed][Not invited]
  • Enabling human-like walking of digital human model in laser-scanned large-scale as-built environment
    T. Maruyama, S. Kanai, H. Date
    Proc. of 2014 Asian Conference on Design and Digital Engineering S05  2014/10 [Not refereed][Not invited]
  • Registration of Point Clouds of Large Scale Environments using Point Projection Images
    H. Date, Y. Matsuyama, S. Kanai
    Proc. of the 15th International Conference on Precision Engineering D31  2014/07 [Refereed][Not invited]
  • Segmentation, Dimension-Driven Deformation, and Quality Improvement of Tetrahedral Mesh Models for Finite Element Analysis
    H. Maehama, H. Date, S. Kanai
    Proc. of the 15th International Conference on Precision Engineering D30  2014/07 [Refereed][Not invited]
  • MR-based 3D prototyping for information appliances using random dot markers and fingernail color detection
    S. Kanai, H. Date, J. Guan
    Proc. of the 15th International Conference on Precision Engineering P37  2014/07 [Refereed][Not invited]
  • Estimating Grasp Comfort using 3D Geometric and Musculoskeletal Models of the Human Hand
    S. Kanai, Y. Xie, H. Date
    Proc. of Digital Human Modeling Symposium 2014 #37  2014/05 [Not refereed][Not invited]
  • Hiroaki Date, Takashi Maeno, Satoshi Kanai
    Computer-Aided Design and Applications 11 (6) 685 - 693 1686-4360 2014/01/01 [Refereed][Not invited]
     
    In this paper, a rendering method of the laser scanned point clouds of large scale environments is proposed for supporting an easy and intuitive understanding of the scanned environments. In this method, an adaptive primitives selection model and hierarchical point representation are used in the rendering of the scanned environment. Local geometry of the objects are estimated by principal component analysis, and the graphic primitives for points are adaptively created for effective rendering. View-dependent LOD using point hierarchy and an adaptive primitives selection model are also achieved for efficient rendering. Some rendering results for point clouds acquired from different scanning systems are shown and compared with other methods.
  • Hiroki Maehama, Hiroaki Date, Satoshi Kanai
    Computer-Aided Design and Applications 11 (6) 622 - 631 1686-4360 2014/01/01 [Refereed][Not invited]
     
    ABSTRACT: For realizing efficient product shape design, many dimension-driven mesh deformation methods have been proposed. However, the deformed mesh models often include many distorted elements, and lose the original mesh properties (mesh density and shape approximation accuracy). To solve these problems, we propose a quality improvement method for the deformed tetrahedral mesh models. Our method is based on Optimal Delaunay Triangulation (ODT) smoothing with edge split and edge collapse. In our method, element shape qualities are improved from the boundary to the inside of the mesh model, and original mesh properties are recovered in the deformed mesh models by an additional step in the ODT smoothing. In addition, degenerated and inverted elements are removed by local topological operations. The effectiveness of our method is demonstrated by applications to some simple mesh models.
  • Satoshi Kanai, Hiroaki Date
    PROCEEDINGS OF THE ASME INTERNATIONAL DESIGN ENGINEERING TECHNICAL CONFERENCES AND COMPUTERS AND INFORMATION IN ENGINEERING CONFERENCE, 2013, VOL 2B DETC2013-12931  2014 [Refereed][Not invited]
     
    Recently 3D digital prototypes of information appliances have been proposed for efficient user acceptance tests of user-interface (UI) usability. The purpose of this research is to develop a gaze estimation system based on Homography and to fully integrate it with a 3D digital prototype of the information appliances in order to obtain information more useful for usability assessment. The estimation system consists only of four infrared LEDs and a USB camera and is low-cost. The gaze estimation enables the system not only to record a gaze point on the prototype but to identify the UI objects which the user is looking for in real time during the test session. A gaze-based index was newly introduced to identify the misleading UI objects and to quantify the irrelevance of the UI design. A case study suggested that the integration of the gaze estimation with the 3D digital prototype and the proposed index were useful for automatically identifying which irrelevant UI objects misled the users' operations which could not yet be captured in previous simple event logging of the user inputs.
  • K. Kawashima, S. Yamanishi, S. Kanai, H. Date
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives 40 (5) 313 - 320 1682-1750 2014 [Refereed][Not invited]
     
    Renovation of plant equipment of petroleum refineries or chemical factories have recently been frequent, and the demand for 3D as-built modelling of piping systems is increasing rapidly. Terrestrial laser scanners are used very often in the measurement for as-built modelling. However, the tangled structures of the piping systems results in complex occluded areas, and these areas must be captured from different scanner positions. For efficient and exhaustive measurement of the piping system, the scanner should be placed at optimum positions where the occluded parts of the piping system are captured as much as possible in less scans. However, this "next-best" scanner positions are usually determined by experienced operators, and there is no guarantee that these positions fulfil the optimum condition. Therefore, this paper proposes a computer-aided method of the optimal sequential view planning for object recognition in plant piping systems using a terrestrial laser scanner. In the method, a sequence of next-best positions of a terrestrial laser scanner specialized for as-built modelling of piping systems can be found without any a priori information of piping objects. Different from the conventional approaches for the next-best-view (NBV) problem, in the proposed method, piping objects in the measured point clouds are recognized right after an every scan, local occluded spaces occupied by the unseen piping systems are then estimated, and the best scanner position can be found so as to minimize these local occluded spaces. The simulation results show that our proposed method outperforms a conventional approach in recognition accuracy, efficiency and computational time.
  • 丸山翼, 金井理, 伊達宏昭
    精密工学会誌 80 (8) 755 - 762 2014 [Refereed][Not invited]
  • Hiroaki Date, Takashi Maeno, Satoshi Kanai
    Computer-Aided Design and Applications 11 (6) 685 - 693 1686-4360 2014/01/01 [Refereed][Not invited]
     
    In this paper, a rendering method of the laser scanned point clouds of large scale environments is proposed for supporting an easy and intuitive understanding of the scanned environments. In this method, an adaptive primitives selection model and hierarchical point representation are used in the rendering of the scanned environment. Local geometry of the objects are estimated by principal component analysis, and the graphic primitives for points are adaptively created for effective rendering. View-dependent LOD using point hierarchy and an adaptive primitives selection model are also achieved for efficient rendering. Some rendering results for point clouds acquired from different scanning systems are shown and compared with other methods.
  • Hiroki Maehama, Hiroaki Date, Satoshi Kanai
    Computer-Aided Design and Applications 11 (6) 622 - 631 1686-4360 2014/01/01 [Refereed][Not invited]
     
    ABSTRACT: For realizing efficient product shape design, many dimension-driven mesh deformation methods have been proposed. However, the deformed mesh models often include many distorted elements, and lose the original mesh properties (mesh density and shape approximation accuracy). To solve these problems, we propose a quality improvement method for the deformed tetrahedral mesh models. Our method is based on Optimal Delaunay Triangulation (ODT) smoothing with edge split and edge collapse. In our method, element shape qualities are improved from the boundary to the inside of the mesh model, and original mesh properties are recovered in the deformed mesh models by an additional step in the ODT smoothing. In addition, degenerated and inverted elements are removed by local topological operations. The effectiveness of our method is demonstrated by applications to some simple mesh models.
  • Kazuaki Kawashima, Satoshi Kanai, Hiroaki Date
    Journal of Computational Design and Engineering 1 (1) 13 - 26 2288-5048 2014/01/01 [Refereed][Not invited]
     
    Recently, renovations of plant equipment have been more frequent because of the shortened lifespans of the products, and as-built models from large-scale laser-scamied data is expected to streamline rebuilding processes. However, the laser-scanned data of an existing plant has an enormous amount ofpoints, captures inmcate objects, and includes a high noise level, so the manual reconstmction of a 3D model is very time-consuming and costly. Among plant equipment, piping systems account for the greatest proportion. Therefore, the purpose of this research was to propose an algorithm which could automatically recognize a piping system from the terrestrial laser- scanned data plant equipment. The straight pomon pipes, connecting parts, and connection relationship ofthe piping system can be recognized in this algorithm. Normal-based region growing and cylinder surface fitting can extract all possible locations ofpipes, including straight pipes, elbows, and junctions. Tracing the axes of a piping system enables the recognition of the positions of these elements and their connection relationship. Using only point clouds, the recognition algorithm can be performed in a fUlly automatic way. The algorithm was applied to large-scale scamied data of an oil rig and a chemical plant. Recognition rates of about 86%, 88%, and 71% were achieved straight pipes, elbows, andjunctions, respectively.
  • Making a Digital Human Walk Directly in the 3D Laser-scanned Point Clouds of Indoor Environments
    Tsubasa Maruyama, Satoshi Kanai, Hiroaki Date
    Proc. International Conference on Civil and Building Engineering Informatics 69 - 76 2013/11 [Refereed][Not invited]
  • Data Modeling and Geometry Registration for the Integrated Management of the BIM and Laser-scanned Point Clouds
    Shinya Yamaoka, Satoshi Kanai, Hiroaki Date
    Proc. International Conference on Civil and Building Engineering Informatics 55 - 63 2013/11 [Refereed][Not invited]
  • Automatic recognition of piping system from laser scanned point clouds using normal-based region growing
    K. Kawashima, S. Kanai, H. Date
    Proc. of ISPRS Workshop Laser Scanning 2013 2013/11 [Refereed][Not invited]
  • Accurate registration of MMS point clouds of urban areas using trajectory
    S. Takai, H. Date, S. Kanai, Y. Niina, K. Oda, T. Ikeda
    Proc. of ISPRS Workshop Laser Scanning 2013 2013/11 [Refereed][Not invited]
  • Accessibility Evaluation of the as-built two-storey Large-scale Indoor Environments by combining Digital Human Model and Terrestrial Laser Scanners
    Tsubasa Maruyama, Satoshi Kanai, Hiroaki Date
    Proc. 2013 Asian Conference on Design and Digital Engineering HRPC-1-1  2013/08 [Refereed][Not invited]
  • Variational hand modeling based on image-based 3D model reconstruction
    Yulai Xie, Satoshi Kanai, Hiroaki Date
    Proc. 2013 Asian Conference on Design and Digital Engineering EAC-1-2  2013/08 [Refereed][Not invited]
  • As-built modeling of piping system from terrestrial laser scanned point clouds using normal-based region-growing
    Kazuaki Kawashima, Satoshi Kanai, Hiroaki Date
    Proc. 2013 Asian Conference on Design and Digital Engineering EAC-1-3  2013/08 [Refereed][Not invited]
  • Segmentation of MMS Point Clouds of Urban Area Based on Principal Component Analysis
    Hiroaki Date, Teppei mori, Hiroki Yokoyama, Satoshi Kanai, Hiroshi Takeda
    2013 The International Symposium on Mobile Mapping Technology PaperNo.111  2013/04 [Refereed][Not invited]
  • Tomohiro Mizoguchi, Satoshi Kanai, Hiroaki Date, Hiroyuki Tanaka
    Journal of Advanced Mechanical Design, Systems and Manufacturing 7 (5) 862 - 875 1881-3054 2013 [Refereed][Not invited]
     
    Engineering objects often exhibit symmetries on their surfaces for functionality or aesthetics. Detecting such symmetries from their scanned meshes enables advanced applications, such as feature-based CAD model reconstruction or mesh size reduction for efficient CAE. In this paper, we propose a new method for detecting a common class of symmetries in engineering, such as translation, rotation and reflection, from scanned meshes of a variety of objects ranging from mechanical parts to aesthetic products. Major advantages of our proposed method over conventional ones are considerable robustness for scanner noise and exhaustive detection of multiple symmetries from a mesh. We demonstrate its effectiveness from various experiments on scanned meshes acquired by laser or CT scanners. We also show that surface distortions or deformations on the object surfaces can be evaluated using symmetries quantitatively. © 2013 by JSME.
  • Tsubasa Maruyama, Satoshi Kanai, Hiroaki Date
    Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 8026 (2) 366 - 375 0302-9743 2013 [Refereed][Not invited]
     
    Recently, human behavior simulations in 3-dimensional environment models have been enabled by the advance in computer performances. However, manually building the 3D models for the simulations are still costly and time-consuming, and the resultant models are sometimes inaccurate and do not necessarily reflect as-built environments. The final goal of our research is to realize the accessibility evaluation of "as-built" environments based on the human behavior simulation. To achieve the goal, in this study, we developed a technology where as-built 3D environment models could be constructed in a fully automatic way from laser-scanned 3D point clouds measured from as-built indoor environments. Additionally, we realized a basic walking simulation function in the as-built environment model represented by the point clouds. The modeling and simulation efficiency and accuracy were evaluated. © 2013 Springer-Verlag.
  • Yulai Xie, Satoshi Kanai, Hiroaki Date
    Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 8026 (2) 384 - 392 0302-9743 2013 [Refereed][Not invited]
     
    This study proposed a method to construct an anatomy-based variational modeling of a Digital Hand model, which can be used to efficiently generate various individual hand models with different dimensions for virtual ergonomic assessments. The skin surface of a generic hand model was hierarchically partitioned into 15 segments according to the hand surface anatomy. Then it was deformed by scaling and aligning the segments so that it satisfied individual hand dimensions. Moreover, the hand models of different hand postures with markers were reconstructed using a multi-view 3D model reconstruction technique. The extracted positions of markers were used to estimate the individual bone-link structure. The proposed method was validated through comparing the generated hand skin model which fitted the hand dimensions of a subject with his MRI-measured hand surface, and comparing the generated bone-link structure, which fitted joint motion of the subject, with the reconstructed hand models based on a multi-view 3D reconstruction technique. © 2013 Springer-Verlag.
  • Detection and Classification of Pole-like Objects from Mobile Laser Scanning Data of Urban Environments
    Hiroki Yokoyama, Hiroaki Date, Satoshi Kanai, Hiroshi Takeda
    International Journal of CAD/CAM 13 (2) 31 - 40 2013 [Refereed][Not invited]
  • An Efficient Simulation of Skin Contact Deformation for Virtual Ergonomic Assessments of Handheld Products
    Yulai Xie, Satoshi Kanai, Hiroaki Date
    International Journal of CAD/CAM 13 (2) 81 - 95 2013 [Refereed][Not invited]
  • 前濱 宏樹, 伊達 宏昭, 金井 理
    精密工学会学術講演会講演論文集 公益社団法人 精密工学会 2013 845 - 846 2013 
    本研究では，CAEによるパラメータサーベイ効率化を目的とした，段階的ODTスムージングに基づく寸法駆動変形四面体メッシュの品質改善手法を提案してきた．本報では，円錐面や球面，トーラス面等のより多くの種類の曲面のメッシュ品質改善を目的として，法線テンソルに基づく初期表面領域抽出と領域間の幾何学的特性を用いた解析メッシュセグメンテーション手法と，局所パラメータ化による任意曲面のメッシュ品質改善手法を提案する．
  • 関 佳斌, 金井 理, 伊達 宏昭
    精密工学会学術講演会講演論文集 公益社団法人 精密工学会 2013 837 - 838 2013 
    ハンドヘルド情報機器のユーザビリティ評価ができるVirtual prototypeの開発を行うため,小型photo-detectorを用いた爪先色変化による入力イベントの認識機能を開発した．製品上のタッチパネルに対するタップやドラッグ操作をRP造型モデル上で認識するため，本研究では，指先接触時に爪先の色変化をphoto-detectorで検出する．さらに，detector裏面のLED光を二次元画像トラッキングすることにより，指先位置の検出を試みた．
  • Xie Yulai, Kanai Satoshi, Date Hiroaki
    Proceedings of JSPE Semestrial Meeting 公益社団法人 精密工学会 2013 827 - 828 2013 
    A method for variational modeling of individual hands from a template hand model is described. The marked individual hand is reconstructed based on image-based multi-view 3D model reconstruction technique. According to hand joint anatomical knowledge, a single axis rotation assumption is proposed for estimating the joint axes and joint centers by the positions of dot markers at the backside of the hand skin in different hand postures. On the other hand, the skin surface of the template hand model is hierarchically partitioned into segments according to the hand surface anatomy by main creases on palmar side. The segments of the template hand model are scaled according to the feature dimensions of the reconstructed individual hand model. Finally, the template hand model scaled in segment-wise way is registered to the reconstructed hand model by a rough alignment process where the gravity center of the point sets on the creases of both models are matched and a fine alignment process where the segments of both models are matched based on ICP algorithm. Compared with previous works, the method is more subject-friendly, inexpensive, and efficient.
  • 山岡 晋也, 金井 理, 伊達 宏昭
    精密工学会学術講演会講演論文集 公益社団法人 精密工学会 2013 641 - 642 2013 
    本研究では, 急速に普及しているBIMの継続的更新を実現させるため, 建物内をレーザ計測した点群データを用いて変更情報を抽出し, BIMに反映させることを目的とする. 本報では, 変更情報の抽出を可能とするため, RANSACにより計測点群をBIMの構成要素へ自動的に, かつ高速にレジストレーションし, 対応付ける手法を開発した. さらに, BIMへ関連付けられない点を差分点として抽出する手法を提案する.
  • 川島 千明, 金井 理, 伊達 宏昭
    精密工学会学術講演会講演論文集 公益社団法人 精密工学会 2013 637 - 638 2013 
    本研究では，生産設備やプラント施設のレーザ計測点群中から，配管系統を自動的に認識抽出することを目的とする．本報では，法線に基づくregion-growingを用いて配管系統に含まれる直進パイプの認識を行った後，認識された直進パイプの軸線と付近の計測点群を用いて接続要素の認識を行うことで各要素の認識率の高精度化を図った．
  • 畠山 龍, 金井 理, 伊達 宏昭
    精密工学会学術講演会講演論文集 公益社団法人 精密工学会 2013 633 - 634 2013 
    近年，BIMの普及や地上設置型の3Dレーザースキャナの進歩から屋内環境の3次元モデルの利用が容易になってきている．将来的には人の屋内ナビゲーションサービスへの利用などが考えられるが，それには3次元の自己位置推定が必要不可欠である．そこで本研究では3Dレーザースキャナにより得られた詳細な3次元モデルを環境情報として利用し，近年注目されている距離センサであるデプスカメラを用いて3次元の自己位置推定を行い，その精度検証を行った．
  • 丸山 翼, 金井 理, 伊達 宏昭
    精密工学会学術講演会講演論文集 公益社団法人 精密工学会 2013 645 - 646 2013 
    人間行動シミュレーションのための大規模環境モデルの構築は現在人手で行われており，そのコスト，品質，正確さに問題がある．本研究では，実環境の3次元レーザ計測点群を用いて，人間行動シミュレーションに基づく環境のアクセシビリティ評価のための，現状を正確に反映した大規模環境モデルを，低コストに自動構築する技術の開発を目的とする．本報では，前報で開発した歩行シミュレーション機能を，らせん階段を含む2階建ての屋内環境，および凹凸のある坂道を含む，約2億点からなる屋外環境の大規模計測点群上においても人間のモデルが自律的に歩行可能な機能へと拡張したので報告する．
  • Quality Improvement of Finite Element Mesh Models Modified by Mesh Deformation
    Hiroki Maehama, Hiroaki Date, Satoshi Kanai
    Proceedings of the 2012 Asian Conference on Design and Digital Engineering 100064  2012/12 [Refereed][Not invited]
  • Automatic Recognition and Modeling of Piping System from Large-scale Terrestrial Laser Scanned Point Cloud
    Kazuaki Kawashima, Satoshi Kanai, Hiroaki Date, Tae-wan Kim
    Proceedings of the 2012 Asian Conference on Design and Digital Engineering 100022  2012/12 [Refereed][Not invited]
  • Adaptive Selection of Rendering Primitives for Point Clouds of Large Scale Environments
    Takashi Maeno, Hiroaki Date, Satoshi Kanai
    Proceedings of the 2012 Asian Conference on Design and Digital Engineering 100078  2012/12 [Refereed][Not invited]
  • Detection and Classification of Pole-like Objects from Mobile Laser Scanning Data of Urban Environments
    Hiroki Yokoyama, Hiroaki Date, Satoshi Kanai, Hiroshi Takeda
    Proceedings of the 2012 Asian Conference on Design and Digital Engineering 100079  2012/12 [Refereed][Not invited]
  • Constructing a deformable human hand model in contact for virtual ergonomic assessment
    XIE Yulai, KANAI Satoshi, DATE Hiroaki
    Proceedings of the 2012 Asian Conference on Design and Digital Engineering (ACDDE2012) Paper No.100047  2012/12 [Refereed][Not invited]
  • Hiroaki Date, Yusuke Kaneta, Akihiro Hatsukaiwa, Masahiko Onosato, Satoshi Kanai
    Computer-Aided Design and Applications 9 (2) 187 - 197 1686-4360 2012 [Refereed][Not invited]
     
    This paper describes a method of object recognition in terrestrial laser scan data of complex scenes. By local 3D shape matching between the CAD model mesh of the object and the laser scan data of the scene, the existence of the object is recognized and its location and orientation in the scene are extracted. Spin-images are used for shape matching. In this paper, some techniques for applying spin-image matching to the terrestrial laser scan data are proposed. They include robustness improvements for the scan noise and the differences in vertex densities by normal averaging and uniform point sampling, and efficient calculation by using multi-resolution images and geometric point filtering. © 2012 CAD Solutions, LLC.
  • Kazuaki Kawashima, Satoshi Kanai, Hiroaki Date
    EMERGING TECHNOLOGY IN PRECISION ENGINEERING XIV 523-524 932 - 938 1013-9826 2012 [Refereed][Not invited]
     
    In recent years, changes in plant equipment have been becoming more frequent, and as-built modeling of plants from large-scale laser scanned data is expected to make their rebuilding processes more efficient. The purpose of our research was to propose an algorithm which can automatically recognize piping systems from massive terrestrial laser scanned point clouds of plants. Point clouds of a piping system can be extracted based on eigenvalue analysis and using region-growing from the laser scanned points. Eigenvalue analysis of the point clouds and point normals then allows for the recognition of straight portions of pipes. Connecting parts can also be recognized from the connection relationship between pipe axes and their neighboring scanned point distributions.
  • Yulai Xie, Satoshi Kanai, Hiroaki Date
    EMERGING TECHNOLOGY IN PRECISION ENGINEERING XIV 523-524 339 - 344 1013-9826 2012 [Refereed][Not invited]
     
    The contact deformation of human skin is a significant factor in the virtual ergonomic assessment of handheld products, but previous works have neglected it or dealt with it in a simple way. In this paper, we propose a physical model of the contact deformation of human skin and, based on this model, present an efficient contact solving method to simulate the physical contact of the Digital Hand with product surfaces. The realistic contact deformation effect was realized, and we experimentally verified the estimated contact area, contact force and pressure distribution, and found the estimation results by the proposed model and the contact solving method well fit with the experimental data and the past data from the literature.
  • Hiroaki Date, Yusuke Kaneta, Akihiro Hatsukaiwa, Masahiko Onosato, Satoshi Kanai
    Computer-Aided Design and Applications 9 (2) 187 - 197 1686-4360 2012 [Refereed][Not invited]
     
    This paper describes a method of object recognition in terrestrial laser scan data of complex scenes. By local 3D shape matching between the CAD model mesh of the object and the laser scan data of the scene, the existence of the object is recognized and its location and orientation in the scene are extracted. Spin-images are used for shape matching. In this paper, some techniques for applying spin-image matching to the terrestrial laser scan data are proposed. They include robustness improvements for the scan noise and the differences in vertex densities by normal averaging and uniform point sampling, and efficient calculation by using multi-resolution images and geometric point filtering. © 2012 CAD Solutions, LLC.
  • 川島千明, 金井理, 伊達宏昭
    Journal of the Japan Society for Precision Engineering 公益社団法人 精密工学会 78 (8) 722 - 729 0912-0289 2012 [Refereed][Not invited]
     
    Recently, changes of plant equipments become more frequent, and the construction of as-built models of the existing plant from laser scan data is expected to make the reconstruction processes more efficient. The purpose of this research is to propose an algorithm which can recognize a piping system from terrestrial laser scan data of plant equipments. The straight portion of pipes, connecting relationship of the piping system can be recognized in this algorithm. Eigenvalue analyses of the point clouds and of the normal vectors enable the recognition. Using only point clouds, the recognition algorithm can be applied to registered point clouds and can be performed in a fully automatic way. The recognition results of real plants have shown the effectiveness of the algorithm.
  • Xie Yulai, Kanai Satoshi, Date Hiroaki
    Proceedings of JSPE Semestrial Meeting 公益社団法人 精密工学会 2012 271 - 272 2012 
    Hand skin deformation is a significant role in the virtual ergonomic assessment of handheld products. In this paper, a nonlinear elasticity model is used to simulate the skin contact deformation, and quasi volume preserving property of skin is considered for more realistic simulation. An efficient contact solving method is developed for simulating the physical contact with product surfaces. The hand surface skin is partitioned anatomically into different regions for being able to specify different physical properties in them and for efficient simulation for the ergonomic assessment of grasp ability. The realistic contact deformation effect was efficiently realized, and was experimentally verified. The verification results show that the proposed skin deformable model is effective, in the acceptable range for virtual ergonomic assessment.
  • 前野 峻, 伊達 宏昭, 金井 理
    精密工学会学術講演会講演論文集 公益社団法人 精密工学会 2012 301 - 302 2012 
    大規模環境レーザ計測点群の表示は，計測環境の直感的な理解や概観を得るために必要である．しかし，視点が点群に近づいた際，点のみによる表示では面的な情報がないため，計測環境の目視による理解が困難となる．本研究では大規模環境レーザ計測点群の目視による理解を容易にするために，視点からの距離や点分布状況に応じて描画プリミティブ（点，線分，スプラット，メッシュ）を適応的に選択した点群表示手法について述べる．
  • 丸山 翼, 金井 理, 伊達 宏昭
    精密工学会学術講演会講演論文集 公益社団法人 精密工学会 2012 303 - 304 2012 
    近年，大規模環境内における人間行動シミュレーションに関する研究が活発に行われている．しかし，これらのシミュレーション環境の構築は人手で行われており，そのコスト，品質，正確さに問題がある．そこで本研究では，実環境の3次元レーザ計測点群を用いた，現状を正確に反映した低コストな人間行動シミュレーションの実現を目的とする．本報では，屋内環境の計測点群内における人間の歩行シミュレーションについて報告する．
  • 横山 博貴, 伊達 宏昭, 金井 理, 武田 浩志
    精密工学会学術講演会講演論文集 公益社団法人 精密工学会 2012 281 - 282 2012 
    本研究では，設備管理の対象として需要が高い電柱や街灯，標識などの柱状物体を，市街地レーザ計測点群から自動的に認識・分類することを目的としている．これまで柱状物体の認識手法，ならびに電柱，街灯，標識への分類手法を提案してきた．本報では，柱状物体のパーツ構造などの形状特徴，ならびに他の柱状物体との相対的な位置関係から求まるコンテクスト特徴に基づいて，柱状物体の分類精度を改善するアルゴリズムを提案する．
  • 前濱 宏樹, 伊達 宏昭, 金井 理
    精密工学会学術講演会講演論文集 公益社団法人 精密工学会 2012 259 - 260 2012 
    CAEプロセスの効率化を目的とした四面体メッシュの寸法駆動変形手法が提案されている．しかし，変形後の四面体メッシュは要素形状品質が低下し，変形前のメッシュ密度や形状近似精度も失われてしまう．本報ではメッシュ密度や近似精度を考慮した頂点の追加・削除とスムージング手法をシャープエッジから形状表面，形状内部へ段階的に適用することによる，変形後の四面体メッシュの品質改善手法を提案する．
  • 川島 千明, 金井 理, 伊達 宏昭, 金 泰完
    精密工学会学術講演会講演論文集 公益社団法人 精密工学会 2012 279 - 280 2012 
    本研究では，生産設備やプラント施設のレーザ計測点群中から，配管系統を自動的に認識抽出することを目的とする．本報では，グリッド化を用いた前報のアルゴリズムの高速化に加えて，配管系統の軸上の点列への曲線フィッティングによる接続関係の認識と，認識結果に基づくパイプ直進部とエルボ・連結部の3Dモデリングに必要となる定義パラメータ抽出を行ったので報告する．
  • A data management method for efficient search and rendering of multiple large scale point clouds
    T. Maeno, H. Date, S. Kanai
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives 38 (5) 203 - 208 1682-1750 2011/09/03 
    Recently, with the progress of laser scanning technology, it has become possible to scan several environments such as buildings, roads, and cities easily and at a low cost. There are typically three scanning methods: TLS (Terrestrial Laser Scanning), MMS (Mobile Mapping System), and ALS (Airborne Laser Scanning), and the environments are scanned for measurement, modelling, and simulation etc. Therefore, an efficient and comprehensive data management method, which can handle these point clouds in various applications is strongly required. In this paper, we describe a method of data management for efficient search and rendering of multiple large scale point clouds. First, we define a general point cloud file format including the octree and the quantization structure. Next, the data management method enabling an efficient search and rendering of the point clouds is proposed. Finally, the effectiveness of our method is verified using several actual data sets.
  • Pole-like objects recognition from mobile laser scanning data using smoothing and Principal Component Analysis
    H. Yokoyama, H. Date, S. Kanai, H. Takeda
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives 38 (5) 115 - 120 1682-1750 2011/09/03 
    With the spread of the Mobile Laser Scanning (MLS) system, the demands for the management of road and facilities using MLS point clouds have increased. Especially, pole-like objects such as streetlights, utility poles, street signs and etc. are in high demand as facilities to be managed. We propose a method for recognizing pole-like objects from MLS point clouds. Our method is based on Laplacian smoothing using the k-nearest neighbors graph, Principal Component Analysis for recognizing points on pole-like objects, and thresholding for the degree of pole-like objects. Our method can robustly recognize pole-like objects with various radii and tilt angles from MLS point clouds. For correctly segmented objects, accuracy of pole-like object recognition is on average 97.4%.
  • Automatic recognition of a piping system from large-scale terrestrial laser scan data
    K. Kawashima, S. Kanai, H. Date
    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives 38 (5) 283 - 288 1682-1750 2011/09/03 
    Recently, changes in plant equipment have been becoming more frequent because of the short lifetime of the products, and constructing 3D shape models of existing plants (as-built models) from large-scale laser scanned data is expected to make their rebuilding processes more efficient. However, the laser scanned data of the existing plant has massive points, captures tangled objects and includes a large amount of noises, so that the manual reconstruction of a 3D model is very time-consuming and costs a lot. Piping systems especially, account for the greatest proportion of plant equipment. Therefore, the purpose of this research was to propose an algorithm which can automatically recognize a piping system from terrestrial laser scan data of the plant equipment. The straight portion of pipes, connecting parts and connection relationship of the piping system can be recognized in this algorithm. Eigenvalue analysis of the point clouds and of the normal vectors allows for the recognition. Using only point clouds, the recognition algorithm can be applied to registered point clouds and can be performed in a fully automatic way. The preliminary results of the recognition for large-scale scanned data from an oil rig plant have shown the effectiveness of the algorithm.
  • Constructing a Finger Biomechanical Model for Virtual Ergonomic Assessment in Digital Hand
    Yasutomo Shimizu, Hiroaki Date, Satoshi Kanai
    Proceedings of Asian Conference on Design and Digital Engineering 2011 1 543 - 547 2011/08 [Refereed][Not invited]
  • 3D Digital Prototyping of Information Appliances based on Mixed Reality with Markerless Tracking
    Satoshi Kanai, Hiroaki Date, Keita Uchiyama
    Proceedings of Asian Conference on Design and Digital Engineering 2011 1 325 - 328 2011/08 [Refereed][Not invited]
  • Kensuke Sato, Hiroaki Date, Masahiko Onosato
    International Journal on Interactive Design and Manufacturing 5 (2) 133 - 136 1955-2513 2011/06 [Refereed][Not invited]
     
    In this paper, we propose a method for matching, combinations extraction and configuration of mesh models for assembly and geometric modeling. Given two mesh models, a graph is first generated for each model. This graph, called a "feature-graph", represents abstract geometry information and connections of segments (local regions) for the model. Next, a set of pairs of segments which can be matched are extracted by performing sequential matching tests on the graphs. Finally, using the resulting pairs, the configuration between the models is determined by phased registrations keeping previous contact condition. An example of application to assembly modeling is included. © 2011 Springer-Verlag.
  • T. Maeno, H. Date, S. Kanai
    ISPRS WORKSHOP LASER SCANNING 2011 38-5 (W12) 203 - 208 2194-9034 2011 [Refereed][Not invited]
     
    Recently, with the progress of laser scanning technology, it has become possible to scan several environments such as buildings, roads, and cities easily and at a low cost. There are typically three scanning methods: TLS (Terrestrial Laser Scanning), MMS (Mobile Mapping System), and ALS (Airborne Laser Scanning), and the environments are scanned for measurement, modelling, and simulation etc. Therefore, an efficient and comprehensive data management method, which can handle these point clouds in various applications is strongly required. In this paper, we describe a method of data management for efficient search and rendering of multiple large scale point clouds. First, we define a general point cloud file format including the octree and the quantization structure. Next, the data management method enabling an efficient search and rendering of the point clouds is proposed. Finally, the effectiveness of our method is verified using several actual data sets.
  • H. Yokoyama, H. Date, S. Kanai, H. Takeda
    ISPRS WORKSHOP LASER SCANNING 2011 38-5 (W12) 115 - 120 2194-9034 2011 [Refereed][Not invited]
     
    With the spread of the Mobile Laser Scanning (MLS) system, the demands for the management of road and facilities using MLS point clouds have increased. Especially, pole-like objects such as streetlights, utility poles, street signs and etc. are in high demand as facilities to be managed. We propose a method for recognizing pole-like objects from MLS point clouds. Our method is based on Laplacian smoothing using the k-nearest neighbors graph, Principal Component Analysis for recognizing points on pole-like objects, and thresholding for the degree of pole-like objects. Our method can robustly recognize pole-like objects with various radii and tilt angles from MLS point clouds. For correctly segmented objects, accuracy of pole-like object recognition is on average 97.4%.
  • K. Kawashima, S. Kanai, H. Date
    ISPRS WORKSHOP LASER SCANNING 2011 38-5 (W12) 283 - 288 2194-9034 2011 [Refereed][Not invited]
     
    Recently, changes in plant equipment have been becoming more frequent because of the short lifetime of the products, and constructing 3D shape models of existing plants (as-built models) from large-scale laser scanned data is expected to make their rebuilding processes more efficient. However, the laser scanned data of the existing plant has massive points, captures tangled objects and includes a large amount of noises, so that the manual reconstruction of a 3D model is very time-consuming and costs a lot. Piping systems especially, account for the greatest proportion of plant equipment. Therefore, the purpose of this research was to propose an algorithm which can automatically recognize a piping system from terrestrial laser scan data of the plant equipment. The straight portion of pipes, connecting parts and connection relationship of the piping system can be recognized in this algorithm. Eigenvalue analysis of the point clouds and of the normal vectors allows for the recognition. Using only point clouds, the recognition algorithm can be applied to registered point clouds and can be performed in a fully automatic way. The preliminary results of the recognition for large-scale scanned data from an oil rig plant have shown the effectiveness of the algorithm.
  • Yokoyama Hiroki, Date Hiroaki, Kanai Satoshi, Takeda Hiroshi
    Proceedings of JSPE Semestrial Meeting 公益社団法人 精密工学会 2011 143 - 144 2011 
    モバイルレーザスキャニング(MLS)の普及により，市街地レーザ計測点群を用いた道路やその周辺設備の管理への需要が増加している．特に，電柱や街灯，標識などの柱状物体は，管理対象の設備として需要が高い．そこで本研究では，市街地レーザ計測点群に対して細線化と主成分分析，並びに柱状物体度評価指標を用いて，様々な太さや傾きの柱状物体を自動的に認識できるアルゴリズムを開発し，その認識性能を評価したので報告する．
  • Kaneta Yusuke, Date Hiroaki, Kanai Satoshi
    Proceedings of JSPE Semestrial Meeting 公益社団法人 精密工学会 2011 127 - 128 2011 
    本研究では，環境内における認識したい対象の存在有無・位置姿勢を，対象の形状モデルを用いて環境のレーザ計測データ（三角形メッシュ）から認識する手法を提案してきた．本報告では，レジストレーションされた計測点群への対象認識の柔軟な適用，ならびに大規模計測データでの対象認識実現のためのデータ量を削減した，三角形メッシュを用いない，レーザ計測点群に対する対象認識手法を提案する．
  • Kawashima Kazuaki, Kanai Satoshi, Date Hiroaki
    Proceedings of JSPE Semestrial Meeting 公益社団法人 精密工学会 2011 123 - 124 2011 
    近年，レーザ計測点群を利用した，既存プラント設備の実態が反映されたas-built型モデル作成の需要が高まっている．特に，配管系統はプラント設備のモデル化で必須の対象となる．本報では，共分散行列を用いた計測点群全体からの配管系統の計測点群の自動抽出，および，認識した各パイプの径，軸位置・方向に基づくエルボやＴジャンクションといった接続要素とパイプ間の接続関係の自動認識を行ったので報告する．
  • Ui Koutarou, Kanai Satoshi, Date Hiroaki, Yokoo Yasuhiro, Asada Norichika, Takeda Hiroshi
    Proceedings of JSPE Semestrial Meeting 公益社団法人 精密工学会 2011 129 - 130 2011 
    本研究では3次元都市モデリングおよび2次元マッピングのための，航空機LiDARデータからの建物領域の認識を目的としている．本報では，地表面および建物領域認識の高精度化のための，モルフォロジーフィルターを用いた地表面分類と、非地面点領域の境界線形状に基づく建物領域の判定手法を提案し，その分類精度を検証する．
  • Nagafuchi Tatsuya, Kanai Satoshi, Date Hiroaki
    Proceedings of JSPE Semestrial Meeting 公益社団法人 精密工学会 2011 275 - 276 2011 
    近年，情報機器開発に際しユーザビリティを考慮したUI設計が求められている．本研究では，これまでユーザーの注視点位置を推定するEye-Trackingシステムの開発と精度の向上を行なってきた．これを用いてUI可動型ディジタルプロトタイプ操作時にユーザーが注視しているUI上の注視オブジェクトの特定を行うことで，誤操作時のUI上の箇所や誤操作原因が推定可能となる．そこで本報告では，Eye-Trackingを用いたディジタルプロトタイプ上注視オブジェクトの特定について報告する．
  • Xie Yulai, Kanai Satoshi, Date Hiroaki
    Proceedings of JSPE Semestrial Meeting 公益社団法人 精密工学会 2011 273 - 274 2011 
    The virtual ergonomic assessment based on Digital Hand which estimates grasp posture and evaluates the quality of grasp is valuable for hand-held product design, because it can save the cost of test subjects, time, fabricating physical mockups, and it also enables objective evaluation. In this paper, we propose the method to implement deformable property caused by a contact between Digital Hand and the product surface by modeling the fingers as ″quasi-rigid″ objects, by constructing a physical model based on Boussinesq formula which approximates skin contact deformation mechanism, by detecting collision between Digital Hand and a product surface and enlarging the collision area, and then by finally solving Linear Complementarity Problem to resolve the contact and to produce the visible skin surface deformation. The plausible skin deformation could be obtained, because the method preserved the volume of Digital Hand before and after the skin deformation. In addition, utilizing the locality property of the deformation, the method can be easily used by the existing Digital Hand model and do not affect its original scheme of skin deformation caused by bending the finger.
  • Efficient Cutaway Model Generation for Interactive Cutaway Viewing system
    Hiroaki Date, Hiromu Furukawa, Masahiko Onosato
    Proceedings of IDMME - Virtual Concept 2010 2010/10 [Refereed][Not invited]
  • Dimension-driven Deformation and Untangling of Tetrahedral Meshes
    Yuki Takano, Hiroaki Date, Masahiko Onosato
    Proceedings of 2010 Asian Conference on Design and Digital Engineering 483 - 491 2010/08 [Refereed][Not invited]
  • KANAI Satoshi, MASUDA Hiroshi, ONOSATO Masahiko, KAWAMURA Kohji, DATE Hiroaki
    Journal of the Japan Society for Precision Engineering 公益社団法人 精密工学会 76 (10) 1121 - 1124 0912-0289 2010 [Not refereed][Not invited]
  • Hiroaki Date, So Noguchi, Masahiko Onosato, Satoshi Kanai
    IEEE TRANSACTIONS ON MAGNETICS 45 (3) 1352 - 1355 0018-9464 2009/03 [Refereed][Not invited]
     
    This paper describes a method for flexibly controlling the properties of a given multimaterial tetrahedral mesh for finite-element analysis. Our method is based on multiresolution techniques. A given mesh is first subdivided and then simplified so that the resulting mesh satisfies the user-specified thresholds for mesh properties (element size, shape, valence, and geometric tolerance). Once the simplification is completed, mesh resolution and density can be modified quickly by using level of detail.
  • DATE Hiroaki
    Journal of the Japan Society of Precision Engineering 公益社団法人精密工学会 74 (12) 1264 - 1268 0912-0289 2008/12/05 [Not refereed][Not invited]
  • MIZOGUCHI Tomohiro, DATE Hiroaki, KANAI Satoshi
    Journal of the Japan Society of Precision Engineering 公益社団法人精密工学会 74 (7) 752 - 759 0912-0289 2008/07 [Refereed][Not invited]
     
    To effectively use scanned meshes obtained by 3D laser scanner or X-ray CT scanning systems in engineering applications, such as inspection and CAD model reconstruction, we need to segment meshes and extract desirable regions and their approximating surfaces. Surfaces of engineering objects are commonly represented by a set of analytic surfaces, such as planes, cylinders, spheres, cones. Therefore, the mesh surface of them needs to be approximated by a set of analytic surfaces. In this paper we propose an efficient mesh segmentation algorithm based on region growing and region merging. Our ...
  • 小野里 雅彦, 増田 寿信, 毛利 健二, 伊達 宏昭, 田中 文基
    図学研究 日本図学会 42 (1) 45 - 48 0387-5512 2008 
    大地震等で倒壊した家屋から被災者を救助するためのレスキュー機器の研究開発が重要な課題となっている.しかしながら救助の場であるがれきに対する学術的知見が不足しており, がれきに対する研究が求められている.本研究グループでは工学的アプローチのひとつとして, がれきの形態解析をこれまで行っており, 本報告では, 物理シミュレータを用いて形成した模擬的ながれきのモデルを対象に, がれきの定量的なパラメータの分類と, がれきの形成する内部空間の構造を離散ボロノイ分割に基づき分析する手法の提案を行っている.これによりがれきの内部自由空間は分散する局所最大空球とそれらを結ぶネットワークにより特徴付けられることを示した.こうした空間の構造分析手法によりレスキューロボット等の開発に必要となる内部自由空間に関する特徴量を得ることが可能となった.
  • Hiroaki Date, Masahiko Onosato
    Computer-Aided Design and Applications 5 (1-4) 287 - 295 1686-4360 2008 [Refereed][Not invited]
     
    In this paper, we propose a triangular mesh deformation method based on dimensions. By specifying the type of dimensions, the regions defining the dimensions, and the target dimensions, the mesh is automatically deformed so that it satisfies the target dimensions. Mesh deformation is based on space-based deformation using barycentric coordinates. The deformation handle, which consists of a set of triangular prisms, is automatically created by mesh segmentation, simplification and offsetting of simplified mesh. In deformation, the deformation and fixed spaces are assigned to each prism in the handle, and the mesh is deformed by applying affine transformation to the control vertices and space-based deformation to the deformation space. Results for the mechanical parts show the effectiveness of our method. © 2008 CAD Solutions, LLC.
  • Masahiko Onosato, Fumiki Tanaka, Hiroaki Date, Ryoji Kawagishi
    MANUFACTURING SYSTEMS AND TECHNOLOGIES FOR THE NEW FRONTIER 107 - 110 2008 [Refereed][Not invited]
     
    Manufacturing in the digital age is deeply dependent on the information and communication technologies (ICT) and the manufacturing activities have been changing from direct operations by human operators to digital data exchanges by computers. It is fairly difficult for engineers and workers to understand the entire image of digital manufacturing activities. A concept of complex manufacturing space (CMS) introduces the duality of the physical world and the information world to manufacturing design, planning, control, and other activities. This paper explains the complex manufacturing space concept and some technical challenges for its implementation.
  • Tomohiro Mizoguchi, Hiroaki Date, Satoshi Kanai, Takeshi Kishinami
    PROCEEDINGS OF THE ASME INTERNATIONAL DESIGN ENGINEERING TECHNICAL CONFERENCES AND COMPUTERS AND INFORMATION IN ENGINEERING CONFERENCE 2007, VOL 6, PTS A AND B 547 - 556 2008 [Refereed][Not invited]
     
    Recently meshes of engineering objects are easily acquired by 3D laser or high energy X-ray CT scanning systems, and these meshes are widely used in product developments. To effectively use scanned meshes in engineering applications, such as inspection, CAD model reconstruction, and convergent-type CAE, we need to segment meshes and extract desirable regions and their approximating surfaces as preprocessing. Engineering objects are commonly represented as a set of analytic surfaces, such as planes, cylinders, spheres, cones, and tori. Therefore, the mesh surface of engineering objects needs to be approximated as a set of analytic surfaces. Moreover, a mesh surface should be approximated with a minimum number of analytic surfaces and their approximating error should be minimized as a result of segmentation. We call the segmentation that satisfies these two conditions the optimal segmentation as proposed in [1]. However, optimal segmentation algorithms need a long calculation time. Today's high energy X-ray CT scanning systems generate large meshes with millions of triangles from objects including hundreds of regions. Thus, computationally expensive algorithms, such as [1], cannot be directly applied to these large and complex meshes from the aspect of efficiency. In this paper we propose an efficient new quasi-optimal mesh segmentation algorithm via region growing and region merging. First, our algorithm robustly and accurately estimates mesh principal curvatures using the local surface fitting by two-pass algorithm. Second, it uses the curvatures to appropriately create seed regions, and then it quickly grows each seed region and extracts grown regions and their approximating analytic surfaces from a whole mesh. Finally, our region merging algorithm efficiently merges extracted regions in order to minimize the number of regions while keeping the user specified tolerances of the surface fitting, and it results in quasi-optimal segmentation. We demonstrate the performance of our algorithm with scanned meshes acquired from real engineering objects by 3D laser and X-ray CT scanning systems.
  • Matsuda, Takuya, Tanaka, Fumiki, Onosato, Masahiko, Date, Hiroaki
    Journal of Advanced Mechanical Design Systems and Manufacturing 一般社団法人 日本機械学会 2 (4) 597 - 608 2008 [Not refereed][Not invited]
     
    In a machining system using computer numerical control (CNC) machine tools, detailed models of machining information are necessary to simulate detailed machining and to control the complex motion of machine tools. However, existing machining information models lack the necessary information and are described in their own formats. Consequently, many models which include the same information exist. Moreover various simulations for a virtual machining system and adaptive control for a real machining system are inacculate. To solve these problems, a digital machining information (DMI) model to support a real-virtual machining system is proposed in this study.
  • MIZUNO Gaku, DATE Hiroaki, KANAI Satoshi, KISHINAMI Takeshi
    Journal of the Japan Society of Precision Engineering 公益社団法人精密工学会 73 (3) 383 - 388 0912-0289 2007/03 [Refereed][Not invited]
     
    In this paper, we present a parametric deformation method for mesh models based on barycentric coordinates for convex polytope. First, we propose a FFD (free-form deformation)based on barycentric coordinates. Arbitrary convex polytope can be used for the deformation handle of the FFD. Next, we propose an automatic handle construction method for the FFD based on definition and classification of deformation types. Deformation handles suitable for user intended deformation types can be automatically constructed by selecting the deformation type and model portions to be deformed. Finally, we pr...
  • ONOSATO Masahiko, TANAKA Fumiki, DATE Hiroaki
    Proceedings of JSPE Semestrial Meeting 一般社団法人日本機械学会 2007 949 - 950 2007 
    Manufacturing in the digital age is deeply dependent on the information and communication technologies (ICT) and the manufacturing activities have been changing from direct operations by human operators to digital data exchanges by computers. It is fairly difficult for engineers and workers to understand the entire image of digital manufacturing activities in an intuitive way. The author proposes a concept of a complex manufacturing space with which various concepts in both real and virtual manufacturing are associated in an integrated conceptual scheme. The complex manufacturing space is an analogy of complex numbers in mathematics and it introduces the duality of the physical world and the information world to manufacturing design, planning, control, and other activities. This paper introduces the complex manufacturing concept and some technical challenges for its implementation.
  • DATE Hiroaki, KANAI Satoshi
    Journal of Japan Society for Design Engineering 日本設計工学会 41 (2) 68 - 76 0919-2948 2006/02/05 [Not refereed][Not invited]
  • A parametric deformation for mesh models based on barycentric coordinates
    Gaku Mizuno, Hiroaki Date, Satoshi Kanai, Takeshi Kishinami
    Proceedings of the 6th IASTED International Conference on Visualization, Imaging, and Image Processing, VIIP 2006 359 - 364 2006 
    Free-Form Deformation (FFD) [1] is a popular method for deforming 3D geometric models. FFD first embeds the model in the regular lattice (handle). Then by deforming the handle, the embedded model is deformed. However, FFD has the following problems for engineering applications: 1) it is difficult to make the handle suitable for the user-intended deformation type such as bend and twist, 2) it requires complicated manipulation, and 3) it cannot produce deformations precisely because the degree of deformation such as the angle of bend cannot be specified explicitly. Therefore, in order to solve these problems, we propose a parametric deformation method for mesh models. First, we propose an FFD based on barycentric coordinates (BCFFD) for a convex polytope. Second, we propose an automatic handle construction method for the BCFFD based on definition and classification of deformation types such as bend, twist, and so on. Third, we propose a parametric deformation method based on BCFFD. Finally, we derive constraints for the handle that preserve geometric continuity at boundary between the deformed and non-deformed portion of the model. Using our methods, the user can deform the mesh model by selecting the deformation type and portions to be deformed, and by manipulating deformation parameters.
  • Flexible feature and resolution control of triangular meshes
    Hiroaki Date, Satoshi Kanai, Takeshi Kishinami, Ichiro Nishigaki
    Proceedings of the 6th IASTED International Conference on Visualization, Imaging, and Image Processing, VIIP 2006 319 - 324 2006 
    In this paper, we propose a new feature and resolution control method of triangular meshes to realize efficient mesh uses. The basic approach of our method is to commence the production of mesh with different degrees of feature suppression and resolution from feature-removed coarse mesh by LOD technique. First, the features of the input mesh are automatically recognized using a mesh segmentation technique, and all recognized features are removed. As a result, the input mesh is decomposed into a feature-removed mesh and some feature meshes. Then, mesh simplification by edge collapse is applied to the feature-removed mesh and feature meshes. Finally, arbitrary resolution and feature-suppressed mesh can be obtained quickly by feature recovering and LOD. The effectiveness of our approach is shown through some examples and applications.
  • Date Hiroaki, Kanai Satoshi, Nishigaki Ichiro, Onosato Masahiko
    Proceedings of JSPE Semestrial Meeting 一般社団法人日本機械学会 2006 41 - 42 2006 
    Connecting some meshes is required for realizing mesh-based efficient CAE, for example, generating assembly models or setting analysis conditions. This paper proposes a new mesh combining method for triangular and tetrahedral meshes. First, the connectors which connect given two meshes are inserted, and then they are removed by the edge collapse simplification. As a result, a connected mesh that has coincident elements on the shared portions can be obtained. Our method is applicable to the meshes that have no-coincident elements and geometries on the portion to be connected, and it supports several types of mesh connections, i.e. curve-curve, curve-surface, and surface-surface connections.
  • Tomohiro Mizoguchi, Hiroaki Date, Satoshi Kanai, Takeshi Kishinami
    GEOMETRIC MODELING AND PROCESSING - GMP 2006, PROCEEDINGS 4077 644 - 654 0302-9743 2006 [Refereed][Not invited]
     
    For effective application of laser or X-ray CT scanned mesh models in design, analysis, and inspection etc, it is preferable that they are segmented into desirable regions as a pre-processing. Engineering parts are commonly covered with analytic surfaces, such as planes, cylinders, spheres, cones, and tori. Therefore, the portions of the part's boundary where each can be represented by a type of analytic surface have to be extracted as regions from the mesh model. In this paper, we propose a new mesh segmentation method for this purpose. We use the mesh curvature estimation with sharp edge recognition, and the non-iterative region growing to extract the regions. The proposed mesh curvature estimation is robust for measurement noise. Moreover, our proposed region growing enables to find more accurate boundaries of underlying surfaces, and to classify extracted analytic surfaces into higher-level classes of surfaces: fillet surface, linear extrusion surface and surface of revolution than those in the existing methods.
  • Hiroaki Date, Satoshi Kanai, Takeshi Kishinami, Ichiro Nishigaki
    2006 SICE-ICASE INTERNATIONAL JOINT CONFERENCE, VOLS 1-13 3685 - + 2006 [Refereed][Not invited]
     
    With the progress of 3D scanning technology and storing mesh data to 3D model databases, the use of the meshes obtained by scanning and DB querying in CAE have been strongly required in addition to those obtained from traditional meshing of solid models. In our research, we developed a multiresolution mesh processing system for triangular meshes to realize CAE using various kinds of meshes. Our system consists of three functions based on the multiresolution techniques: mesh quality improvement, mesh properties control, and local mesh density control. This paper describes these functions including the extension for tetrahedral meshes, and also shows their effective use in the CAE.
  • Gaku Mizuno, Hiroaki Date, Satoshi Kanai, Takeshi Kishinami, Masahiko Onosato
    2006 SICE-ICASE INTERNATIONAL JOINT CONFERENCE, VOLS 1-13 3697 - + 2006 [Refereed][Not invited]
     
    Free-Form Deformation (FFD) is a popular method for deforming 3D geometric models. FFD first embeds the model in the parametric space defined by regular lattice (handle). Then by deforming the handle, the embedded model is deformed. However the FFD has following problems for engineering applications such as deformation of mesh models for Computer Aided Engineering (CAE): 1) It is difficult to make handle suitable for intended deformation type such as bend and twist, 2) it requires complicated manipulation to deform and 3) it can not explicitly specify the degree of deformations such as angle of bend. Therefore, in order to solve these problems, we present a parametric deformation method for mesh models. First, we propose an FFD based on barycentric coordinates (BCFFD). Then, we propose an automatic handle construction method for the BCFFD based on definition and classification of deformation types such as bend, twist and so on. Finally, we propose a parametric deformation method. Using our methods, the user can deform the mesh model by selecting deformation type and portions to be deformed, and by manipulating one or two deformation parameters.
  • MIZOGUCHI TOMOHIRO, DATE HIROAKI, KANAI SATOSHI, KISHINAMI TAKESHI
    Transactions of Information Processing Society of Japan 一般社団法人情報処理学会 46 (12) 3175 - 3187 0387-5806 2005/12/15 [Not refereed][Not invited]
     
    Recently, mesh models are easily obtained from several resources such as reverse engineering and searching 3D database. These mesh models are often used at the style design stage in product development. But at the detail design stage, solid models are necessary, therefore the technique which automatically generates solid models from mesh models is required for more efficient product development. In this paper, we propose a new method of feature edges extraction of triangular mesh models based on wide range normal evaluation and segmentation using modified Watershed method for generating sol...
  • H Date, S Kanai, T Kishinami, Nishigaki, I, T Dohi
    JOURNAL OF COMPUTING AND INFORMATION SCIENCE IN ENGINEERING 5 (4) 266 - 276 1530-9827 2005/12 [Refereed][Not invited]
     
    In this paper, we propose a new triangular finite element mesh generation scheme from various kinds of triangular meshes using the multiresolution technique. The proposed scheme consists of two methods: a mesh quality improvement method and a mesh property control method. The basic strategy of these methods is a combination of the mesh subdivision and simplification. Given mesh is first subdivided to obtain enough degree of freedom for a property change, then by simplification using edge collapse for the resulting mesh to change the mesh properties, we can easily improve and control the mesh properties required for finite element analysis.
  • ENDO Yui, DATE Hiroaki, KANAI Satoshi, KISHINAMI Takeshi
    Journal of the Japan Society for Precision Engineering. Supplement. Contributed papers 公益社団法人精密工学会 71 (9) 1168 - 1172 1348-8724 2005/09/05 [Not refereed][Not invited]
     
    This paper proposes a new algorithm for fitting a Loop subdivision surface to dense sample points. Our fitting algorithm uses marching cubes and shrink-wrapping to fit the initial control mesh to the points measured from objects. It uses quasi-interpolation to quickly calculate the positions of initial control points from subdivision limit points and uses QEM- and curvature-based mesh simplification to preserve feature boundaries of the minute fillet regions so as to accurately fit to the feature edges. The effectiveness of our fitting algorithm was verified in reverse engineering of broad ...
  • Date Hiroaki, Kanai Satoshi, Kishinami Takeshi, Iwakoshi Mutsuro, Kobayashi Masayoshi
    IPSJ SIG Notes 一般社団法人情報処理学会 2005 (44) 55 - 60 0919-6072 2005/05 [Refereed][Not invited]
     
    In this paper, we introduce a design system of textured shapes with small bumps using mesh-modeling techniques. Our system consists of three functions: 1) texture mesh data acquisition based on 3D scanning of sample texture material and texture extraction from existing textured models, 2) digital data processing of the texture mesh, and 3) textured shape modeling by combining meshes according to the user-specified region or direction of texture. These functions allow us to achieve effective textured shape design and prototyping.
  • Shimizu Takafumi, Date Hiroaki, Kanai Satoshi, Kishinami Takeshi
    IPSJ SIG Notes 一般社団法人情報処理学会 2005 (44) 7 - 12 0919-6072 2005/05 [Refereed][Not invited]
     
    In this paper, we propose a mesh smoothing method with feature edge identification for mesh models including the measurement noise obtained from 3D scanner. First, by doing the eigen analysis of normal voting tensor, mesh edge groups that compose the feature edges can be extracted. Second, a bilateral filtering is applied to the extracted mesh edge groups in order to generate smooth edges along feature edge directions. Finally, by applying modified bilateral filtering to the overall mesh, the mesh model is obtained where the feature edges are smoothed along their directions and measurement noise included in faces surrounded by feature edges are removed.
  • DATE Hiroaki, KANAI Satoshi, KISHINAMI Takeshi, NISHIGAKI Ichiro, DOHI Takayuki
    Journal of the Japan Society for Precision Engineering. Supplement. Contributed papers 公益社団法人精密工学会 71 (2) 223 - 227 1348-8724 2005/02/05 [Not refereed][Not invited]
     
    Low-quality triangular meshes with extremely distorted triangles are generated from several mesh generation approaches, including reverse engineering and solid model tessellations. However, such meshes have a negative effect on mesh applications such as digital geometry processing and finite element analysis. Therefore, a robust and fast algorithm for mesh quality improvement is strongly required. In this paper, we propose a new mesh quality improvement method based on mesh subdivision and simplification. In our method, we first subdivide the input mesh until the resulting mesh has a suffic...
  • H Date, S Kanai, T Kishinami, Nishigaki, I
    NINTH INTERNATIONAL CONFERENCE ON COMPUTER AIDED DESIGN AND COMPUTER GRAPHICS, PROCEEDINGS 339 - 344 2005 [Refereed][Not invited]
     
    In this paper, we propose a new triangular finite element mesh generation method based on simplification of high-density mesh and adaptive Level-of-Detail (LOD) methods for efficient CAE. Mesh simplification evaluating mesh properties is applied to control the mesh properties required for FE mesh, such as the number of triangular elements, element shape quality and size while keeping the specified approximation tolerance. Adaptive LOD methods based on vertex hierarchy according to curvature and region of interest, and global LOD method preserving density distributions are also proposed in order to construct a more appropriate FE mesh. These methods enable efficient generation of FE meshes with appropriate properties for analysis from a high-density mesh. Finally, the effectiveness of our approach is shown through evaluations of the FE meshes for practical use.
  • H Date, S Kanai, T Kisinami
    APPLICATIONS OF DIGITAL TECHNIQUES IN INDUSTRIAL DESIGN ENGINEERING-CAID&CD' 2005 146 - 151 2005 [Refereed][Not invited]
     
    In this paper, we propose a new texture extraction method from an existing mesh surface with texture consisting of small bumps for efficient textured shape design. Our texture extraction approach consists of two stages: In the first stage, the geometries of base surface and texture (displacements) are separated from the textured surface using a combination of smoothing operations: the normal smoothing for estimating base surface normals, and the smoothing of vertex positions for separating geometries. The latter one is realized by moving vertices along the estimated normal direction, and it enables extraction of displacements from meshes with different proper-ties. In the second stage, by applying mesh flattening using a parameterization technique to the estimated base surface, the initial flat mesh is generated. The final texture is then obtained by offsetting the vertices of the resulting flat mesh according to the extracted displacements. As a result, texture mesh, which represents bumpiness of the texture from base surface by the height values of the vertices, can be obtained.
  • T Mizoguchi, H Date, S Kanai, T Kishinami
    PROCEEDINGS OF THE 8TH JOINT CONFERENCE ON INFORMATION SCIENCES, VOLS 1-3 1610 - 1613 2005 [Refereed][Not invited]
     
    Recently, a technique which automatically generates solid models from mesh models is required in the field of reverse engineering for more efficient product development. In this paper, we propose a new feature edge extraction method from triangular mesh models based on wide range normal evaluation and segmentation using the modified Watershed method. Our feature edge extraction method is robust for mesh models with scanning noise and different mesh connectivity, and it enables recognition of the region bounded by extracted feature edges as a face. It also enables extraction of boundary edges of the fillet surface as feature edges, which was difficult using previous methods. These characteristics are effective for automatic solid model generation. Moreover we implemented functions for selecting and collecting the required feature edges extracted at different parameter settings, and transferring the resulting feature edges into a 3D CAD system.
  • T Shimizu, H Date, S Kanai, T Kishinami
    NINTH INTERNATIONAL CONFERENCE ON COMPUTER AIDED DESIGN AND COMPUTER GRAPHICS, PROCEEDINGS 1 (1) 281 - 286 2005 [Refereed][Not invited]
     
    In this paper, we propose a new mesh smoothing method for mesh models with measurement noise obtained from a 3D scanner. Our proposed method enables not only the removal of noise from the faces but the preservation and smoothing of features recognized as sharp edges and corners. First, by using the eigen analysis of normal voting tensor, mesh edges composed of sharp edges can be extracted. Second, bilateral filtering is applied to extracted mesh edges to smooth the mesh edges along the direction of the sharp edge. Finally, by applying modified bilateral filtering to the overall mesh, a mesh model with sharp edges smoothed along their directions and measurement noise removed from faces was obtained.
  • Real -time tracking of head rotation for human-computer-interaction based on image projection curves
    Takanori Yamada, Katsuhisa Shibukawa, Hiroaki Date, Satoshi Kanai, Takeshi Kishinami
    Proceedings of the Fourth IASTED International Conference on Visualization, Imaging, and Image Processing 129 - 134 2004 
    This paper addresses our proposed method to automatically detect the direction of the rotational motion of the human head The method introduced in this paper develops a human interface, especially in regards to the mouse cursor which can be controlled by the motion of the head motion. Conventionally, template matching is mainly used to make a computer recognize the motion and position of the human face, but there are several problems with terms of versatility and time involved with calculation. We propose a new algorithm to detect the head rotational motion by calculating the shift length of projection curves which are derived from the Hue information of each image.
  • DATE Hiroaki, KANAI Satoshi, KISHITANI Takeshi
    Journal of the Japan Society of Precision Engineering 公益社団法人精密工学会 69 (4) 581 - 585 0912-0289 2003/04/05 [Not refereed][Not invited]
     
    The surface of many industrial products may have geometries composed both of base shape and surface detail. From the design point of view, it is efficient to design the base shape and surface detail independently, and then to integrate the surface detail with the base shape surface for obtaining the surface-detail-integrated shape. In this paper, to realize a flexible and efficient mesh modeling for the surface-detail-integrated shape, we propose a method that integrates the surface detail with the base shape using parameterization. In our method, the user can simply design the surface-deta...
  • KANAI Satoshi, DATE Hiroaki, KISHINAMI Takeshi
    Journal of the Japan Society of Precision Engineering 公益社団法人精密工学会 69 (4) 490 - 493 0912-0289 2003/04/05 [Not refereed][Not invited]
  • H Date, S Kanai, T Kishinami
    IGARSS 2001: SCANNING THE PRESENT AND RESOLVING THE FUTURE, VOLS 1-7, PROCEEDINGS 1847 - 1849 2001 [Refereed][Not invited]
     
    In this paper, we propose an adaptive level-of-detail control method using wavelet-based multiresolution representation for triangulated mesh and digital image for the purpose of efficient data processing for transmitting and displaying a textured digital terrain model in a network-based server-client system.
  • DATE Hiroaki, KANAI Satoshi, KISHINAMI Takeshi
    Journal of the Japan Society of Precision Engineering 公益社団法人精密工学会 65 (9) 1275 - 1279 0912-0289 1999/09/05 [Not refereed][Not invited]
     
    Recently, muchi, interest is being taken in method to protect the copyright of digital data and preventing illegal duplication of it. However, in the area of CAD/CAM and CG, there are no effective ways to protect the copyright of the 3D geometric models. As a first step to solve the problem, a new digital watermarking method for 3D polygonal models is introduced in this paper. Watermarking is one of the copyright protection methods where an invisible watermark is secretly embedded into the original data. The proposed watermarking method is based on the wavelet transform (WT) for the polygon...
  • Hiroaki Date, Satoshi Kanai, Takeshi Kishinami
    Proceedings of the ASME Design Engineering Technical Conference 2 1063 - 1072 1999 
    Recently, much interest is being taken in a method to protect the copyright of digital data and prevent illegal duplication of it. However, in the area of CAD/CAM and CG, there are no effective ways to protect the copyright of the 3D geometric models. As a first step to solve this problem, a new digital watermarking method for 3D polygonal'models is introduced in this paper. Watermarking is one of the copyright protection methods where an invisible watermark is secretly embedded into the original data. The proposed wateimarking method is based on the wavelet transform (WT) and multi-resolution representation(MRR) of the polygonal model. The watermark can be embedded in the large wavelet coefficient vectors at various resolution levels of the MRR. This makes the embedded watermark imperceptible and invariant to the affine transformation,- and also makes the control of the geometric error caused by the watermarking reliable.

MISC

Presentations

  • 点群処理の基礎~近傍探索，主成分分析，領域抽出，位置合せ~  [Invited]
    伊達宏昭
    点群処理基礎技術講習会  2022/11
  • Quality LiDAR Point Cloud Acquisition and Modeling of Large-Scale Environments  [Invited]
    Hiroaki Date
    2022 Frontier Measurements Workshop  2022/10
  • 点群処理の基礎  [Invited]
    伊達宏昭
    点群処理基礎技術講習会  2021/11
  • 計測品質を考慮したTLS点群の取得と処理  [Invited]
    伊達宏昭
    3Dレーザスキャニング＆イメージングシンポジウム2021  2021/11
  • 設備や環境の高品質計測点群取得と自動モデル化技術  [Invited]
    伊達宏昭
    The 27th Symposium on Sensing via Image Information  2021/06
  • 点群処理の基礎〜近傍探索，特徴・領域抽出，位置合せ〜  [Invited]
    伊達 宏昭
    点群処理基礎技術講習会  2019/09
  • High-quality 3D Scan Data Generation using Multiple Scanning Systems  [Invited]
    Hiroaki Date
    The 5th International Symposium toward the Future of Advanced Researches in Shizuoka University 2019  2019/03
  • 点群処理の基礎  [Invited]
    伊達 宏昭
    点群処理基礎技術講習会  2018/09
  • High-Quality 3D Scan Data Generation using Multiple Scanning Systems  [Not invited]
    Hiroaki Date
    East Asia Innovation Accelerator Forum, The 1st Korea-China-Japan Joint Symposium 2018  2018/08
  • 点群処理の基礎  [Invited]
    伊達宏昭
    点群処理基礎技術講習会  2017/09
  • 橋梁の維持管理支援のための３次元計測点群処理とその応用  [Invited]
    伊達宏昭
    ３Dレーザスキャニング＆イメージングシンポジウム2016  2016/11
  • レーザ計測による構造物のモデリングと維持管理支援技術  [Invited]
    伊達宏昭
    復興加速化プロジェクト～3次元技術活用フォーラム～  2016/10
  • 点群処理の基礎  [Invited]
    伊達宏昭
    点群処理基礎技術講習会  2016/09
  • Registration of 3D Scan Data of Large-Scale Environments acquired from Various Scanning Systems  [Invited]
    Hiroaki Date
    3D レーザスキャニング＆イメージングシンポジウム2015  2015/11
  • 点群の近傍探索と特徴抽出  [Invited]
    伊達宏昭
    点群処理基礎技術講習会  2015/09
  • 主成分分析とセグメンテーション  [Invited]
    伊達宏昭
    点群処理基礎技術講習会  2014/10
  • Registration of Point Clouds of Large-Scale Environments using Point Projection Images  [Invited]
    Hiroaki Date
    3D-Laser-scanning and Imaging Symposium JAPAN 2014  2014/09
  • 大規模環境の3次元レーザ計測とモデリング技術  [Invited]
    伊達宏昭
    2014年度精密工学会春季大会学術講演会シンポジウム  2014/03
  • 効率的CAEのための有限要素解析用メッシュの編集技術  [Invited]
    伊達宏昭
    第7回北海道CAE利用技術研究会  2013/09
  • 主成分分析とセグメンテーション  [Invited]
    伊達宏昭
    精密工学会 点群処理基礎技術 講習会  2013/09
  • 形状・コンテクスト特徴を用いた市街地レーザ計測点群からの柱状物体認識  [Not invited]
    伊達宏昭, 横山博貴, 金井理, 武田浩志
    ViEW2012  2012/12
  • Point Cloud Processing & Applications  [Not invited]
    Satoshi Kanai, Hiroaki Date
    SPAR Europe 2012 University Pavilion  2012/11
  • Dimension-Driven Deformation and Quality Improvement of Finite Element Meshes  [Invited]
    Hiroaki Date
    4th KMU-HU Joint Workshop  2012/11
  • 点群のセグメンテーション／領域成長法とRANSAC  [Invited]
    伊達宏昭
    精密工学会 点群処理基礎技術講習会  2012/09
  • MMS計測点群からの柱状物体抽出  [Invited]
    伊達宏昭
    動体計測研究会(ARIDA)  2012/09
  • ONOSATO Masahiko, TANAKA Fumiki, DATE Hiroaki
    Manufacturing Systems Division Conference  2007/07 
    Manufacturing activities in the industries are now deelply associated with advanced information technologies. A complex manufacturing space (CMS) is a formalization of a manufacturing system synthesized by a real system and a virtal system. In this paper, the interface betweeen human users and a CMS is mainly discussed, after the brief introduction of a CMS. Universal pointing is a key technology which enables a user to easily indicate various types of objects in a CMS with many input devices. Cyber annotation is a intension recording method to the indicated object by universal pointing. A ...
  • Tanaka Fumiki, Watanabe Masashi, Onosato Masahiko, Date Hiroaki
    情報科学技術フォーラム一般講演論文集  2006/08
  • Watanabe Masashi, Tanaka Fumiki, Onosato Masahiko, Date Hiroaki
    情報科学技術フォーラム一般講演論文集  2006/08
  • Date Hiroaki, Kanai Satoshi, Kishinami Takeshi, Nishigaki Ichiro
    Manufacturing Systems Division Conference  2006/06 
    With the progress of 3D scanning technology and storing mesh data to 3D model databases, the use of the meshes obtained by scanning and DB querying in CAE have been strongly required in addition to those obtained from traditional meshing of solid models. In this paper, we introduce our multiresolution mesh modeling system that can satisfy above requirements. Our system includes the functions that allow us to use several kinds of meshes in the CAE ; mesh properties control, mesh density control, feature suppression, and mesh combining. The effective use of them in the CAE is also described.
  • 伊達 宏昭
    精密工学会秋季大会. シンポジウム資料  2005/09
  • Date Hiroaki, Kanai Satoshi, Kishinami Takeshi, Iwakoshi Mutsuro, Kobayashi Masayoshi
    IPSJ SIG Notes  2005/05 
    In this paper, we introduce a design system of textured shapes with small bumps using mesh-modeling techniques. Our system consists of three functions: 1) texture mesh data acquisition based on 3D scanning of sample texture material and texture extraction from existing textured models, 2) digital data processing of the texture mesh, and 3) textured shape modeling by combining meshes according to the user-specified region or direction of texture. These functions allow us to achieve effective textured shape design and prototyping.
  • Shimizu Takafumi, Date Hiroaki, Kanai Satoshi, Kishinami Takeshi
    IPSJ SIG Notes  2005/05 
    In this paper, we propose a mesh smoothing method with feature edge identification for mesh models including the measurement noise obtained from 3D scanner. First, by doing the eigen analysis of normal voting tensor, mesh edge groups that compose the feature edges can be extracted. Second, a bilateral filtering is applied to the extracted mesh edge groups in order to generate smooth edges along feature edge directions. Finally, by applying modified bilateral filtering to the overall mesh, the mesh model is obtained where the feature edges are smoothed along their directions and measurement ...
  • NISHIGAKI Ichiro, DATE Hiroaki, KANAI Satoshi
    年次大会講演論文集 : JSME annual meeting  2004/09 
    We have developed an appearance-design-CAD-coupled simulation framework that will enable engineers to perform analysis simulations during the appearance design process. This is not only a prototype process, but also the most innovative product design process to date. We applied multi-resolution representation technology to an automatic mesh generation system, in order to obtain low-resolution analysis meshes from high-resolution appearance design meshes. Because engineers are able to design appearance and function all at once, we can eliminate redesigns caused by design defects in the origi...
  • Date Hiroaki, Kanai Satoshi, Kishinami Takeshi, Iwakoshi Mutsuro, Kobayashi Masayoshi
    年次大会講演論文集 : JSME annual meeting  2004/09 
    The surface of many industrial products can be considered to have geometries consisting of a base shape and surface textures, such as detailed geometrical patterns, logotypes and symbols. In this paper, we propose a textured shape design method based on mesh-based texture integration, and introduce an efficient prototyping system of the textured shapes using proposed method and stereo lithography. In this system, we can simply generate the mesh model with texture, and the resulting mesh model can be directly applicable to stereo lithography. Therefore, prototypes of textured shapes can be p...
  • Mizoguchi Tomohiro, Date Hiroaki, Kanai Satoshi, Kishinami Takeshi
    年次大会講演論文集 : JSME annual meeting  2004/09 
    Recently, triangular mesh models are widely used in product design and manufacturing. However, too many triangular patches are required for representing complex shapes accurately and it is also difficult to handle a meaningful set of triangular faces. To solve these problems, we propose a feature edge extraction method of triangular meshes based on segmentation using modified Watershed method and wide range normal evaluation. The proposed method robustly extracts feature edges from noisy mesh models, and enable to handle mesh models efficiently.
  • ENDO Yui, DATE Hiroaki, Kanai Satoshi, Kishinami Takeshi
    年次大会講演論文集 : JSME annual meeting  2004/09 
    In terms of smooth surface generation over arbitrary topological mesh, simplicity of geometric calculation, and easiness of LOD, subdivision surface has the attractive features as a surface to be fit in reverse engineering (RE). Recently, several fitting algorithms have been proposed for RE using subdivision surfaces. However, these are not suitable for RE in the industrial design process where the physical mock-up models have very complex product geometries. To solve this problem, we propose a new method for fitting a Loop subdivision surface to a given high resolution point cloud by using...
  • 伊達 宏昭, 金井 理, 岸浪 建史
    精密工学会大会学術講演会講演論文集  2002/10
  • DATE Hiroaki, KANAI Satoshi, KISHINAMI Takeshi
    情報科学技術フォーラム一般講演論文集  2002/09
  • 伊達 宏昭, 金井 理, 岸浪 建史
    精密工学会大会学術講演会講演論文集  2002/03
  • 金井 理, 伊達 宏昭, 岸浪 建史
    精密工学会大会学術講演会講演論文集  2001/09
  • 伊達 宏昭, 金井 理, 岸波 建史
    精密工学会大会学術講演会講演論文集  2001/09
  • KANAI Satoshi, DATE Hiroaki, KISINAMI Takeshi
    The ... Factory Automation Conference  2001/03 
    In the operation planning of 3-D free-form machining for die and cavity shapes, a series of intermediate shape models must be designed as the references of NC programming. In this paper, we apply a new wavelet-based multi-resolution analysis to the representation of a series of intermediate shape models for free-form surface machining. The proposed wavelet-based approach enables very compact data representation for these models, and enables the geometric relations between each resolution model to be designed so as to avoid overcut and to level the cutting loads. The effectiveness of the app...
  • Date Hiroaki, Kanai Satoshi, Kishinami Takeshi
    IPSJ SIG Notes  2001/02 
    The surface of many industrial products can be considered to have geometries composed both of base shape and surface detail.From design point of view, it is efficient design the base shape and surface detail independently.However, only base shape is often required in some applications, such as analysis, machining, and display for this type of composed shape.In this paper, to realize the flexible and efficient modeling for a mesh model with surface detail and its efficient data processing, we propose a method for integrating the surfave datail with base shape, and the multiresolution represe...
  • MIURA Yuki, DATE Hiroaki, KANAI Satoshi
    IPSJ SIG Notes  2001/02 
    A multi-resolution representation and its LOD control become necessary for efficiently processing a texture-mapped polygonal model with huge faces and high-resolution texture images.For this purpose, first we propose a re-meshing algorithm where the texture-mapped polygonal model with arbitrary topology can be converted into the one with semi-regular topology suitable for wavelet transform.Then, we discuss how to compose the multi-resolution representation of the texture-mapped polygonal model where the resolutions of the polygon geometry and the texture image can be individually controlled...
  • 三浦 夕季, 伊達 宏昭, 金井 理, 岸浪 建史
    精密工学会大会学術講演会講演論文集  2000/09
  • 伊達 宏昭, 金井 理, 岸浪 建史
    精密工学会大会学術講演会講演論文集  2000/09
  • 伊達 宏昭, 金井 理, 岸浪 建史
    精密工学会大会学術講演会講演論文集  2000/03
  • 三浦 夕季, 伊達 宏昭, 金井 理, 岸浪 建史
    精密工学会大会学術講演会講演論文集  2000/03
  • 伊達 宏昭, 金井 理, 岸浪 建史
    精密工学会大会学術講演会講演論文集  1999/09
  • 伊達 宏昭, 金井 理, 岸浪 健史
    精密工学会大会学術講演会講演論文集  1999/03
  • 金井 理, 伊達 宏昭, 岸浪 健史
    精密工学会大会学術講演会講演論文集  1999/03
  • 伊達 宏昭, 金井 理, 岸浪 建史
    精密工学会大会学術講演会講演論文集  1998/09

Association Memberships

  • INFORMATION PROCESSING SOCIETY OF JAPAN   THE JAPAN SOCIETY FOR PRECISION ENGINEERING   

Research Projects

  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
    Date (from‐to) : 2021/04 -2025/03 
    Author : 田中 覚, 陳 延偉, 矢野 桂司, 李 亮, 長谷川 恭子, 伊達 宏昭, 坂本 尚久, 山口 欧志, 坂野 雄一
  • 点品質最適化に基づく環境3次元計測点群データ処理手法の開発
    文部科学省：科学研究費補助金(基盤研究(C))
    Date (from‐to) : 2018/04 -2021/03 
    Author : 伊達宏昭
  • 文部科学省：科学研究費補助金(基盤研究(C))
    Date (from‐to) : 2014/04 -2017/03 
    Author : 伊達宏昭
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
    Date (from‐to) : 2014/04 -2016/03 
    Author : Kanai Satoshi, DATE HIROAKI
     
    The goal of this research is to realize the accessibility evaluation of "as-built" environments based on the detailed human behavior simulation. To this end, we propose a method where as-built 3D environment models can be constructed in a fully automatic way from laser-scanned 3D point clouds measured from as-built environments. Additionally, we propose an advanced walking simulation function of the digital human model (DHM) in the as-built environment models. The proposed simulation enabled a DHM to automatically walk utilizing the functions of the global path findings, the walking path location control, the local collision avoidance and the walking motion generation. Moreover, we applied our modeling and simulation algorithms to the complex as-built environments such as a two-storey indoor environment, and an outdoor environment which includes slopes. The efficiency and effectiveness of the modeling and simulation were confirmed.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2012/04 -2015/03 
    Author : KANAI Satoshi, DATE Hiroaki, MIZOGUCHI Tomohiro
     
    The purpose of this research is to develop advanced and fully-automated software for object recognition and modeling from massive laser scanned point clouds captured from large-scale equipment with current status to automatically construct “as-built equipment model” where each object in the equipment is semantically annotated. The software also aims for updating the as-built model continuously over time with minimum effort of additional laser scanning operation over long term, and for proposing a set of common and invariant primitive point clouds processing algorithms to support the recognition and modeling chemical plants, large-buildings, electric power plants etc.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2012 -2013 
    Author : DATE Hiroaki
     
    In this research, a set of point cloud data processing algorithms for generating mesh models of large-scale environments from point clouds acquired by laser scanning was developed. In particular, the following algorithms were developed: (1) efficient registration algorithms of point clouds of large-scale environments, (2) an effective point cloud rendering algorithm to support easy visual understanding of the scanned environments, (3) a segmentation algorithm of point clouds of urban environments, (4) pole-like object recognition and classification algorithms from point clouds, and (5) mesh modeling algorithms of the objects in urban environments. The effectiveness of each algorithm was evaluated through the experiments using several point clouds, and it was confirmed that the mesh models of the pole-like objects and street trees could be generated efficiently from point clouds of urban environments using the developed algorithms.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2011 -2012 
    Author : KANAI Satoshi, DATE Hiroaki, SHIBATA Takayuki, KAWASHIMA Takahiro
     
    The objective of this study is to enable designers who are not necessarily the experts on MEMS(Micro Electro Mechanical Systems) manufacturing processes to easily plan the feasible and low-cost manufacturing processes of MEMS devices. To achieve this, a prototype of the computer-aided process planning system of MEMS devices was developed where (1) all feasible process plans of the device could be searched for and (2) device shapes and structures easier to fabricate could be estimated automatically based on the multi-resolution mesh model of the devices.
  • Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 2009 -2011 
    Author : Satoshi KANAI, Yoshiyuki SHIROMA, Hiroaki DATE, Masaaki MOCHIMARU
     
    The purpose of the research is to build a virtual ergonomic assessment system for handheld products such as digital cameras based on the Digital Hand. The Digital Hand is a model which can simulate the 3D precise outer skin geometry and finger kinematic structure of human hands. Ease-of-grasp and ease-of fingered operation can be quantitatively evaluated in the system. The following functions were developed ; (1) Constructing Digital Hand models based on MRI measurement of human hands, (2) Optimization-based grasp posture synthesis, (3) Quantitative estimation of ease-of-grasp based on muscle-skeletal model, (4) Quantitative estimation of ease-of fingered operation, and (5) Efficient contact deformation simulation between hand and product. Moreover, the developed software was applied to evaluating the product shape in real design environments of manufactures.
  • Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(若手研究(B))
    Date (from‐to) : 2009 -2010 
    Author : Hiroaki DATE
     
    In this research, a sketch-based tetrahedral mesh modeling method and a tetrahedral mesh deformation method based on dimensions were developed for efficient use of 3D geometric models in the product development. Tetrahedral mesh generation and modification according to user's manipulations similar to the current 3D CAD systems were achieved, thus the basic technologies of cooperation between the solid and mesh models in CAD/CAE were developed.
  • Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 2007 -2008 
    Author : Satoshi KANAI, Hiroaki DATE
     
    本研究は, 工業用X線CT計測データから全自動・高品質な3次元形状モデルを構築する技術を実現すべく, 実工業製品の大規模なX線CT計測メッシュから, エンジニアリングで要求される高品質な3次元形状モデルのフィーチャ認識を, 高精度に, 安定かつ自動で, しかも高速に行なえるアルゴリズムと, 認識の基本となる高精度なメッシュ曲率算出アルゴリズムを開発し, そのアルゴリズムが十分な実用性をもつことを検証した.
  • 文部科学省：科学研究費補助金(基盤研究(B))
    Date (from‐to) : 2006 -2007 
    Author : 小野里 雅彦, 田中 文基, 伊達 宏昭
     
    実世界の存在物と仮想世界の存在物とが相互に連関し,ある種の双対性を実現した複素生産空間の概念の定式化と,それに基づくシステム開発を実施した.複素生産空間の概念的な図式として,実世界面と仮想世界基準面からなる抽象的な空間を考え,世界に対する記述が時間の進行とともに意味が推移していくことを示した.システムの開発に関しては,実-仮想の表現実体が混在する作業環境において,それらを同一の指示デバイスを用いて指示することができるユニバーサルポインティングシステムの開発を行った.また,発話による直示表現による作業環境中の対象物指示と音声認識とテキスト処理を用いた発話記録システムを開発することで,作業環境において,指示対象と発話内容を連携させた形での技術情報の蓄積および取り出し可能とした.また,3次元の対象物に対する情報の付与と参照を直感的に行うためのデバイスとして拡張現実感を使用した3次元ユーザインタフェースを開発し,サイバーアノテーション環境の構築とその有効性を検証した.また,サイバーフィールドのモデリングに関しては仮想環境中で生産の業務を行う仮想作業者の開発,実環境に対する3次元計測データからCAD等で形状定義された対象物を認識する手法の開発,時間変化をする3次元世界を4次元の形状としてモデリングする4次元メッシュモデリングシステムなどを開発し,複素生産空間を実現するための基盤を整備した.以上の研究成果により,複素生産空間の概念提示からそれを実現する際に必要となる主要な技術の開発を行うことができた.今後は実生産の支援を行うための手法とシステムの拡張整備が課題となる.
  • Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 2005 -2006 
    Author : Satoshi KANAI, Hiroaki DATE
     
    The purpose of this research is to develop software where legacy mesh models for analysis can be retrieved using a query of a hand written sketch or sampled point data from physical model, where a new mesh model for analysis for a new design idea can be obtained quickly by deforming the legacy models so as to fit to the sketch or sampled points. Therefore, in this research, advanced mesh modeling operations which stand geometric modeling ability similar to conventional solid modeling operations and mesh-generation for analysis were developed. The research results can be summarized as follows. 1) A content based mesh retrieval function from hand-written sketch has been developed where mesh models which have similar projected view to the sketch can be retrieved using generic Fourier descriptor and local binary patterns. 2) A mesh-assembly function has been developed where two complex mesh models in contact can be merged into one model using surface offsetting and edge-collapse operations for tetrahedral mesh. 3) A mesh feature removal function has been developed where the small form features on the mesh model such as holes, slots and bosses can be automatically recognized and these features can be removed or regenerated using our LOD control algorithm. 4) Feature recognition and mesh deforming functions have been developed where partial surface regions on the large scale mesh which can be approximated to a singe kind of analytic surface can be automatically segmented, and where geometry of the mesh can be deformed in the dimension driven way using a special deforming function based on the barycentric coordinate interpolation for mesh. These research results were presented in public in the form of 10 research papers and 2 patent applications.
  • 日本学術振興会：科学研究費助成事業 特別研究員奨励費
    Date (from‐to) : 2000 -2002 
    Author : 伊達 宏昭
     
    本研究では,三角形メッシュモデルの多重解像度表現に基づく有限要素解析・干渉判定処理の効率化に関する研究を行い,以下の成果を得た. 1 有限要素解析のための多重解像度メッシュ生成 設計形状の強度評価のための有限要素解析では,解析処理の効率化のために,形状の詳細フィーチャが選択的に除去され,低い解像度,高いメッシュ品質を持つメッシュモデルが要求される.本研究では,これらの要求事項を満足するため,形状の高周波成分を詳細フィーチャとみなし,メッシュモデルのフィルタリングにより得られる局所パワースペクトルと,メッシュ品質を決定付ける要素歪・頂点価数の評価に基づいてメッシュ低解像度化順序を決定し,元形状,又は,フィルタリング後の形状を近似しながらメッシュを低解像度化することにより,詳細フィーチャが選択的に除去・保存されたメッシュ品質の高い低解像度メッシュを得られる多重解像度表現生成法を開発した.以上の成果より,高密度三角形メッシュモデルからの,有限要素解析に適した解像度・性質を持つメッシュモデル生成が可能となった. 2 干渉判定のための多重解像度メッシュ生成 本研究では,昨年度開発した干渉判定用多重解像度表現より得られる低解像度メッシュを,初期干渉可能性検出に用い,その検出結果に従って,干渉個所を絞り込んだ効率の良い干渉判定処理を実現するため,多重解像度表現におけるメッシュ階層性の2分木表現に基づく,干渉検出個所近傍のみを高解像度化する適応的解像度制御法を開発した.また,提案法における更なる干渉判定処理効率化のために,干渉可能性の低い形状の凹部分や小面分から成る部分を優先的に,かつ,線形計画法に基づいて形状膨張(干渉過大評価量)を最小化するメッシュ低解像度化を実現した.以上の成果より,干渉個所の絞り込み,処理速度・精度制御が可能な,三角形メッシュモデルを用いた効率の良い干渉判定処理が可能となった.

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