研究者データベース

田中 章(タナカ アキラ)
情報科学研究院 情報理工学部門 数理科学分野
教授

基本情報

所属

  • 情報科学研究院 情報理工学部門 数理科学分野

職名

  • 教授

学位

  • 博士(工学)(北海道大学)

論文上での記載著者名

  • Akira Tanaka
  • 田中 章

ホームページURL

J-Global ID

研究キーワード

  • 標本化理論   画像信号処理   機械学習理論   音響信号処理   

研究分野

  • 情報通信 / ヒューマンインタフェース、インタラクション
  • 情報通信 / データベース
  • 情報通信 / ヒューマンインタフェース、インタラクション
  • 情報通信 / データベース
  • 情報通信 / 知能情報学

職歴

  • 2016年 - 現在 北海道大学大学院情報科学研究科 教授
  • 2011年 - 2016年 北海道大学大学院情報科学研究科 准教授
  • 2007年 - 2011年 北海道大学大学院情報科学研究科 助教
  • 2004年 - 2007年 北海道大学大学院情報科学研究科 助手
  • 2004年 - 2007年 Research Associate
  • 2000年 - 2004年 北海道大学大学院工学研究科 助手
  • 2000年 - 2004年 Research Associate
  • 1996年 - 1998年 松下通信工業株式会社

学歴

  • 1998年04月 - 2000年09月   北海道大学大学院   工学研究科   システム情報工学専攻博士後期課程
  • 1994年04月 - 1996年03月   北海道大学大学院   工学研究科   情報工学専攻修士課程
  • 1990年04月 - 1994年03月   北海道大学   工学部   情報工学科

所属学協会

  • IEEE   日本音響学会   電子情報通信学会   ASJ   IEICE   ASA   IEEE   

研究活動情報

論文

  • Akira Tanaka, Hideyuki Imai
    ICASSP 2020 - 2020 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) 3867 - 3871 2020年05月 [査読有り][通常論文]
  • Tracking the Burden Surface Radial Profile of a Blast Furnace by a B-mode Mechanical Swing Radar System
    Jiuzhou Tian, Akira Tanaka, Yue Meng, Qingwen Hou, Xianzhong Chen
    ISIJ International 60 2 297 - 307 2020年02月 [査読有り][通常論文]
  • A Fast Cross-Validation Algorithm for Kernel Ridge Regression by Eigenvalue Decomposition
    田中 章, 今井 英幸
    IEICE Transactions on Electronics, Communications and Computer Sciences E102-A 9 1317 - 1320 2019年09月 [査読有り][通常論文]
  • Radar detection-based modeling in a blast furnace: a prediction model of burden surface descent speed
    J. Tian, A. Tanaka, Q. Hou, X. Chen
    Metals 9 5 1 - 23 2019年05月 [査読有り][通常論文]
  • 基底選択に基づく教師付NMF
    小松 美咲, 田島 優, 田中 章
    第33回信号処理シンポジウム講演論文集 47 - 48 2018年11月 [査読無し][通常論文]
  • 座標降下法を用いた高速マルチチャネルNMFアルゴリズム
    田島 優, 田中 章
    第33回信号処理シンポジウム講演論文集 51 - 52 2018年11月 [査読無し][通常論文]
  • Binary Sparse Representation Based on Arbitrary Quality Metrics and Its Applications
    T. Ogawa, S. Takahashi, N. Wada, A. Tanaka, M. Haseyama
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E101-A 11 1776 - 1785 2018年11月 [査読有り][通常論文]
  • Radar Detection-based Modeling in a Blast Furnace: a Prediction Model of Burden Surface Shape after Charging
    J. Tian, A. Tanaka, Q. Hou, X. Chen
    ISIJ International 58 11 1999 - 2008 2018年11月 [査読有り][通常論文]
  • Kernel-Induced Sampling Theorem for Translation-Invariant Reproducing Kernel Hilbert Spaces with Uniform Sampling
    田中 章
    2018 IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP2018) 4554 - 4558 2018年04月 [査読有り][通常論文]
  • マルチチャネルNMFにおける空間相関行列の初期値設定法の性能評価
    田島 優, 田中 章
    電子情報通信学会技術研究報告, 信号処理 117 515 161 - 162 2018年03月 [査読無し][通常論文]
  • マハラノビス距離学習と主成分マッチングを用いた教師付クラスタリング
    杉江 祐哉, 田中 章
    電子情報通信学会技術研究報告, 信号処理 117 515 141 - 142 2018年03月 [査読無し][通常論文]
  • 一次元斜射影を用いた教師付NMFによる音源分離
    小松 美咲, 田中 章
    電子情報通信学会技術研究報告, 信号処理 117 515 133 - 134 2018年03月 [査読無し][通常論文]
  • 斉藤 優樹, 田中 章
    APSIPA Annual Summit & Conference 2017 ID : 78  2017年12月 [査読有り][通常論文]
  • マルチチャネルNMFにおける空間相関行列の初期値設定法
    田島 優, 田中 章
    第32回信号処理シンポジウム講演論文集 77 - 78 2017年11月 [査読無し][通常論文]
  • Takahiro Ogawa, Akira Tanaka, Miki Haseyama
    IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS E100D 10 2614 - 2626 2017年10月 [査読有り][通常論文]
     
    A Wiener-based inpainting quality prediction method is presented in this paper. The proposed method is the first method that can predict inpainting quality both before and after the intensities have become missing even if their inpainting methods are unknown. Thus, when the target image does not include any missing areas, the proposed method estimates the importance of intensities for all pixels, and then we can know which areas should not be removed. Interestingly, since this measure can be also derived in the same manner for its corrupted image already including missing areas, the expected difficulty in reconstruction of these missing pixels is predicted, i.e., we can know which missing areas can be successfully reconstructed. The proposed method focuses on expected errors derived from the Wiener filter, which enables least-squares reconstruction, to predict the inpainting quality. The greatest advantage of the proposed method is that the same inpainting quality prediction scheme can be used in the above two different situations, and their results have common trends. Experimental results show that the inpainting quality predicted by the proposed method can be successfully used as a universal quality measure.
  • Akira Tanaka
    2017 12th International Conference on Sampling Theory and Applications, SampTA 2017 318 - 321 2017年09月01日 [査読有り][通常論文]
     
    In this paper, we discuss a function reconstruction problem by kernel regressors in which the autocorrelation of the unknown true function is given a priori. In general, a reconstructed function in the kernel regression problem, using a certain reproducing kernel Hilbert space, is represented by a linear combination of the corresponding kernel specified by each input point. We introduce a framework to reflect the autocorrelation prior of the unknown true function on the estimation of the coefficients for the linear combination and give a closed-form solution of the optimal coefficients. We also give numerical examples, using the popular Gaussian kernel, to confirm the behavior of the proposed method.
  • 田中 章
    日本音響学会誌 73 9 577 - 584 2017年09月 [査読無し][招待有り]
  • Iterative Zero Phase Method for White and Impulse Noise Reduction
    田中 章, 川村 新
    22th International Conference on Digital Signal Procerssing ID:42  2017年08月 [査読有り][通常論文]
  • ブロックベース線形回帰を利用したデモザイキング
    河野 克也, 田中 章
    電子情報通信学会論文誌D J100-D 5 605 - 612 2017年05月 [査読有り][通常論文]
  • シングルチャネルNMFを用いたマルチチャネルNMFの初期値設定法の性能評価
    田島 優, 田中 章
    電子情報通信学会技術研究報告, 信号処理 116 475 67 - 70 2017年03月 [査読無し][通常論文]
  • 最適正規化に基づくB-スプライン開曲線類似度計算法の改良
    久保内 悠馬, 田中 章
    電子情報通信学会技術研究報告, 信号処理 116 475 83 - 86 2017年03月 [査読無し][通常論文]
  • Akira Tanaka, Hideyuki Imai
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E100A 3 877 - 887 2017年03月 [査読有り][通常論文]
     
    The solution of the standard 2-norm-based multiple kernel regression problem and the theoretical limit of the considered model space are discussed in this paper. We prove that 1) The solution of the 2-norm-based multiple kernel regressor constructed by a given training data set does not generally attain the theoretical limit of the considered model space in terms of the generalization errors, even if the training data set is noise-free, 2) The solution of the 2-norm-based multiple kernel regressor is identical to the solution of the single kernel regressor under a noise free setting, in which the adopted single kernel is the sum of the same kernels used in the multiple kernel regressor; and it is also true for a noisy setting with the 2-norm-based regularizer. The first result motivates us to develop a novel framework for the multiple kernel regression problems which yields a better solution close to the theoretical limit, and the second result implies that it is enough to use the single kernel regressors with the sum of given multiple kernels instead of the multiple kernel regressors as long as the 2-norm based criterion is used.
  • シングルチャネルNMFを用いたマルチチャネルNMFの初期値設定法
    田島 優, 田中 章
    第31回信号処理シンポジウム講演論文集 71 - 72 2016年11月 [査読無し][通常論文]
  • B-スプラインを用いた曲線類似度計算法の性能評価
    久保内 悠馬, 田中 章
    第31回信号処理シンポジウム講演論文集 218 - 221 2016年11月 [査読無し][通常論文]
  • 再生核ヒルベルト空間の積空間におけるグラム行列の近似計算
    田中 章
    第31回信号処理シンポジウム講演論文集 405 - 408 2016年11月 [査読無し][通常論文]
  • 走塁能力を考慮した打順の得点期待値算出モデル
    池田 啓, 田中 章
    情報処理北海道シンポジウム2016講演論文集 177 - 180 2016年10月 [査読無し][通常論文]
  • QZ法の反復計算における変換行列の精緻化
    橋本 樹, 田中 章
    情報処理北海道シンポジウム2016講演論文集 193 - 194 2016年10月 [査読無し][通常論文]
  • B-スプライン曲線を用いた高速な曲線類似度計算法
    久保内 悠馬, 田中 章
    電子情報通信学会技術研究報告 115 521 329 - 334 2016年03月 [査読無し][通常論文]
  • 修正零位相信号解析に基づく雑音抑制
    田中 章, 安間 悠貴, 川村 新
    電子情報通信学会技術研究報告 115 521 153 - 157 2016年03月 [査読無し][通常論文]
  • 多項式近似に基づく褪色カラーフィルムのデジタル画像復元
    田中 章, 鍵谷 貴宏, 宮松 武志, 波江 一馬, 奥山 敏康
    電子情報通信学会論文誌D J99-D 3 367 - 376 2016年03月 [査読有り][通常論文]
  • Koji Takamiya, Akira Tanaka
    THEORY AND DECISION 80 1 33 - 41 2016年01月 [査読有り][通常論文]
     
    This paper considers the computational complexity of the design of voting rules, which is formulated by simple games. We prove that it is an NP-complete problem to decide whether a given simple game is stable, or not.
  • Akira Tanaka, Hirofumi Takebayashi, Ichigaku Takigawa, Hideyuki Imai, Mineichi Kudo
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E98A 11 2315 - 2324 2015年11月 [査読有り][通常論文]
     
    For the last few decades, learning with multiple kernels, represented by the ensemble kernel regressor and the multiple kernel regressor, has attracted much attention in the field of kernel-based machine learning. Although their efficacy was investigated numerically in many works, their theoretical ground is not investigated sufficiently, since we do not have a theoretical framework to evaluate them. In this paper, we introduce a unified framework for evaluating kernel regressors with multiple kernels. On the basis of the framework, we analyze the generalization errors of the ensemble kernel regressor and the multiple kernel regressor, and give a sufficient condition for the ensemble kernel regressor to outperform the multiple kernel regressor in terms of the generalization error in noise-free case. We also show that each kernel regressor can be better than the other without the sufficient condition by giving examples, which supports the importance of the sufficient condition.
  • Akira Tanaka
    2015 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA) 242 - 245 2015年 [査読有り][通常論文]
     
    It is widely recognized that the kernel-based learning scheme is one of powerful tools in the field of machine learning. Recently, learning with multiple kernels, instead of a single kernel, attracts much attention in this field. Although their efficacy was investigated in terms of practical sense, their theoretical grounds were not sufficiently discussed in the past studies. In our previous work, we theoretically analyzed the standard 2-norm-based multiple-kernel regressor, and proved that the solution of the multiple kernel regressor obtained by 2-norm-based criterion reduces to the solution of the single kernel regressor with the sum of the kernels. However, the proof was hard to understand intuitively. In this work, we give a simple proof for the theorem in which the roles of the 2-norm-based criteria are intuitively convincing.
  • Akira Tanaka
    2015 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING (ICASSP) 2046 - 2050 2015年 [査読有り][通常論文]
     
    Theoretical validity of empirical error minimization in multiple kernel regressors is discussed in this paper. Generalization error of a kernel machine is usually evaluated by the induced norm of the difference between an unknown true function and an estimated one in an appropriate reproducing kernel Hilbert space. It is well known that empirical error minimization also achieves the minimum generalization error in single kernel regressors. However, it is not clarified whether or not that is true for multiple kernel regressors. Moreover, possibility of constructing the minimizer of the generalization error by a given training date set is not also clarified. In this paper, we give negative conclusions for these problems through theoretical analyses on the generalization error of multiple kernel regressors and also give an example by popular Gaussian kernels.
  • マルチカーネル回帰とアンサンブルカーネル回帰の汎化誤差解析
    田中 章, 瀧川 一学, 今井 英幸, 工藤 峰一
    第29回信号処理シンポジウム講演論文集 120 - 123 2014年11月 [査読無し][通常論文]
  • ブロックベース線形回帰と非局所的冗長性を利用したデモザイキング
    河野 克也, 田中 章
    第29回信号処理シンポジウム講演論文集 533 - 534 2014年11月 [査読無し][通常論文]
  • 一般化固有値展開に基づく信号部分空間推定と斜射影を用いたDOA推定
    安間 悠貴, 田中 章
    第29回信号処理シンポジウム講演論文集 476 - 477 2014年11月 [査読無し][通常論文]
  • 非定常信号選択型独立成分分析によるブラインド信号源分離
    張 ケン, 田中 章
    第29回信号処理シンポジウム講演論文集 277 - 278 2014年11月 [査読無し][通常論文]
  • アンサンブルカーネル回帰とマルチカーネル回帰の汎化性能に関する一考察
    竹林 裕史, 田中 章
    第29回信号処理シンポジウム講演論文集 425 - 426 2014年11月 [査読無し][通常論文]
  • "Theoretical Analyses on Ensemble and Multiple Kernel Regressors
    田中 章, 瀧川 一学, 今井 英幸, 工藤 峰一
    Proceedings of the 6th Asian Conference on Machine Learning (ACML2014) 2014年11月 [査読有り][通常論文]
  • 斜射影を用いたMUSIC法によるDOA推定
    田中 章, 今井 英幸
    日本音響学会2014年春季研究発表会講演論文集 CD-ROM:3-2-1  2014年03月 [査読無し][通常論文]
  • Akira Tanaka, Ichigaku Takigawa, Hideyuki Imai, Mineichi Kudo
    STRUCTURAL, SYNTACTIC, AND STATISTICAL PATTERN RECOGNITION 8621 273 - 281 2014年 [査読有り][通常論文]
     
    Kernel-based learning is widely known as a powerful tool for various fields of information science such as pattern recognition and regression estimation. For the last few decades, a combination of different learning machines so-called ensemble learning, which includes learning with multiple kernels, have attracted much attention in this field. Although its efficacy was revealed numerically in many works, its theoretical grounds are not investigated sufficiently. In this paper, we discuss regression problems with a class of kernels and show that the generalization error by an ensemble kernel regressor with the class of kernels is smaller than the averaged generalization error by kernel regressors with each kernel in the class.
  • Akira Tanaka, Hideyuki Imai
    2014 IEEE WORKSHOP ON STATISTICAL SIGNAL PROCESSING (SSP) 300 - 303 2014年 [査読有り][通常論文]
     
    In the MUSIC-based direction of arrival (DOA) estimation technique, the orthogonal projection of a steering vector onto the socalled noise subspace plays a crucial role. The noise subspace is defined as the orthogonal complement of the signal subspace spanned by the unknown true steering vectors of target signals, which implies that the correlation structure of noise does not contribute to the DOA estimation performance after the signal subspace is specified. In this paper, we introduce a novel noise subspace, called the proper noise subspace, which is a complementary subspace of the signal subspace and reflects the correlation structure of the noise; and construct a novel MUSIC-based DOA estimation algorithm based on the oblique projector onto the proper noise subspace along the signal subspace.
  • Akira Tanaka, Hideyuki Imai
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E97A 1 322 - 330 2014年01月 [査読有り][通常論文]
     
    In signal restoration problems, we expect to improve the restoration performance with a priori information about unknown target signals. In this paper, the parametric Wiener filter with linear constraints for unknown target signals is discussed. Since the parametric Wiener filter is usually defined as the minimizer of the criterion not for the unknown target signal but for the,filter, it is difficult to impose constraints for the unknown target signal in the criterion. To overcome this difficulty, we introduce a criterion for the parametric Wiener filter defined for the unknown target signal whose minimizer is equivalent to the solution obtained by the original formulation. On the basis of the newly obtained criterion, we derive a closed-form solution for the parametric Wiener filter with linear constraints.
  • 同時対角化解析解を用いたCVFFDIAGの収束性能改善
    室田 美帆, 田中 章
    第28回信号処理シンポジウム講演論文集 10 - 14 2013年11月 [査読無し][通常論文]
  • カーネル回帰を用いたJPEG再適用法によるJPEG画像の画質改善
    河野 克也, 田中 章
    第28回信号処理シンポジウム講演論文集 446 - 447 2013年11月 [査読無し][通常論文]
  • "A Sufficient Condition For Reproducing Kernel Hilbert Spaces Being Separable
    田中 章, 今井 英幸, 工藤 峰一
    第28回信号処理シンポジウム講演論文集 350 - 354 2013年11月 [査読無し][通常論文]
  • Katsuya Kohno, Akira Tanaka
    Proceedings of the IASTED International Conference on Signal and Image Processing, SIP 2013 368 - 373 2013年 [査読有り][通常論文]
     
    Estimation of missing entries in a multivariate data is one of classical problems in the field of statistical science. Linear regression with the EM algorithm is well known as one of popular approaches for this problem. When this approach is applied to block-based image inpainting problems, multiple candidates of estimate for a target lost pixel may be obtained. In our previous work, we proposed a denoising technique for multiple images using the convex combination which minimizes its variance of errors from a true image. In this paper, we propose a novel image in-painting method incorporating the application of the de-noising technique to multiple estimates for a target pixel. We also show several results of numerical experiments in order to verify the efficacy of the proposed method.
  • Miho Murota, Akira Tanaka
    Proceedings of the IASTED International Conference on Signal and Image Processing, SIP 2013 345 - 350 2013年 [査読有り][通常論文]
     
    In this paper, we try to improve the performance of the FFDiag algorithm, which is one of the state-of-the-art iteration-based approximate joint diagonalizers of a given set of real-valued symmetric matrices. The key idea of the improvement is pre-diagonalization by a closed-form joint diagonalizer whose computational cost is smaller than that of the FFDiag algorithm. Numerical experiments for approximate joint diagonalization of a set of real-valued symmetric matrices, that are randomly generated, are conducted to verify the efficacy of the proposed scheme in terms of computational costs and joint diagonalization performance.
  • Akira Tanaka
    2013 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP) 5450 - 5453 2013年 [査読有り][通常論文]
     
    In this paper, a sampling theorem for bandpass signals with uniformly spaced sampling points is discussed. We firstly show that a function space consisting of all functions with a specific bandpass property is a reproducing kernel Hilbert space and also give a closed-form of the corresponding reproducing kernel. Moreover, on the basis of the framework of the kernel-induced sampling theorem, we give a simple perfect reconstruction formula for the bandpass signals by uniformly spaced sampling points with the bandpass Nyquist rate, which is defined as twice the signal bandwidth, for the cases that the maximum frequency of the signals is identical to bandwidth multiplied by some positive integer.
  • Akira Tanaka, Katsuya Kohno
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E96-A 10 2066 - 2070 2013年 [査読有り][通常論文]
     
    In this paper, we propose a novel multi-frame image denoising technique, which achieves the minimum variance of noise. Zeromean and unknown variance white noise with an arbitrary distribution is considered in this paper. The proposed method consists of two parts. The first one is the estimation of the variance of noise for each image by considering the differences of all pairs of images. The second one is an actual denoising process in which the convex combination of all images with weight coefficients determined by the estimated variances is constructed. We also give an efficient algorithm by which we can obtain the same result by successive convex combinations. The efficacy of the proposed method is confirmed by computer simulations. Copyright © 2013 The Institute of Electronics, Information and Communication Engineers.
  • Image Inpainting by Block-Based Linear Regression with Optimal Block Selection
    Akira Tanaka, Takahiro Ogawa, Miki Haseyama
    Proceedings of APSIPA Annual Summit & Conference 2012 ID:8  2012年12月 [査読有り][通常論文]
  • JPEG再適用と画像データベースを利用したJPEG画質改善法の性能評価
    河野克也, 田中章
    第27回信号処理シンポジウム講演論文集 297 - 302 2012年11月 [査読無し][通常論文]
  • 非負値行列分解と基底ベクトルクラスタリングに基づく単一チャネル音楽信号分離
    小田智也, 田中章
    第27回信号処理シンポジウム講演論文集 380 - 384 2012年11月 [査読無し][通常論文]
  • 最適解選択を用いた同時対角化解析解の性能評価
    室田美帆, 田中章
    第27回信号処理シンポジウム講演論文集 328 - 332 2012年11月 [査読無し][通常論文]
  • NMFを用いた自動採譜における基底ベクトル数の決定手法
    水野賀文, 田中章
    第27回信号処理シンポジウム講演論文集 391 - 395 2012年11月 [査読無し][通常論文]
  • 画像データベースとJPEG再適用を利用したJPEG画像の画質改善
    河野 克也, 田中章
    電子情報通信学会技術研究報告, 回路とシステム 111 465 13 - 18 2012年03月 [査読無し][通常論文]
  • Katsuya Kohno, Akira Tanaka, Hideyuki Imai
    2012 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA ASC) ID:112  2012年 [査読有り][通常論文]
     
    Image compression is one of important technologies in the fields of image processing. JPEG has been commonly used for image compression. Since JPEG is a lossy compression method, decoded images exhibit visually unwanted noises. A need for techniques for improving the quality of JPEG images remains because there still exist many images compressed by JPEG today. Many methods for improving the quality of JPEG images have been proposed. Among them, a method based on reapplication of JPEG, which means compression and decoding, is recognized as one of efficient methods. In our previous study, we improved this method by incorporating an image database and novel distance measures between two images. In this paper, we propose a new distance measure between two images to improve the performance of our previous method. We also show some results of numerical experiments to verify the efficacy of the proposed criterion.
  • Akira Tanaka, Miho Murota
    2012 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA ASC) ID:44  2012年 [査読有り][通常論文]
     
    Joint diagonalization of a series of non-negative Hermitian matrices is one of important techniques in the fields of signal processing, such as blind source separation based on second order statistics. In our previous works, we introduced a closed-form solution of a joint diagonalizer of non-negative Hermitian matrices and also proposed a method for improving the performance of the solution for the cases where given series of Hermitian matrices are not jointly diagonalizable strictly. However, the performance of the method may degrade when the number of given Hermitian matrices are comparatively small. In this paper, we propose an improved version of the closed-form joint diagonalizer of given set of Hermitian matrices by increasing the number of Hermitian matrices virtually. Some numerical examples are also shown to verify the efficacy of the proposed method.
  • Akira Tanaka, Ryo Takahashi
    2012 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA ASC) ID:9  2012年 [査読有り][通常論文]
     
    Noise suppression of diffusion noise by microphone arrays is discussed in this paper. In our previous work, we proposed a method for jointly estimating signal and noise correlation matrices from observations with diffusion noise by using so-called crystal shape microphone arrays; and discussed the performance of the Wiener filter based on those correlation matrices. In this paper, we propose a novel method for noise suppression of diffusion noise based on the newly adopted spectral subtraction scheme with the estimated correlation matrices by our previous work. We also verify the efficacy of the proposed method by some computer simulations and show that the proposed method outperforms our previous method by the Wiener filter.
  • Akira Tanaka, Hideyuki Imai, Koji Takamiya
    2012 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP) 2001 - 2004 2012年 [査読有り][通常論文]
     
    Learning based on kernel machines is widely known as a powerful tool for various fields of information science including signal processing such as function estimation from finite sampling points. One of central topics of kernel machines is model selection, especially selection of a kernel or its parameters. In our previous works, we investigated the generalization error of a model space itself corresponding to a selected kernel in kernel regressors. In this paper, we discuss the generalization error in a model space corresponding to a selected kernel in kernel regressors; and prove that the variance of a learning result is reduced when we adopt a kernel corresponding to a larger reproducing kernel Hilbert space.
  • Akira Tanaka, Ichigaku Takigawa, Hideyuki Imai, Mineichi Kudo
    STRUCTURAL, SYNTACTIC, AND STATISTICAL PATTERN RECOGNITION 7626 345 - 353 2012年 [査読有り][通常論文]
     
    Learning based on kernel machines is widely known as a powerful tool for various fields of information science such as pattern recognition and regression estimation. An appropriate model selection is required in order to obtain desirable learning results. In our previous work, we discussed a class of kernels forming a nested class of reproducing kernel Hilbert spaces with an invariant metric and proved that the kernel corresponding to the smallest reproducing kernel Hilbert space, including an unknown true function, gives the best model. In this paper, we relax the invariant metric condition and show that a similar result is obtained when a subspace with an invariant metric exists.
  • トレース正規化による非負定値エルミート行列の同時対角化の性能改善
    田中章
    第26回SIPシンポジウム講演論文集 C3-3  2011年11月 [査読無し][通常論文]
  • KLダイバージェンスを用いたNMFアルゴリズムの変数選択に基づく高速化
    尾崎 大顕, 田中 章
    第29回信号処理シンポジウム講演論文集 423 - 424 2011年11月 [査読無し][通常論文]
  • 自己校正法における射影変換の推定精度の向上
    滝沢篤史, 田中章, 宮腰政明
    電子情報通信学会技術研究報告, 信号処理 110 440 229 - 233 2011年03月 [査読無し][通常論文]
  • カーネルリッジ回帰における低計算量モデル選択法
    武井亨, 田中章, 宮腰政明
    電子情報通信学会技術研究報告, 信号処理 110 440 185 - 190 2011年03月 [査読無し][通常論文]
  • 既知の基底ベクトルを考慮した NMF
    天野雄太, 田中章, 宮腰政明
    電子情報通信学会技術研究報告, 信号処理 110 440 137 - 141 2011年03月 [査読無し][通常論文]
  • 固有空間BPLP 法の補間精度に関する解析
    田中章, 小川貴弘, 長谷山美紀, 宮腰政明
    電子情報通信学会論文誌A J94-A 2 116 - 126 2011年02月 [査読有り][通常論文]
  • Yoshifumi Mizuno, Akira Tanaka, Masaaki Miyakoshi
    Proceedings - 2011 IEEE International Conference on Granular Computing, GrC 2011 468 - 472 2011年 [査読有り][通常論文]
     
    When composers and arrangers compose music, they depend not only on their sense, but also on music theory. Therefore, there is possibility of automatic composition and automatic arrangement by computers. Some studies on automatic composition using computers have been studied continuously for 50 years. For example, an automatic music composition based on counterpoint and imitation using stochastic models and a melody generation method using a tree structure of generative theory of tonal music, are cited as previous studies. In this paper, we propose a method of music interpolation by applying the Wiener filter to scores with missing parts. In addition, we propose a method of music arrangement based on the proposed interpolation method. © 2011 IEEE.
  • Yuta Amano, Akira Tanaka, Masaaki Miyakoshi
    Proceedings - 2011 IEEE International Conference on Granular Computing, GrC 2011 48 - 53 2011年 [査読有り][通常論文]
     
    Recently, a novel matrix factorization, named non-negative matrix factorization (NMF), attracts much attention in the field of signal processing. A matrix with non-negative elements can be decomposed into a product of two matrices with non-negative elements by the NMF. One resulting matrix can be regarded as a basis matrix and the other can be regarded as a coefficient matrix giving linear combinations of the basis vectors. In practical problems, there exists a case where an ideal basis is partially known. In this paper, we propose a novel method for NMF considering given vectors in an ideal basis. We introduce a criterion for the method and construct an algorithm to optimize the criterion. Moreover, we prove that the proposed algorithm surely converges. Some results of computer simulations are also given to verify the efficacy of the proposed method. © 2011 IEEE.
  • Atsushi Takizawa, Akira Tanaka, Masaaki Miyakoshi
    Proceedings - 2011 IEEE International Conference on Granular Computing, GrC 2011 625 - 629 2011年 [査読有り][通常論文]
     
    Self-calibration is one of powerful tools in the field of computer vision such as 3-D shape reconstruction and camera motion reconstruction. Self-calibration consists of two main parts. One is projective reconstruction and the other is metric reconstruction. The latter one can be reduced to a problem to find a matrix that satisfies some absolute dual quadric (ADQ) constraint. However, it is difficult to formulate the problem with considering the constraint strictly, which may make the final result such as reconstructed 3-D shapes unstable. In this paper, we propose a novel method for metric reconstruction incorporating a partial joint diagonalization of symmetric matrices. Some results of computer simulations are also given to verify the efficacy of the proposed method. © 2011 IEEE.
  • Akira Tanaka, Hideyuki Imai, Mineichi Kudo, Masaaki Miyakoshi
    2011 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING 2072 - 2075 2011年 [査読有り][通常論文]
     
    One of central topics of kernel machines in the field of machine learning is a model selection, especially a selection of a kernel or its parameters. In our previous work, we discussed a class of kernels forming a class of nested reproducing kernel Hilbert spaces with an invariant metric; and proved that the kernel corresponding to the smallest reproducing kernel Hilbert space, including an unknown true function, gives the optimal model. In this paper, we consider a class of kernels forming a class of nested reproducing kernel Hilbert spaces whose metrics are not always invariant and show that a similar result to the invariant case is not obtained by providing a counter example using a class of Gaussian kernels.
  • Akira Tanaka, Masaaki Miyakoshi
    2010 IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2010 61 - 66 2011年 [査読有り][通常論文]
     
    Theoretical analyses on generalization error of a model space for kernel regressors with respect to training samples are given in this paper. In general, the distance between an unknown true function and a model space tends to be small with a larger set of training samples. However, it is not clarified that a larger set of training samples achieves a smaller difference at each point of the unknown true function and the orthogonal projection of it onto the model space, compared with a smaller set of training samples. In this paper, we show that the upper bound of the squared difference at each point of these two functions with a larger set of training samples is not larger than that with a smaller set of training samples. We also give some numerical examples to confirm our theoretical result. © 2011 IEEE.
  • 未知観測に対する二次制約を考慮した線形系逆問題
    田中章, 滝沢篤史, 宮腰政明
    第25回SIPシンポジウム講演論文集 A7-1  2010年11月 [査読無し][通常論文]
  • Akira Tanaka, Hideyuki Imai, Masaaki Miyakoshi
    IEEE TRANSACTIONS ON SIGNAL PROCESSING 58 7 3569 - 3577 2010年07月 [査読有り][通常論文]
     
    A perfect reconstruction of functions in a reproducing kernel Hilbert space from a given set of sampling points is discussed. A necessary and sufficient condition for the corresponding reproducing kernel and the given set of sampling points to perfectly recover the functions is obtained in this paper. The key idea of our work is adopting the reproducing kernel Hilbert space corresponding to the Gramian matrix of the kernel and the given set of sampling points as the range space of a sampling operator and considering the orthogonal projector, defined via the range space, onto the closed linear subspace spanned by the kernel functions corresponding to the given sampling points. We also give an error analysis of a reconstructed function by incomplete sampling points.
  • Performance Improvement of Second-Order-Statistics-Based Noisy BSS
    A. Tanaka, M. Miyakoshi
    Proceedings of the 7th IASTED International Conference on Signal Processing, Pattern Recognition and Applications (SPPRA2010) 16 - 21 2010年02月 [査読有り][通常論文]
  • Akira Tanaka, Hideyuki Imai, Mineichi Kudo, Masaaki Miyakoshi
    Proceedings - International Conference on Pattern Recognition 1421 - 1424 2010年 [査読有り][通常論文]
     
    A relationship between generalization error and training samples in kernel regressors is discussed in this paper. The generalization error can be decomposed into two components. One is a distance between an unknown true function and an adopted model space. The other is a distance between an estimated function and the orthogonal projection of the unknown true function onto the model space. In our previous work, we gave a framework to evaluate the first component. In this paper, we theoretically analyze the second one and show that a larger set of training samples usually causes a larger generalization error. © 2010 IEEE.
  • Akira Tanaka, Masaaki Miyakoshi
    2010 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING 2074 - 2077 2010年 [査読有り][通常論文]
     
    One of central topics of kernel machines in the field of machine learning is a model selection, especially a selection of a kernel or its parameters. In our previous work, we discussed a class of kernels whose corresponding reproducing kernel Hilbert spaces have an invariant metric and proved that the kernel corresponding to the smallest reproducing kernel Hilbert space, including an unknown true function, gives the optimal model. However, discussions for properties that make the metrics of reproducing kernel Hilbert spaces invariant are insufficient. In this paper, we show a necessary and sufficient condition that makes the metrics of reproducing kernel Hilbert spaces invariant.
  • Kazuki Tsuji, Mineichi Kudo, Akira Tanaka
    STRUCTURAL, SYNTACTIC, AND STATISTICAL PATTERN RECOGNITION 6218 90 - 99 2010年 [査読有り][通常論文]
     
    It is interesting to compare different criteria of kernel machines. In this paper, the following is made: 1) to cope with the scaling problem of projection learning, we propose a dynamic localized projection learning using k nearest neighbors, 2) the localized method is compared with SVM from some viewpoints, and 3) approximate nearest neighbors are demonstrated their usefulness in such a localization. As a result, it is shown that SVM is superior to projection learning in many classification problems in its optimal setting but the setting is not easy.
  • カーネル法を用いた回帰分析の予測精度について
    今井英幸, 田中章, 池田盛一
    電子情報通信学会技術研究報告, パターン認識・メディア理解 109 344 61 - 64 2009年12月 [査読無し][通常論文]
  • パターン認識における都市伝説
    工藤峰一, 今井英幸, 田中章, 杉山将
    電子情報通信学会技術研究報告, パターン認識・メディア理解 109 344 29 - 34 2009年12月 [査読無し][通常論文]
  • 分離核近似による線形系逆問題の計算量削減
    上野元, 田中章, 宮腰政明
    第24回SIPシンポジウム講演論文集 A1-4  2009年11月 [査読無し][通常論文]
  • 重み付き最小二乗法によるGCDブラインドデコンボリューションの耐雑音性能の向上に関する一考察
    東克憲, 田中章 宮腰政明
    第24回SIPシンポジウム講演論文集 A3-1  2009年11月 [査読無し][通常論文]
  • 再生核ヒルベルト空間における標本化定理」
    田中章, 今井英幸, 宮腰政明
    第24回SIPシンポジウム講演論文集 A1-2  2009年11月 [査読無し][通常論文]
  • 解析型二次統計量ICAとkurtosisに基づく学習区間判定を用いたリアルタイムブラインド音源抽出
    藤原裕樹, 高橋祐, 橘健太郎, 宮部滋樹, 猿渡洋, 鹿野清宏, 田中章
    電子情報通信学会論文誌A J92-A 5 314 - 326 2009年05月 [査読有り][通常論文]
  • Real-time blind source extraction with learning period detection based on closed-form second-order ICA and kurtosis
    Yuuki Fujihara, Yu takahashi, Kentaro Tachibana, Shigeki Miyabe, Hiroshi Saruwatari, Kiyohiro Shikano, Akira Tanaka
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (Japanese Edition) 92-A 5 314 - 326 2009年05月 [査読有り][通常論文]
  • GCD-Based Blind Deconvolution Using PCA-Based Noise Reduction
    A. Tanaka, K. Azuma, M. Miyakoshi
    Proceedings of the 6th IASTED International Confderence on Signal Processing, Pattern Recognition and Applications (SPPRA2009) 89 - 94 2009年02月 [査読有り][通常論文]
  • Hiroshi Saruwatari, Yu Takahashi, Kentaro Tachibana, Yoshimitsu Mori, Shigeki Miyabe, Kiyohiro Shikano, Akira Tanaka
    2009 3RD IEEE INTERNATIONAL WORKSHOP ON COMPUTATIONAL ADVANCES IN MULTI-SENSOR ADAPTIVE PROCESSING (CAMSAP) 249 - 252 2009年 [査読有り][通常論文]
     
    In this paper, we propose a fast and versatile blind source separation including closed-form estimation of sources' probability density functions (PDFs), where the ICA's activation function is automatically adapted to various noise conditions. In the proposed method, closedform second-order ICA and closed-form PDF estimation are introduced as a computational-cost-efficient preprocessing to extract sources' PDFs. Compared with various type of conventional ICAs, e. g., fixed activation-function type and ML-based type, our proposed algorithm can give a faster and higher convergence. Experimental assessment reveals that the proposed method is versatile for handling non-speech sound sources.
  • Akira Tanaka, Masaaki Miyakoshi, Nobutaka Ono
    2009 IEEE/SP 15TH WORKSHOP ON STATISTICAL SIGNAL PROCESSING, VOLS 1 AND 2 421 - + 2009年 [査読有り][通常論文]
     
    Recently, a technique named 'blind decorrelation' was proposed by which we can blindly diagonalize correlation matrices of isotropic noises observed by particular crystal-shape sensor arrays. This technique enables us to estimate the power of unknown target signals, which may improve the performance of inverse filters such as the Wiener filter. It was clarified that several classes of crystal-shape arrays achieve the blind decorrelation; and some necessary conditions imposed on a sensor array to realize the blind decorrelation were revealed. However, we do not have a necessary and sufficient condition for a sensor array to achieve the blind decorrelation. In this paper, we show a necessary and sufficient condition for a sensor array to achieve the blind decorrelation, using a novel matrix analysis scheme named 'symmetric decomposition!
  • Takahashi Yu, Hiroshi Saruwatari, Yuki Fujihara, Kentaro Tachibana, Yoshimitsu Mori, Shigeki Miyabe, Kiyohiro Shikano, Akira Tanaka
    2009 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING, VOLS 1- 8, PROCEEDINGS 3681 - + 2009年 [査読有り][通常論文]
     
    In this paper, we propose a new ICA-based BSS algorithm including estimation of sources' probability density functions (PDFs) to adapt the nonlinear activation function to various noise conditions. In the proposed method, closed-form second-order ICA is introduced as a computational-cost-efficient preprocessing to extract sources' PDFs, which is beneficial for real-time application. Compared with various type of conventional ICAs, e.g., fixed activation-function type and ML-based type, our proposed algorithm can give a faster and higher convergence. Based on the proposed source-adaptive ICA, we show a real-time noise reduction results under diffuse noise environment. Also we can demonstrate our recently developed hands-free robot spoken dialogue system via real-time ICA.
  • Akira Tanaka, Masaaki Miyakoshi
    2009 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING, VOLS 1- 8, PROCEEDINGS 2181 - 2184 2009年 [査読有り][通常論文]
     
    Noise suppression by linear filters for a time series is discussed. We propose a method for jointly estimating signal and noise correlation matrices by incorporating steering vectors of the noise or eigenvectors of the noise correlation matrix as well as steering vectors of the target signals. Our estimates bring us two significant advantages. One is reduction of computational cost in obtaining the Wiener filter since the Wiener post filter, which is combined to the minimum variance distortionless response filter (MVDRF), is no longer needed with the estimates of signal and noise correlation matrices. The other is an improvement of the performance of the MVDRF since we can construct the regularized version of it with an estimate of the noise correlation matrix.
  • Hiroshi Saruwatari, Yu Takahashi, Kentaro Tachibana, Yoshimitsu Mori, Shigeki Miyabe, Kiyohiro Shikano, Akira Tanaka
    2009 3RD IEEE INTERNATIONAL WORKSHOP ON COMPUTATIONAL ADVANCES IN MULTI-SENSOR ADAPTIVE PROCESSING (CAMSAP 2009) 249 - + 2009年 [査読有り][通常論文]
     
    In this paper, we propose a fast and versatile blind source separation including closed-form estimation of sources' probability density functions (PDFs), where the ICA's activation function is automatically adapted to various noise conditions. In the proposed method, closed. form second-order ICA and closed-form PDF estimation are introduced as a computational-cost-efficient preprocessing to extract sources' PDFs. Compared with various type of conventional ICAs, e.g., fixed activation-function type and ML-based type, our proposed algorithm can give a faster and higher convergence. Experimental assessment reveals that the proposed method is versatile for handling non-speech sound sources.
  • 同時対角化行列の摂動解析と二次統計量BSSへの応用
    田中章, 三佐川祐輔, 宮腰政明
    電子情報通信学会論文誌A J91-A 11 1093 - 1097 2008年11月 [査読有り][通常論文]
  • Performance Improvement of Higher-Order ICA Using Learning Period Detection Based on Closed-Form Second-Order ICA and Kurtosis
    Y. Fujihara, Y. Takahashi, S. Miyabe, H. Saruwatari, K. Shikano, A. Tanaka
    Proceedings of the 11th International Workshop for Acoustic Echo and Noise Control (IWAENC2008) 2008年09月 [査読有り][通常論文]
  • Noisy BSS Based on Joint Diagonalization of Differences of Correlation Matrices
    A. Tanaka, H. Imai, M. Miyakoshi
    Proceedings of the 10th IASTED International Conference Signal and Image Processing (SIP 2008) 368 - 373 2008年08月 [査読有り][通常論文]
  • 解析型二次統計量ICAとkurtosisに基づく学習区間判定を用いた高次統計量ICAの高速化
    藤原裕樹, 高橋祐, 宮部滋樹, 猿渡洋, 鹿野清宏, 田中章
    電子情報通信学会技術研究報告, 応用音響 108 68 53 - 58 2008年05月 [査読無し][通常論文]
  • 相関行列差分の同時対角化によるNoisy BSSにおける相関行列選択
    今井雄基, 田中章, 宮腰政明
    電子情報通信学会技術研究報告, 応用音響 107 532 91 - 95 2008年03月 [査読無し][通常論文]
  • Wiener Implementation of Kernel Machines
    A. Tanaka, H. Imai, J. Toyama, M. Kudo, M. Miyakoshi
    Proceedings of the Fifth IASTED International Conference on Signal Processing, Pattern Recognition, and Applications (SPPRA2008) 1 - 6 2008年02月 [査読有り][通常論文]
  • Akira Tanaka, Hideyuki Imai, Mineichi Kudo, Masaaki Miyakoshi
    STRUCTURAL, SYNTACTIC, AND STATISTICAL PATTERN RECOGNITION 5342 530 - 539 2008年 [査読有り][通常論文]
     
    Learning based oil kernel machines is widely known as a, powerful tool for various fields of information science such as pattern recog nition and regression estimation. One of central topics of kernel machines is model selection, especially selection of a kernel or its parameters. In this paper, we consider a. class of kernels that forms a monotonic classes of reproducing kernel Hilbert spaces with an invariant metric and show that the kernel corresponding to the smallest reproducing kernel Hilbert space including an unknown true function gives the optimal model for the unknown true function.
  • Fast Nonclosed-Form Higher-Order ICA with Frequency-Subband Selection Using Closed-Form Second-Order ICA
    K. Tachibana, Y. Takahashi, Y. Mori, H. Saruwatari, K. Shikano, A. Tanaka
    Journal of Signal Processing 12 4 327 - 330 2008年 [査読有り][通常論文]
  • Akira Tanaka, Masaaki Miyakoshi
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E90A 12 2952 - 2956 2007年12月 [査読有り][通常論文]
     
    A parametric linear filter for a linear observation model usually requires a parameter selection process so that the filter achieves a better filtering performance. Generally, criteria for the parameter selection need not only the filtered solution but also the filter itself with each candidate of the parameter. Obtaining the filter usually costs a large amount of calculations. Thus, an efficient algorithm for the parameter selection is required. In this paper, we propose a fast parameter selection algorithm for linear parametric filters that utilizes a joint diagonalization of two non-negative definite Hermitian matrices.
  • Closed-form 2 次統計量 ICA に基づく周波数選択および確率密度関数推定による nonclosed-form 高次統計量 ICA の高速化
    橘健太郎, 高橋祐, Even Jani, 森康充, 宮部滋樹, 猿渡洋, 鹿野清宏, 田中章
    第22回SIPシンポジウム講演論文集 P1-1  2007年11月 [査読無し][通常論文]
  • 音場再現システムにおける最適スピーカー配置に関する一検討
    横関誠, 田中章, 宮腰政明
    第22回SIPシンポジウム講演論文集 B2-2  2007年11月 [査読無し][通常論文]
  • Akira Tanaka, Hideyuki Imai, Mineichi Kudo, Masaaki Miyakoshi
    PATTERN RECOGNITION 40 11 2930 - 2938 2007年11月 [査読有り][通常論文]
     
    Kernel machines are widely considered to be powerful tools in various fields of information science. By using a kernel, an unknown target is represented by a function that belongs to a reproducing kernel Hilbert space (RKHS) corresponding to the kernel. The application area is widened by enlarging the RKHS such that it includes a wide class of functions. In this study, we demonstrate a method to perform this by using parameter integration of a parameterized kernel. Some numerical experiments show that the unresolved problem of finding a good parameter can be neglected. (c) 2007 Pattern Recognition Society. Published by Elsevier Ltd. All rights reserved.
  • 線形推定理論に基づく固有空間BPLP法の改善
    田中章, 宮腰政明
    電子情報通信学会論文誌D J90-D 10 2840 - 2847 2007年10月 [査読有り][通常論文]
  • 高次統計量に基づく混合比推定による Blind-MINT 法の拡張
    田中章, 宮腰政明
    電子情報通信学会技術研究報告, 応用音響 107 120 7 - 12 2007年06月 [査読無し][通常論文]
  • 信号解析に用いられるユニタリー行列の固有解析
    宮腰政明, 田中章, 河口万由香
    電子情報通信学会論文誌A J90-A 5 403 - 414 2007年05月 [査読有り][通常論文]
  • Akira Tanaka, Hideyuki Imai, Masaaki Miyakoshi
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E90A 2 419 - 428 2007年02月 [査読有り][通常論文]
     
    In D.O.A. estimation, identification of the signal and the noise subspaces plays an essential role. This identification process was traditionally achieved by the eigenvalue decomposition (EVD) of the spatial correlation matrix of observations or the generalized eigenvalue decomposition (GEVD) of the spatial correlation matrix of observations with respect to that of an observation noise. The framework based on the GEVD is not always an extension of that based on the EVD, since the GEVD is not applicable to the noise-free case which can be resolved by the framework based on the EVD. Moreover, they are not applicable to the case in which the spatial correlation matrix of the noise is singular. Recently, a quotient-singular-value-decomposition-based framework, that can be applied to problems with singular noise correlation matrices, is introduced for noise reduction. However, this framework also can not treat the noise-free case. Thus, we do not have a unified framework of the identification of these subspaces. In this paper, we show that a unified framework of the identification of these subspaces is realized by the concept of proper and improper eigenspaces of the spatial correlation matrix of the noise with respect to that of observations.
  • Akira Tanaka, Hideyuki Imai, Masaaki Miyakoshi
    2007 IEEE/SP 14TH WORKSHOP ON STATISTICAL SIGNAL PROCESSING, VOLS 1 AND 2 109 - 113 2007年 [査読有り][通常論文]
     
    The aim of blind source separation is to recover mutually independent unknown source signals from observations obtained through an unknown linear mixture system. A simultaneous diagonalization of correlation matrices (second-order statistics) of the observations is a possible resolution for the case when the unknown source signals are non-stationary. In general, unknown source signals are not strictly uncorrelated; this may cause a degradation in the separation performance. In this study, we propose a method for selecting a combination of correlation matrices that yields a better separation performance, and verify the efficacy of the proposed method by computer simulations.
  • Kentaro Tachibana, Hiroshi Saruwatari, Yoshimitsu Mori, Shigeki Miyabe, Kiyohiro Shikano, Akira Tanaka
    2007 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING, VOL I, PTS 1-3, PROCEEDINGS 45 - + 2007年 [査読有り][通常論文]
     
    In this paper, first, we propose a computational-cost efficient blind source separation combining closed-form 2nd-order independent component analysis (ICA) and nonclosed-form higher-order ICA. The closed-form solution of the 2nd-order ICA has been recently presented by one of the authors. This finding motivates us to combine the closed-form 2nd-order ICA and higher-order ICA, where the preceding closed-form ICA produces a good initial value and the following higher-order ICA updates the separation filters from the advantageous status. Secondly, we utilize the proposed architecture to address an essential question that which type of statistics is more beneficial to ICA among non-stationarity and non-Gaussianity. This can be conducted owing to the attractive property that the closed-form ICA can provide a good estimate of the theoretical upper limitation of the separation performance among 2nd-order ICAs without suffering from poor-convergence problems. Experimental results reveal that the non-Gaussianity-based ICA can outperform the nonstationarity-based ICA.
  • Closed-form 2 次統計量 ICA と nonclosed-form 高次統計量ICA を用いたブラインド音源分離
    橘健太郎, 猿渡洋, 森康充, 宮部滋樹, 鹿野清宏, 田中章
    電子情報通信学会技術研究報告, 応用音響 106 432 37 - 42 2006年12月 [査読無し][通常論文]
  • 線形制約の一般解によるパラメトリック部分射影フィルタの解釈とアフィン制約付き復元問題への応用
    田中章, 今井英幸, 宮腰政明
    電子情報通信学会論文誌A J89-A 8 679 - 681 2006年08月 [査読有り][通常論文]
  • Akira Tanaka, Hideyuki Imai, Masaaki Miyakoshi
    2006 IEEE INTERNATIONAL SYMPOSIUM ON SIGNAL PROCESSING AND INFORMATION TECHNOLOGY, VOLS 1 AND 2 647 - + 2006年 [査読有り][通常論文]
     
    The aim of "Blind Source Separation" is to recover mutually independent unknown source signals from observations obtained through an unknown linear mixture system. Simultaneous diagonalization of correlation matrices (second-order statistics) of observations is one of resolutions, when the unknown source signals are non-stationary. When observation noise exists, this method needs to correct the correlation matrices based on an estimation of the variance of the noise. However the estimation of the variance of the noise requires additional information such as redundant observations. In this paper we propose a new method of estimating the variance of the noise without additional information by utilizing a necessary and sufficient condition that simultaneous diagonalization of the correlation matrices is always achieved. We also verify the efficacy of the proposed method by numerical examples.
  • Akira Tanaka, Hideyuki Imai, Masaaki Miyakoshi
    2006 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING, VOLS 1-13 3051 - 3054 2006年 [査読有り][通常論文]
     
    The aim of "Blind Source Separation" is to recover mutually independent unknown source signals from observations obtained through an unknown linear mixture system. Simultaneous diagonalization of correlation matrices (second-order statistics) of observations is one of the resolutions, when the unknown source signals are non-stationary. Although it is trivial that the true separation matrix simultaneously diagonalizes all the correlation matrices, it is not well investigated whether a simultaneous diagonalizer of the correlation matrices is always a separation matrix. In this paper, we give explicit solutions of simultaneous diagonalizers of the correlation matrices and we also clarify the condition that the solutions always achieve the blind source separation.
  • Akira Tanaka, Hideyuki Imai, Mineichi Kudo, Masaaki Miyakoshi
    AIP Conference Proceedings 839 347 - 353 2006年 [査読有り][通常論文]
     
    Learning based on kernel machines is widely known as a powerful tool for various fields of information science. The kernel ridge regression is one of simple and classical kernel machines and it gives a foundation for other kernel machines such as the support vector machine. However, it has some problems such as arbitrariness of the model and theoretical validity of an ad hoc kernelization of the ridge regression. The essence of using a kernel in learning problems is that the unknown target is representable by a function belonging to the reproducing kernel Hilbert space corresponding to the adopted kernel. In this paper, on the basis of the essence, we give two identical interpretations, whose theoretical grounds are clarified, for the kernel ridge regression. One is the ridge regression on the reproducing kernel Hilbert space and the other is the parametric projection learning with a specific condition. © 2006 American Institute of Physics.
  • Akira Tanaka, Masashi Sugiyama, Hideyuki Imai, Mineichi Kudo, Masaaki Miyakoshi
    STRUCTURAL, SYNTACTIC, AND STATISTICAL PATTERN RECOGNITION, PROCEEDINGS 4109 862 - 870 2006年 [査読有り][通常論文]
     
    Learning based on kernel machines is widely known as a powerful tool for various fields of information science such as pattern recognition and regression estimation. The efficacy of the model in kernel machines depends on the distance between the unknown true function and the linear subspace, specified by the training data set, of the reproducing kernel Hilbert space corresponding to an adopted kernel. In this paper, we propose a framework for the model selection of kernel-based learning machines, incorporating a class of kernels with an invariant metric.
  • アフィン制約を考慮した画像復元フィルタの構成
    田中章, 今井英幸, 宮腰政明
    第20回信号処理シンポジウム講演論文集 D7-3  2005年11月 [査読無し][通常論文]
  • Akira Tanaka, Masaaki Miyakoshi
    ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings III III257 - III260 2005年 [査読有り][通常論文]
     
    In this paper, a new method of direction of arrival (D.O.A.) estimation with environmental noise, whose spatial correlation matrix is singular, is proposed. In D.O.A. estimation, identification of signal and noise subspaces plays a very important role. The identification process can be achieved by (generalized) eigenvalue decomposition of the spatial correlation matrix of observations (with respect to that of noise), if these spatial correlation matrices are non-singular. However, these mathematical tools can not be applied to the problems in which the spatial correlation matrices are singular. The main idea of this work deeply depends on identification of proper and improper eigenvectors of the spatial correlation matrix of noise with respect to that of observations. The results of computer simulations are also presented to verify the efficacy of the proposed method. ©2005 IEEE.
  • A Tanaka, H Imai, M Miyakoshi
    Proceedings of the Fifth IASTED International Conference on Visualization, Imaging, and Image Processing 326 - 331 2005年 [査読有り][通常論文]
     
    In image restoration problems, an effective restoration is achieved by a priori, knowledge of the unknown original image. An affine constraint could be considered as such a priori knowledge, which may appear when we know intensities of particular pixels of the unknown original image, for instance. Adopting the least-squares criterion with an affine constraint seems to be one of simple and reasonable approaches. However, it was reported in past studies that some problems may occur with the least squares criterion based methods, even if no constraint is imposed. The family of (parametric) projection filters was proposed as one of resolutions for the problems. However, they do not have a framework to deal with an affine constraint, while a linear constraint can be considered. In this paper, we propose a new restoration filter in which an affine constraint is appropriately considered by extending the (parametric) partial projection filter which belongs to the family of (parametric) projection filters. Numerical examples are also presented to verify the efficacy of the proposed method.
  • A Tanaka, H Imai, M Miyakoshi
    ELECTRONICS AND COMMUNICATIONS IN JAPAN PART II-ELECTRONICS 88 8 54 - 65 2005年 [査読有り][通常論文]
     
    Image restoration is a problem in which an unknown original image is to be estimated from a degraded image obtained from some observation process. Various restoration methods have been proposed. Most of the conventional methods assume that the observation process is regular or almost regular. However, in general there is no guarantee that the observation process is regular, and the restoration performance of past methods is insufficient for a singular observation process. The degradation of restoration performance in a singular observation process arises from the fact that it is difficult to estimate the components related to the null space, which is eliminated in the observation process. There have recently been many studies of the properties and representations of the image signal. In one such study it was reported that the difference signal of the image approximately follows the Laplace distribution. This paper is based on that stochastic property of the image, and proposes a method of restoring images with high precision by positively estimating the image component which is eliminated in a singular observation process. The effectiveness of the proposed method is investigated by numerical experiment. (c) 2005 Wiley Periodicals, Inc.
  • 音場再現システムのための正則化逆フィルタの設計
    田中章, 大谷尚之, 宮腰政明
    電子情報通信学会論文誌A J87-A 11 1466 - 1467 2004年11月 [査読有り][通常論文]
  • A Tanaka, H Imai, M Miyakoshi
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E87A 8 2144 - 2151 2004年08月 [査読有り][通常論文]
     
    In terms of the formulation of the optimality, image restoration filters can be divided into two streams. One is formulated as an optimization problem in which the fidelity of a restored image is indirectly evaluated, and the other is formulated as an optimization problem based on a direct evaluation. Originally, the formulation of the optimality and the solutions derived from the formulation are identical each other. However in many studies adopting the former stream, an arbitrary choice of a solution without a mathematical ground passes unremarked. In this paper, we discuss the relation between the formulation of the optimality and the solution derived from the formulation from a mathematical point of view, and investigate the relation between a direct style formulation and an indirect one. Through these analyses, we show that the both formulations yield the identical filter in practical situations.
  • M Kudo, H Imai, A Tanaka, T Murai
    STRUCTURAL, SYNTACTIC, AND STATISTICAL PATTERN RECOGNITION, PROCEEDINGS 3138 885 - 893 2004年 [査読有り][通常論文]
     
    A novel algorithm for finding the nearest neighbor was proposed. According to the development of modern technology, the demand is increasing in large-scale datasets with a large number of samples and a large number of features. However, almost all sophisticated algorithms proposed so far are effective only in a small number of features, say, up to 10. This is because in a high-dimensional space many pairs of samples share a same distance. Then the naive algorithm outperforms the others. In this study, we considered to utilize a sequential information of distances obtained by the examined training samples. Indeed, a combinatorial information of examined samples was used as bisectors between possible pairs of them. With this algorithm, a query is processed in O(alphabetand) for n samples in a d-dimensional space and for alpha,beta < 1, in expense of a preprocessing time and space in O(n(2)). We examined the performance of the algorithm.
  • A Tanaka, H Imai, M Miyakoshi
    8TH WORLD MULTI-CONFERENCE ON SYSTEMICS, CYBERNETICS AND INFORMATICS, VOL V, PROCEEDINGS V 92 - 96 2004年 [査読有り][通常論文]
     
    A new approach to restore images degraded by observation processes with stochastic variation is proposed. In practice, an observation process must be estimated by some empirical knowledges, since we can not obtain an exact one. A restored image by a, restoration filter based on an estimated observation process could suffer critical damages even if the deviation of the estimated observation process is comparatively small, sincle an image restoration is one of representative ill-posed problems as is well known. In this paper, we formulate the stochastic variation of observation processes and propose a new image restoration method in which the deviation of the observation process is appropriately considered. It is also clarified that our approach is reduced to a, kind of regularization scheme. Some numerical examples are also shown to verify the efficacy of the proposed method.
  • Tetsuya Murai, Yasuo Kudo, Nam Van Huynh, Akira Tanaka, Mineichi Kudo
    IEEE International Conference on Fuzzy Systems 1 263 - 268 2004年 [査読有り][通常論文]
     
    In this paper, firstly, processes of classical inference are reviewed as granular reasoning from a point of view of reconstructing Kripke-style models with granularity. The essential point of the reconstruction is that some possible worlds are amalgamated to generate granules of worlds and vice versa. It is also called zoom reasoning systems. Then, the idea is applied for fuzzy reasoning processes by considering fuzzily granularized possible worlds. There linguistic truth values with linguistic hedges can be naturally introduced.
  • A Tanaka, Takigawa, I, H Imai, M Kudo, M Miyakoshi
    KNOWLEDGE-BASED INTELLIGENT INFORMATION AND ENGINEERING SYSTEMS, PT 1, PROCEEDINGS 3213 1058 - 1064 2004年 [査読有り][通常論文]
     
    Kernel machines are widely known as powerful tools for various fields of information science. In general, they are designed based on a generalization criterion related to the complexity of the model and intuitive but ad hoe philosophy such as maximal margin principle shown in SVM. On the other hand, the project ion learning scheme was proposed in the field of neural networks. In the projection learning, the generalization ability is evaluated by the distance between the unknown target function and the estimated one. In,this paper, we construct projection learning based kernel machines and propose a method of making a kernel function that has necessary representability for the task. The method is reduced to a selection of an appropriate reproducing kernel Hilbert space from a series of monotone increasing subspaces. We also verify the efficacy of the proposed method by numerical examples.
  • Digital Image Enlargement Based on Kernel Component Estimation
    A. Tanaka, H. Imai, M. Miyakoshi
    International Journal of Computing Anticipatory Systems 15 97 - 108 2004年 [査読有り][通常論文]
  • 補空間成分推定に基づく特異観測過程に対する画像復元
    田中章, 今井英幸, 宮腰政明
    電子情報通信学会論文誌D-II Vol.J86-D-II 12 1745 - 1755 2003年12月 [査読有り][通常論文]
  • 線型画像復元問題における定式化と解に関する一考察
    田中章, 今井英幸, 宮腰政明
    第18回DSPシンポジウム講演論文集 D1-1  2003年11月 [査読無し][通常論文]
  • 共役勾配法によるブロック適応フィルタを用いた ANC システム
    藤沢勇希, 田中章, 河口万由香, 宮腰政明
    第18回DSPシンポジウム講演論文集 B5-4  2003年11月 [査読無し][通常論文]
  • Collaborative Filtering using Restoration Operators
    A. Nakamura, M. Kudo, A. Tanaka
    Proceedings of the 7th European Conference on Principles and Practice of Knowledge Discovery in Databases (PKDD2003) 339 - 349 2003年09月 [査読有り][通常論文]
  • 自己回帰・カオス合成モデルによる時系列予測
    安居吉典, 河口万由香, 田中章, 宮腰政明
    電子情報通信学会技術研究報告, 非線形問題 102 625 55 - 60 2003年02月 [査読無し][通常論文]
  • A Nakamura, M Kudo, A Tanaka, K Tanabe
    DISCOVERY SCIENCE, PROCEEDINGS 2843 393 - 401 2003年 [査読有り][通常論文]
     
    We propose a modified version of our collaborative filtering method using restoration operators, which was proposed in [6]. Our previous method was designed so as to minimize expected squared error of predictions for user's ratings, and we experimentally showed that, for users who have evaluated only small number of items, mean squared error of our method is smaller than that of correlation-base methods. After further experiments, however, we found that, for users who have evaluated many items, the best correlation-based method has smaller mean squared error than our method. In our modified version, we incorporated an idea of projecting on a low-dimensional subspace with our method using restoration operators. We experimentally showed that our modification overcame the shortcoming stated above.
  • A Tanaka, H Imai, M Miyakoshi
    PROCEEDINGS OF THE 2003 IEEE WORKSHOP ON STATISTICAL SIGNAL PROCESSING 186 - 189 2003年 [査読有り][通常論文]
     
    A new approach to restore images degraded by singular observation processes is proposed. Existing image restoration filters usually assume non-singularity of observation processes. Therefore, we can not obtain desirable result by these filters, especially in case that the degradation processes have high singularity. By the way, it is well known that differential images can be assumed to be Laplacian distributed random vectors. In this paper, we propose a new restoration method for singular observation processes based on this statistical knowledge about images. A numerical example is also presented to verify the efficacy of the proposed method.
  • A Tanaka, H Imai, M Miyakoshi
    ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE 86 3 77 - 86 2003年 [査読有り][通常論文]
     
    Many of the image restoration techniques can roughly be classified into two types: those that are formulated as an optimization problem with regard to the restored image and those that are formulated as an optimization problem with regard to the restoration operator. The former has the advantage that the local information on the image can easily be expressed in the optimization reference. A problem is that the closeness of the image needs to be evaluated indirectly in the observation image space instead of the original image space. On the other hand, in the latter the closeness of the image can be evaluated in the original image space. However, because the optimization reference used to obtain the appropriate restoration operator does not include the information on the individual images, it is difficult to express the local information on the image, in contrast to the former type. Based on such a background, the objective of this paper is to propose a restoration method that can evaluate the closeness of images in the original image space while the local information on the images can be used systematically, based on improvement of the optimization reference of the parametric projection filter family belonging to the latter. The effectiveness of the proposed method is verified by numerical examples. (C) 2002 Wiley Periodicals, Inc.
  • On Duality of Constrained Least-Squares Restoration and Parametric Wiener Restoration
    田中章, 今井英幸, 宮腰政明
    第17回DSPシンポジウム講演論文集 A2-1  2002年11月 [査読無し][通常論文]
  • On Duality of Formulations in Image Restoration Problems
    A. Tanaka, H. Imai, M. Miyakoshi
    Proceedings of the 4th IASTED International Conference Signal and Image Processing 242 - 247 2002年08月 [査読有り][通常論文]
  • 分離核作用素に対する分離核型正則化一般逆行列
    田中章, 今井英幸, 宮腰政明
    電子情報通信学会論文誌A J85-A 6 730 - 734 2002年06月 [査読有り][通常論文]
  • A Tanaka, H Imai, M Miyakoshi
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E85A 5 1104 - 1110 2002年05月 [査読有り][通常論文]
     
    Practical image restoration filters usually include a parameter that controls regularizability; trade-off between fidelity of a restored image and smoothness of it; and so on. Many criteria for choosing such a parameter have been proposed. However; the relation between these criteria and the squared error of a restored image; which is usually used to evaluate the restoration performance; has not been theoretically substantiated. Sugiyama and Ogawa proposed the subspace information criterion (SIC) for model selection of supervised learning problems and showed that the SIC is an unbiased estimator of the expected squared error between the unknown model function and an estimated one. They also applied it to restoration of images. However, we need an unbiased estimator of the unknown original image to construct the criterion; so it can not be used for general situations. In this paper; we present a modified version of the SIC as a new criterion for choosing a parameter of image restoration filters. Some numerical examples are also shown to verify the efficacy of the proposed criterion.
  • A Tanaka, H Imai, M Miyakoshi
    6TH WORLD MULTICONFERENCE ON SYSTEMICS, CYBERNETICS AND INFORMATICS, VOL XVI, PROCEEDINGS XVI 324 - 325 2002年 [査読有り][通常論文]
     
    In view of formulation, image restoration filters can be divided into two streams. One is formulated as an optimization problem for a image, and the other is for a, restoration operator. The latter is proposed to deal with the lack of strictness in formulation that the former may have. However, the former formulation has been used in many studies without verification of its validity. In this paper, we discuss the relations and differences between these two formulations from a mathematical point of view, and verify the validity of some classical restoration filters.
  • Choosing the Parameter of Regularized MP-Inverses by Modified SIC in Image Restoration Problems
    A. Tanaka, H. Imai, M. Miyakoshi
    International Journal of Computing Anticipatory Systems 12 166 - 178 2002年 [査読有り][通常論文]
  • A Tanaka, H Imai, M Miyakoshi
    ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE 85 11 9 - 17 2002年 [査読有り][通常論文]
     
    In image restoration, if knowledge about the unknown original image could be used, reflecting that knowledge in the restoration process would enable effective restoration. However, in statistical image restoration that employs the family of projection filters or the family of parametric projection filters, the knowledge cannot be information other than information that limits the range in which the original image belongs to a linear subspace and limits the spatial measures to decisions based on the variance structure of the image population. We propose a family of signal-adaptive parametric projection filters that introduces knowledge about the image that should solve this problem in the form of Pareto optimization. In this paper, we construct a family of filters that can reflect knowledge about the image in the spatial measures as a new approach. We also present an example illustrating the construction of the measures and prove the effectiveness of these filters through numerical examples. (C) 2002 Wiley Periodicals, Inc.
  • 線形最適画像復元フィルタに関する一考察
    田中章, 今井英幸, 宮腰政明
    第16回DSPシンポジウム講演論文集 53 - 58 2001年11月 [査読無し][通常論文]
  • M-N-ノルム型パラメトリック射影フィルタ族による画像復元
    田中章, 今井英幸, 宮腰政明
    電子情報通信学会論文誌A J84-A 8 1063 - 1070 2001年08月 [査読有り][通常論文]
  • 重み付きヒルベルト空間上でのパラメトリック射影フィルタ族の構成
    田中章, 今井英幸, 宮腰政明
    第15回DSPシンポジウム講演論文集 581 - 586 2000年11月 [査読無し][通常論文]
  • 信号適応型パラメトリック射影フィルタ族による画像復元
    田中章, 今井英幸, 宮腰政明
    電子情報通信学会論文誌A J83-A 8 1011 - 1020 2000年08月 [査読有り][通常論文]
  • ノルム拘束に基づくパラメトリック射影フィルタ族の正則化
    田中章, 今井英幸, 宮腰政明
    電子情報通信学会論文誌A J83-A 6 812 - 820 2000年06月 [査読有り][通常論文]
  • 階層的適応重みを用いたパラメトリック射影フィルタによる自然画像の復元
    田中章, 宮腰政明
    電子情報通信学会論文誌D-II J83-D-II 2 662 - 670 2000年02月 [査読有り][通常論文]
  • Image restoration by multiscale spatial adaptive regularization
    A. Tanaka, M. Miyakoshi
    International Journal of Computing Anticipatory Systems 6 341 - 353 2000年 [査読有り][通常論文]
  • パラメトリック射影フィルタ族の正則化に関する一考察
    田中章, 今井英幸, 宮腰政明
    第14回DSPシンポジウム講演論文集 210 - 206 1999年11月 [査読無し][通常論文]
  • 射影フィルタ族の分離核表現
    田中章, 宮腰政明
    電子情報通信学会論文誌D-II J82-D-II 4 838 - 840 1999年04月 [査読有り][通常論文]
  • H Imai, A Tanaka, M Miyakoshi
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E82A 3 527 - 534 1999年03月 [査読有り][通常論文]
     
    Optimum filters for an image restoration are formed by a degradation operator, a covariance operator of original images, and one of noise. However, in a practical image restoration problem, the degradation operator and the covariance operators are estimated on the basis of empirical knowledge. Thus, it appears that they differ from the true ones. When we restore a degraded image by an optimum filter belonging to the family of Projection Filters and Parametric Projection Filters, it is shown that small deviations in the degradation operator and the covariance matrix can cause a large deviation in a restored image. In this paper, we propose new optimum filters based on the regularization method called the family of Regularized Projection Filters, and show that they are stable to deviations in operators. Moreover, some numerical examples follow to confirm that our description is valid.
  • 2次形式不等式制約を用いた射影フィルタによる画像復元
    田中章, 今井英幸, 宮腰政明
    電子情報通信学会論文誌D-II J82-D-II 3 415 - 421 1999年03月 [査読有り][通常論文]
  • 多重解像度解析におけるスケール間関係を利用した自然画像の復元
    田中章, 今井英幸, 宮腰政明
    第13回DSPシンポジウム講演論文集 141 - 145 1998年11月 [査読無し][通常論文]
  • H Imai, A Tanaka, M Miyakoshi
    IEEE TRANSACTIONS ON FUZZY SYSTEMS 6 1 90 - 101 1998年02月 [査読有り][通常論文]
     
    In multivariate statistical methods, it is important to identify influential observations for a reasonable interpretation of the data structure, In this paper, we propose a method for identifying influential data in the fuzzy C-means (FCM) algorithm, To investigate such data, we consider a perturbation of the data points and evaluate the effect of a perturbation. As a perturbation, we consider two cases: one is the case in which the direction of a perturbation is specified and the other is the case in which the direction of a perturbation is not specified, By computing the change in the clustering result of FCM when given data points are slightly perturbed, we can look for data points that greatly affect the result, Also, we confirm an efficacy of the proposed method by numerical examples.
  • H Imai, A Tanaka, M Miyakoshi
    IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS E80D 8 788 - 794 1997年08月 [査読有り][通常論文]
     
    A lot of optimum filters have been proposed for an image restoration problem. Parametric filter, such as Parametric Wiener Filter, Parametric Projection Filter, or Parametric Partial Projection Filter, is often used because it requires to calculate a generalized inverse of one operator. These optimum filters are formed by a degradation operator, a covariance operator of noise, and one of original images. In practice, these operators are estimated based on empirical knowledge. Unfortunately it happens that such operators differ from the true ones. In this paper, we show the unified formulae of inducing them to clarify their common properties. Moreover, we investigate their properties for perturbation of a degradation operator. a covariance operator of noise. and one of original images. Some numerical examples follow to confirm that our description is valid.
  • 摂動に対する射影フィルタ族の性質
    今井英幸, 田中章, 宮腰政明
    電子情報通信学会論文誌D-II J80-D-II 5 1128 - 1135 1997年05月 [査読有り][通常論文]
  • 摂動法を用いた最適画像復元フィルタの評価
    今井英幸, 田中章, 宮腰政明
    電子情報通信学会論文誌D-II J80-D-II 3 754 - 761 1997年03月 [査読有り][通常論文]
  • 多重解像度解析を用いたディジタル画像の拡大
    田中章, 今井英幸, 宮腰政明, 伊達惇
    電子情報通信学会論文誌D-II J79-D-II 5 819 - 825 1996年05月 [査読有り][通常論文]

講演・口頭発表等

  • 一般標本化定理における最良近似関数の誤差解析  [通常講演]
    田中章, 宮腰政明
    日本音響学会2010年秋季研究発表会 2010年09月 口頭発表(一般)
  • 再生核ヒルベルト空間に対する標本化定理  [通常講演]
    田中章, 今井英幸, 宮腰政明
    日本音響学会2010年春季研究発表会 2010年03月 口頭発表(一般)
  • 一般標本化定理における最適再生核の数理  [通常講演]
    田中章, 宮腰政明
    日本音響学会2009年春季研究発表会 2009年03月 口頭発表(一般)
  • 相関行列差分に基づく Noisy BSS の有効性に関する一検証  [通常講演]
    今井雄基, 田中章, 宮腰政明
    日本音響学会2008年秋季研究発表会 2008年09月 口頭発表(一般)
  • 等方的雑音共分散行列の対称分解に基づくブラインド無相関化の検討  [通常講演]
    田中和樹, 田中章, 宮腰政明, 小野順貴
    日本音響学会2008年秋季研究発表会 2008年09月 口頭発表(一般)
  • 主成分分析による雑音抑制を用いたGCDに基づくブラインドデコンボリューション  [通常講演]
    東克憲, 田中章, 宮腰政明
    日本音響学会2008年秋季研究発表会 2008年09月 口頭発表(一般)
  • 解析型ICA とkurtosis を利用した音源分離フィルタ学習区間判定における相関行列の選択  [通常講演]
    藤原裕樹, 高橋祐, 宮部滋樹, 猿渡洋, 鹿野清宏, 田中章
    日本音響学会2008年秋季研究発表会 2008年09月 口頭発表(一般)
  • 固有空間BPLP法における固有空間の最適次元について  [通常講演]
    赤平浩規, 田中章, 宮腰政明
    第7回情報科学技術フォーラム 2008年09月 口頭発表(一般)
  • 信号処理に用いられるユニタリ行列と対称群の関係」  [通常講演]
    小野寺慶, 宮腰政明, 田中章, 河口万由香
    電子情報通信学会2008年総合大会 2008年03月 口頭発表(一般)
  • Closed-form 二次統計量ICA と狭帯域 kurtosis を用いたnonclosed-form 高次統計量ICA の学習区間判定  [通常講演]
    藤原裕樹, 高橋祐, 宮部滋樹, 猿渡洋, 鹿野清宏, 田中章
    日本音響学会2008年春季研究発表会 2008年03月 口頭発表(一般)
  • Closed-form 2 次統計量 ICA を利用した確率密度関数推定による nonclosed-form 高次統計量 ICA の高速化  [通常講演]
    橘健太郎, 高橋祐, Even Jani, 森康充, 猿渡洋, 鹿野清宏, 田中章
    日本音響学会2008年春季研究発表会 2008年03月 口頭発表(一般)
  • Closed-form 2 次統計量 ICA と nonclosed-form 高次統計量 ICA を併用した高速ブラインド音源分離の性能評価  [通常講演]
    橘健太郎, 猿渡洋, 森康充, 宮部滋樹, 鹿野清宏, 田中章
    日本音響学会2007年秋季研究発表会 2007年09月 口頭発表(一般)
  • 相関行列差分の同時対角化に基づく Noisy BSS  [通常講演]
    田中章, 宮腰政明
    日本音響学会2007年秋季研究発表会 2007年09月 口頭発表(一般)
  • 相関行列選択に基づく二次統計量 BSS の数理的性質  [通常講演]
    三佐川祐輔, 田中章, 宮腰政明
    日本音響学会2007年秋季研究発表会 2007年09月 口頭発表(一般)
  • Closed-form2 次統計量ICA とnonclosed-form 高次統計量ICA を併用した高速ブラインド音源分離  [通常講演]
    橘健太郎, 猿渡洋, 森康充, 宮部滋樹, 鹿野清宏, 田中章
    日本音響学会2007年春季研究発表会 2007年03月 口頭発表(一般)
  • 二次統計量に基づくBSSにおける相関行列選択  [通常講演]
    田中章, 今井英幸, 宮腰政明
    日本音響学会2007年春季研究発表会 2007年03月 口頭発表(一般)
  • 冗長ウェーブレット変換と射影に基づくノイズシェイピングを用いた動画像圧縮に関する一考察  [通常講演]
    大茂洋岳, 田中章, 河口万由香, 宮腰政明
    第22回ファジィシステムシンポジウム 2006年09月 口頭発表(一般)
  • 二次統計量に基づくBSSのための定常雑音分散推定に関する一考察  [通常講演]
    田中章, 今井英幸, 宮腰政明
    日本音響学会2006年秋季研究発表会 2006年09月 口頭発表(一般)
  • D.O.A.推定における信号・雑音部分空間の数理  [通常講演]
    田中章, 今井英幸, 宮腰政明
    日本音響学会2006年春季研究発表会 2006年03月 口頭発表(一般)
  • 雑音を考慮した Volterra 級数による非線形画像復元  [通常講演]
    木本達也, 田中章, 河口万由香, 宮腰政明
    第4回情報科学技術フォーラム 2005年09月 口頭発表(一般)
  • 冗長なウェーブレット変換を用いた静止画像の雑音除去に関する一考察  [通常講演]
    大茂洋岳, 田中章, 河口万由香, 宮腰政明
    第4回情報科学技術フォーラム, 2005年09月 口頭発表(一般)
  • 時空間特徴を利用した移動物体追跡に関する一考察  [通常講演]
    武田吉史, 田中章, 河口万由香, 宮腰政明
    第4回情報科学技術フォーラム 2005年09月 口頭発表(一般)
  • 凹最小化問題に対する Falk-Soland の分岐限定法に関する一考察  [通常講演]
    斉藤恵一, 施建明, 田中章, 河口万由香, 宮腰政明
    第4回情報科学技術フォーラム 2005年09月 口頭発表(一般)
  • ステレオステージ制御パラメータの決定法に関する考察  [通常講演]
    武晋太郎, 田中章, 河口万由香, 宮腰政明
    第4回情報科学技術フォーラム 2005年09月 口頭発表(一般)
  • 冗長ウェーブレット変換を利用した血管検出  [通常講演]
    大森康宏, 鈴木茂人, 桑村進, 宮腰政明, 河口万由香, 田中章
    第4回情報科学技術フォーラム 2005年09月 口頭発表(一般)
  • 心理音響モデルを用いたオーディオ電子透かし法の改良  [通常講演]
    植村優, 田中章, 河口万由香, 宮腰政明
    第4回情報科学技術フォーラム 2005年09月 口頭発表(一般)
  • 二次統計量に基づくBSSにおける解の解析的表現  [通常講演]
    田中章, 今井英幸, 宮腰政明
    日本音響学会2005年秋季研究発表会 2005年09月 口頭発表(一般)
  • 特異共分散構造を有する雑音環境下における信号・雑音部分空間の特定  [通常講演]
    田中章, 外山淳, 宮腰政明
    日本音響学会2004年秋季研究発表会 2004年09月 口頭発表(一般)
  • 選別した時間領域基底を用いた単一チャネル音源分離  [通常講演]
    門脇亮太, 田中章, 河口万由香, 宮腰政明
    情報処理北海道シンポジウム2004 2004年05月 口頭発表(一般)
  • チェロ奏法におけるビブラート速度と音色評価の評定尺度法による解析  [通常講演]
    木敦之, 田中章, 河口万由香, 宮腰政明
    情報処理北海道シンポジウム2004 2004年05月 口頭発表(一般)
  • Bark尺度に適合したウェーブレット・パケット帯域分割に基づく音響信号圧縮  [通常講演]
    大橋亮, 田中章, 河口万由香, 宮腰政明
    情報処理北海道シンポジウム2004 2004年05月 口頭発表(一般)
  • 並列構成二重くし型フィルタを用いた音程修復  [通常講演]
    小峰規行, 田中章, 河口万由香, 宮腰政明
    情報処理北海道シンポジウム2004 2004年05月 口頭発表(一般)
  • Undecimated ウェーブレット変換と Directional Filter Bank による画像の雑音除去  [通常講演]
    大茂洋岳, 田中章, 河口万由香, 宮腰政明
    情報処理北海道シンポジウム2004 2004年05月 口頭発表(一般)
  • 混合信号ヒストグラムによる適応分布推定に基づく独立成分分析  [通常講演]
    斉藤優樹, 田中章, 宮腰政明
    日本音響学会2003年秋期研究発表会 2003年09月 口頭発表(一般)
  • 混合信号分布の局所近似を用いた独立成分分析  [通常講演]
    斉藤優樹, 田中章, 河口万由香, 宮腰政明
    情報処理北海道シンポジウム2003 2003年04月 口頭発表(一般)
  • 仮想誤差法を用いた ANC システムの計算量低減  [通常講演]
    藤沢勇希, 田中章, 河口万由香, 宮腰政明
    情報処理北海道シンポジウム2003 2003年04月 口頭発表(一般)
  • 多チャンネル音場制御における正則化係数の選択  [通常講演]
    大谷尚之, 田中章, 河口万由香, 宮腰政明
    情報処理北海道シンポジウム2003 2003年04月 口頭発表(一般)
  • 独立性指標を用いた Blind-MINT法の受音点配置制限の緩和  [通常講演]
    川尻崇文, 田中章, 河口万由香, 宮腰政明
    情報処理北海道シンポジウム2003 2003年04月 口頭発表(一般)
  • The Role of Small Irrationarity in Communication and Strategic Decisions: An Example with the Electronic Mail Game  [通常講演]
    K. Takamiya, A. Tanaka
    Taj-IBM Conference on Game Theory & its Applications (Game Theory-2003) 2003年01月 口頭発表(一般)
  • 時系列予測における自己回帰・カオス混合モデル  [通常講演]
    安居吉典, 河口万由香, 田中章, 宮腰政明
    平成14年度電気関係学会北海道支部連合大会 2002年10月 口頭発表(一般)
  • 周波数成分の重なりを用いた音源同定における適応処理の改善  [通常講演]
    土田慎也, 田中章, 宮腰政明
    情報処理北海道シンポジウム2002 2002年04月 口頭発表(一般)
  • Blind-MINT法における受音点配置制限の緩和  [通常講演]
    川尻崇文, 田中章, 宮腰政明
    情報処理北海道シンポジウム2002 2002年04月 口頭発表(一般)
  • 混合信号分布推定に基づく学習則を用いた独立成分分析  [通常講演]
    斉藤優樹, 田中章, 宮腰政明
    情報処理北海道シンポジウム2002 2002年04月 口頭発表(一般)
  • ノイズの影響を考慮した多チャンネル音場制御システム  [通常講演]
    大谷尚之, 田中章, 宮腰政明
    情報処理北海道シンポジウム2002 2002年04月 口頭発表(一般)
  • 2次経路の推定を用いたアクティブノイズコントロールシステム  [通常講演]
    藤沢勇希, 田中章, 宮腰政明
    情報処理北海道シンポジウム2002 2002年04月 口頭発表(一般)
  • ウェーブレット変換係数の特性を利用した自然画像の復元  [通常講演]
    田中章, 今井英幸, 宮腰政明
    情報処理北海道シンポジウム'98, 1998年05月 口頭発表(一般)
  • 非線形エルゴード定理の画像復元への適用  [通常講演]
    中田靖久, 田中章, 今井英幸, 河口万由香, 宮腰政明
    情報処理北海道シンポジウム'96 1996年04月 口頭発表(一般)
  • 多重解像度解析を用いたディジタル画像拡大手法の有効性に関する一検証  [通常講演]
    田中章, 今井英幸, 宮腰政明
    平成7年度電気関係学会北海道支部連合大会 1995年10月 口頭発表(一般)
  • 多重解像度解析を用いた画像の拡大  [通常講演]
    田中章, 今井英幸, 宮腰政明, 伊達惇
    1995年電子情報通信学会総合大会 1995年03月 口頭発表(一般)
  • コンピュータグラフィックスを用いた4次元空間上物体の可視化技法について  [通常講演]
    田中章, 今井英幸, 宮腰政明, 伊達惇
    情報処理北海道シンポジウム'94 1994年04月 口頭発表(一般)

その他活動・業績

  • 安井拓未, 中村篤祥, 中村篤祥, 田中章, 田中章, 工藤峰一, 工藤峰一 情報処理学会研究報告(Web) 2017 (MUS-116) Vol.2017‐MUS‐116,No.15,1‐4 (WEB ONLY) 2017年08月17日 [査読無し][通常論文]
  • Another Interpretation of the Parametric Partial Projection Filter Based on the General Solution of Linear Constraints and Its Application to Restoration with Affine Constraints
    IEICE Transactions A J89-A (8) 679 -681 2006年 [査読無し][通常論文]
  • Hideyuki Imai, Akira Tanaka, Masaaki Miyakoshi Systems and Computers in Japan 28 (8) 25 -32 1997年 [査読無し][通常論文]
     
    The image restoration problem may be considered in the framework of Hilbert space. In such a framework, the optimal restoration filter is made of a degradation operator and a covariance operator of noise. In practice, the degradation operator is determined by experimental knowledge. Unfortunately, it happens that such a degradation operator differs from the true one. Thus, the discrepancy between these operators has essential effects on the restored image. In this paper, confining ourselves to a real-valued finite-dimensional space, we present a method of evaluating how the optimal restoration filter is affected by perturbation of a degradation operator. Some numerical examples follow to confirm that our description is valid. © 1997 Scripta Technica, Inc.

特許

  • 特許第4660773号:信号到来方向推定装置、信号到来方向推定方法、および信号到来方向推定用プログラム  
    7,436,358

受賞

  • 2005年 CASYS'05 Best Paper Award
  • 1996年 電子情報通信学会北海道支部奨励賞

共同研究・競争的資金等の研究課題

  • 機械学習のための再生核の生成と選択
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2020年04月 -2025年03月 
    代表者 : 田中 章
  • マルチカーネル学習の新展開
    研究期間 : 2016年 -2018年 
    代表者 : 田中 章
  • 再生核ヒルベルト空間における標本化定理の数理
    研究期間 : 2012年 -2014年 
    代表者 : 田中 章
  • 標本化と最適再生核の数理
    研究期間 : 2009年 -2011年 
    代表者 : 田中 章
  • 再生核ヒルベルト空間と機械学習の数理
    研究期間 : 2006年 -2008年 
    代表者 : 田中 章
  • Clifford代数を用いた画像処理・復元に関する基礎的研究
    研究期間 : 2005年 -2007年 
    代表者 : 宮腰 政明
  • Sampling theory based on reproducing kernel Hilbert spaces
    研究期間 : 2006年
  • 線形系逆問題の定式化と解の数理
    研究期間 : 2004年 -2005年 
    代表者 : 田中 章
  • 情報通信インターフェースとしてユビキタスパターン認識
    研究期間 : 2003年 -2005年 
    代表者 : 工藤 峰一
  • 大規模パターン認識問題に対する識別系の開発と応用
    研究期間 : 2002年 -2005年 
    代表者 : 工藤 峰一
  • Reproducing kernel Hilbert space for machine learning
    研究期間 : 2003年
  • Mathematical properties of "Blind Source Separtion"
    研究期間 : 2003年
  • 正則化パラメトリック射影フィルタ族の構築に関する研究
    研究期間 : 2001年 -2002年 
    代表者 : 宮腰 政明
  • 人間の視覚特性を考慮した画像復元手法の開発
    研究期間 : 2001年 -2002年 
    代表者 : 田中 章
  • Image restoration
    研究期間 : 2000年

教育活動情報

主要な担当授業

  • 情報理工学特別演習
    開講年度 : 2018年
    課程区分 : 修士課程
    開講学部 : 情報科学研究科
  • 情報数理学特論
    開講年度 : 2018年
    課程区分 : 修士課程
    開講学部 : 情報科学研究科
    キーワード : 束論、多値論理、関係方程式、近似・補間推論、クロネッカー積、微分演算、ヤコビ行列、ヘッセ行列
  • 情報理工学特別講義
    開講年度 : 2018年
    課程区分 : 修士課程
    開講学部 : 情報科学研究科
  • 情報数理学特論
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 情報科学研究科
    キーワード : 束論、多値論理、関係方程式、近似・補間推論、クロネッカー積、微分演算、ヤコビ行列、ヘッセ行列
  • 情報理工学特別研究
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 情報科学研究科
  • 情報理工学演習Ⅲ
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : データ構造,アルゴリズム,ソート,再帰,音声音響信号処理,画像信号処理,画像認識,コンピュータグラフィクス
  • 卒業論文
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 工学部
  • 情報理工学実験Ⅱ
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : データベース、Web、機械学習、並列プログラミング
  • コンピュータサイエンス実験Ⅱ
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : データベース、Web、機械学習、並列プログラミング
  • インターンシップⅠ
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 創造的人材育成、実践的人材育成、就業体験、国内外インターンシップ
  • インターンシップⅡ
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 創造的人材育成、実践的人材育成、就業体験、国内外インターンシップ
  • インタフェース工学
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 音声音響信号処理,画像信号処理,画像認識,コンピュータグラフィクス
  • メディア処理工学
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 音声音響信号処理,画像信号処理,画像認識,コンピュータグラフィクス
  • 科学技術英語演習
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 英語読解力,英語作文力,科学技術英語表現
  • 情報解析学
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 音声音響信号処理,画像信号処理,画像認識,コンピュータグラフィクス
  • 情報解析学演習
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 行列、ベクトル空間、固有値・固有ベクトル、射影行列、一般逆行列
  • 情報理工学入門
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 情報理工学、知識ソフトウェア、自律系工学、調和系工学、ヒューマンコンピュータインタラクション、知識メディア、知識ベース、情報知識ネットワーク、アルゴリズム、情報数理学、情報認識学、知能情報学、情報解析学、超高速計算機網工学、情報システム設計学、先端ネットワーク、先端データ科学

大学運営

委員歴

  • 2013年05月 - 現在   電子情報通信学会   ソサイエティ論文誌編集委員会 査読委員
  • 2011年05月 - 現在   電子情報通信学会   信号処理研究専門委員会 専門委員
  • 2008年05月 - 2014年06月   電子情報通信学会   応用音響研究専門委員会 専門委員   電子情報通信学会
  • 2012年05月 - 2014年05月   日本音響学会   電気音響研究委員会 委員
  • 2009年05月 - 2013年05月   電子情報通信学会   英文論文誌A 編集委員   電子情報通信学会


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