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Yasuo Matsuyama

dblp:86/188 · DBLP profile ↗
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37ranked-venue papers
26as first author
0since 2021 · last 2019
0000-0002-0819-9240ORCID · corroborated

Domains — the database's venue-derived domains; a paper can count in several

Artificial intelligence and machine learning · 29 · 18 first-authorGraphics, computer vision, multimedia, augmented reality and games · 3 · 3 first-authorTheory of computation · 3 · 3 first-authorComputer networks · 1 · 1 first-authorHuman-computer interaction and ubiquitous computing · 1 · 1 first-authorApplied, interdisciplinary, general and emerging computing · 1 · 1 first-author

Expertise — from the expertise taxonomy: the topics of the expert's papers under the CCF categories. A weight counts papers with recency: 1 for a paper about the topic, 0.3 when the topic is its context, halved every five years.

Human-computer interaction and pervasive computing
1 paper
Human-robot interaction · 91% Wearable and physiological sensing · 9%
Artificial intelligence
1 paper
Probabilistic and Bayesian machine learning · 100%
Theoretical computer science
3 papers
Information theory · 65% Coding theory · 35%

Topics — the 13 heaviest of 14, each with the papers that count most for it

TopicWeightPapersLastEvidence papers
Human-robot interaction › healthcare robotics
assistive and rehabilitation robotics
0.112010
Multimodal human-humanoid interaction using motions, brain nirs and spike trains · HRI 2010
Human-robot interaction › physical human-robot interaction
prosthetic control
0.112010
Multimodal human-humanoid interaction using motions, brain nirs and spike trains · HRI 2010
Machine learning › Probabilistic and Bayesian machine learning › statistical inference › parameter estimation
expectation-maximization
0.012003
The alpha-EM algorithm: surrogate likelihood maximization using alpha-logarithmic information measures · IEEE Trans. Inf. Theory 2003
Wearable and physiological sensing
brain-computer interface
0.012010
Multimodal human-humanoid interaction using motions, brain nirs and spike trains · HRI 2010
Information theory
information measures
0.012003
The alpha-EM algorithm: surrogate likelihood maximization using alpha-logarithmic information measures · IEEE Trans. Inf. Theory 2003
Coding theory
source coding
0.021981
Universal tree encoding for speech · IEEE Trans. Inf. Theory 1981
Mismatch Robustness of Linear Prediction and Its Relationship to Coding · Inf. Control. 1980
Content delivery and video streaming › source coding
speech coding
0.011982
Voice Coding and Tree Encoding Speech Compression Systems Based Upon Inverse Filter Matching · IEEE Trans. Commun. 1982
Physical-layer communications › channel coding
tree encoding
0.011982
Voice Coding and Tree Encoding Speech Compression Systems Based Upon Inverse Filter Matching · IEEE Trans. Commun. 1982
Coding theory › source coding
tree coding
0.011981
Universal tree encoding for speech · IEEE Trans. Inf. Theory 1981
Coding theory › source coding
universal coding
0.011981
Universal tree encoding for speech · IEEE Trans. Inf. Theory 1981
Information theory › signal processing › signal prediction
linear prediction
0.011980
Mismatch Robustness of Linear Prediction and Its Relationship to Coding · Inf. Control. 1980
Audio and music processing › speech coding
linear predictive coding
0.011981
Universal tree encoding for speech · IEEE Trans. Inf. Theory 1981
Audio and music processing
speech coding
0.011981
Universal tree encoding for speech · IEEE Trans. Inf. Theory 1981

Methods — techniques the papers use, named apart from their topics

support vector machine · 0.1hidden markov model · 0.1bayesian network · 0.1surrogate likelihood maximization · 0.1convex divergence · 0.1linear predictive coding · 0.0fake process tree encoding · 0.0vector quantization · 0.0mismatch analysis · 0.0inverse filter matching · 0.0
YearPublicationVenuePosition
2019 Divergence Family Attains Blockchain Applications via α-EM Algorithm
abstract
We present a path starting from generalized information measures to blockchain applications. In the middle of these two endpoints, we derive the alpha-EM algorithm and the traditional log-EM algorithm simultaneously from a sole divergence. Thus, there are three subjects. The first part discusses the relationship between the Bregman divergence and the probabilistic alpha-divergence. There, a new alpha-divergence is derived from the Bregman divergence by skewing the probability space. In the second part, both the alpha-EM algorithm and the traditional log-EM algorithm are derived simultaneously from this single divergence. The third part is on the applications to the blockchain. The EM families are effective in statistical machine learning that can be incorporated in miners of blockchains for evaluating the data sent from clients. Any miner appreciates the speed in order to contest with other miners. The alpha-EM matches this purpose because of its faster speed than the log-EM. As a concrete application, we present the wine sommelier evaluation. This formulation using the multinomial mixture distribution can be applicable to a wider class of IoT data that fly on the network.
Yasuo Matsuyama
ISIT1
2016 Verification of fraudulent PIN holders by brain waves
abstract
Brain waves, or electroencephalograms (EEGs), are applicable to user verification. We devise a two-factor system so that impersonators who hold identification numbers in fraudulence are detectable. In the first step, a subject either authentic or false tries to input a digit of a ten-key in the personal identification number by a P300 speller. The P300 speller is a brain-computer interface that detects positive voltage jump when a subject identifies specific digits on a display visually. By considering the performance of the P300 speller, we allow an error of one digit out of the four digits. On the other hand, we keep suspicion even for the case of perfect four digits because of the possibility of impersonation by a stolen case. Following the P300 spelling, we apply a verification of subjects by brain waves. Averaging of detected P300 waveforms after band-pass filtering takes the role of feature extraction. Then, a support vector machine applied to the averaged waveforms decides whether the subject is authentic or false. Thus, the total system does not entail the complexity of multimodality. For this system, we measured average error rates for 20 subjects. Experiments showed the false rejection rate of 3.9% at the false acceptance rate of 0% for the 4-digit number case. These pair values are successfully low even by using brain waves that usually contain many artifacts. Additionally, experiments on a diabetes patient before and after an insulin injection are also conducted. The result shows that the appropriate injection control maintains no difference from ordinary subjects. In concluding remarks, we consider methods to increase subjects and digits for applications in a larger society.
Hiromichi Iwase, Teruki Horie, Yasuo Matsuyama
IJCNN3
2015 Learning Algorithms and Frame Signatures for Video Similarity Ranking
Teruki Horie, Akihiro Shikano, Hiromichi Iwase, Yasuo Matsuyama
ICONIP (1)4
2015 Order-aware exemplars for structuring video sets: Clustering, aligned matching and retrieval by similarity
abstract
Video data captured and uploaded under volatile conditions is accumulating into a flood of unstructured content that is hard to manage. In this paper, we present a set of algorithms that generate numeric or soft labels to structure automatically and produce video similarity rankings. Exemplar frames are extracted from each video during the labeling process. We propose five types of learning algorithms based on the following three classes: affinity propagation, k-means or harmonic competition, and pairwise nearest-neighbor. For redundancy reduction, we also provide an algorithm that prunes excessive exemplars. The five learning algorithms produced creditable order-aware exemplar sets for the target videos. Because the content and lengths of the videos differ in terms of temporal order, we provide new methods to analyze the similarities between exemplar sets. The m-distance similarity measure is the core concept used for the global and local alignments performed on the obtained exemplar sets. Based on this comparison mechanism, we identified high-precision recall curves for all five methods. In terms of learning speed, the k-means and pairwise nearest-neighbor classes are recommendable. To facilitate similar-video retrieval, we developed a graphical user interface that accepts videos downloaded from the Web. By replacing a procedure in the software, the proposed similar-video retrieval system can accommodate more elaborate frame comparison features.
Yasuo Matsuyama, Akihiro Shikano, Hiromichi Iwase, Teruki Horie
IJCNN1
2015 Brain signal's low-frequency fits the continuous authentication
Yasuo Matsuyama, Michitaro Shozawa, Ryota Yokote
Neurocomputing1
2014 Similar-Video Retrieval via Learned Exemplars and Time-Warped Alignment
Teruki Horie, Masafumi Moriwaki, Ryota Yokote, Shota Ninomiya, Akihiro Shikano, Yasuo Matsuyama
ICONIP (3)6
2012 Composite Data Mapping for Spherical GUI Design: Clustering of Must-Watch and No-Need TV Programs
Masaya Maejima, Ryota Yokote, Yasuo Matsuyama
ICONIP (5)3
2011 Hidden Markov model estimation based on alpha-EM algorithm: Discrete and continuous alpha-HMMs
abstract
Fast estimation algorithms for Hidden Markov models (HMMs) for given data are presented. These algorithms start from the alpha-EM algorithm which includes the traditional log-EM as its proper subset. Since existing or traditional HMMs are the outcome of the log-EM, it had been expected that the alpha-HMM would exist. In this paper, it is shown that this foresight is true by using methods of the iteration index shift and likelihood ratio expansion. In each iteration, new update equations utilize one-step past terms which are computed and stored during the previous maximization step. Therefore, iteration speedup directly appears as that of CPU time. Since the new method is theoretically based on the alpha-EM, all of its properties are inherited. There are eight types of alpha-HMMs derived. They are discrete, continuous, semi-continuous and discrete-continuous alpha-HMMs, and both for single and multiple sequences. Using the properties of the alpha-EM algorithm, the speedup property is theoretically analyzed. Experimental results including real world data are given.
Yasuo Matsuyama
IJCNN1
2011 Independent component analysis with graphical correlation: Applications to multi-vision coding
abstract
New algorithms for joint learning of independent component analysis and graphical high-order correlation (GC-ICA: Graphically Correlated ICA) are presented. The presented method has a fixed point style or of the FastICA, however, it comprises independent but correlated subparts. Correlations by teacher signals are also allowed. In spite of such inclusion of the dependency, the presented algorithm shows fast convergence. The converged set of bases has reduced indeterminacy on the ordering. This is equivalent to a self-organization of bases. This method can be used to analyze multiple images simultaneously. Examples are given on images from 3D- stereo videos shots. The correlation of bases on left and right eye views is shown for the first time here. Further speedup using the strategy of the RapidICA is possible.
Ryota Yokote, Toshikazu Nakamura, Yasuo Matsuyama
IJCNN3
2010 Multimodal human-humanoid interaction using motions, brain nirs and spike trains
abstract
Heterogeneous bio-signals including human motions, brain NIRS and neural spike trains are utilized for operating biped humanoids. The Bayesian network comprising Hidden Markov Models and Support Vector Machines is designed for the signal integration. By this method, the system complexity is reduced so that that total operation is within the scope of PCs. The designed system is capable of transducing original sensory meaning to another. This leads to prosthesis, rehabilitation and gaming. In addition to the supervised mode, the humanoid can act autonomously for its own designed tasks.
Yasuo Matsuyama, Nimiko Ochiai, Takashi Hatakeyama, Keita Noguchi
HRI1
2010 Alpha-EM gives fast Hidden Markov Model estimation: Derivation and evaluation of alpha-HMM
abstract
A fast learning algorithm for Hidden Markov Models is derived starting from convex divergence optimization. This method utilizes the alpha-logarithm as a surrogate function for the traditional logarithm to process the likelihood ratio. This enables the utilization of a stronger curvature than the logarithm. This paper's method includes the ordinary Baum-Welch re-estimation algorithm as a proper subset. The presented algorithm shows fast learning by utilizing time-shifted information during the progress of iterations. The computational complexity of this algorithm, which directly affects the CPU time, remains almost the same as the logarithmic one since only stored results are utilized for the speedup. Software implementation and speed are examined in the test data. The results showed that the presented method is creditable.
Yasuo Matsuyama, Ryunosuke Hayashi
IJCNN1
2010 Yet Rapid ICA: Applications to un-indexed image-to-image retrieval
abstract
A faster algorithm of ICA is devised. This method utilizes multi-step past information with the existing fixed-point method. The use of past information comes from the idea of surrogate optimization. The speed and implemented software are checked for both simulated and read data. The presented ICA, named Rapid ICA, is applied to image-to-image retrieval without indices. Images judged to be similar reflected user's opinion well.
Ryota Yokote, Yasuo Matsuyama
IJCNN2
2009 Multimodal Belief Integration by HMM/SVM-Embedded Bayesian Network: Applications to Ambulating PC Operation by Body Motions and Brain Signals
Yasuo Matsuyama, Fumiya Matsushima, Youichi Nishida, Takashi Hatakeyama, Nimiko Ochiai, Shogo Aida
ICANN (1)1
2008 Sensibility-Aware Image Retrieval Using Computationally Learned Bases: RIM, JPG, J2K, and Their Mixtures
Takatoshi Kato, Shun'ichi Honma, Yasuo Matsuyama, Tetsuma Yoshino, Yuuki Hoshino
ICONIP (1)3
2008 Bio-signal Integration for Humanoid Operation: Gesture and Brain Signal Recognition by HMM/SVM-Embedded BN
Yasuo Matsuyama, Fumiya Matsushima, Youichi Nishida, Takashi Hatakeyama, Koji Sawada, Takatoshi Kato
ICONIP (1)1
2008 Protein Folding Classification by Committee SVM Array
Mika Takata, Yasuo Matsuyama
ICONIP (2)2
2007 Image-to-Image Retrieval Using Computationally Learned Bases and Color Information
abstract
New methods for joint compression and Image-to-image retrieval (12I retrieval) are presented. The novelty exists in the usage of computationally learned image bases besides color distributions. The bases are obtained by the Principal Component Analysis and/or the Independent Component Analysis. On the image compression, PCA and ICA outperform the JPEG's DCT This superiority holds even if the bases and superposition coefficients are quantized and encoded. On the 12I retrieval, the precision-recall curve is used to measure the performance. It is found that adding the basis information always increases the baseline ability of the color information. Besides the retrieval evaluation, a unified image format called RIM (Retrieval-aware IMage format) for effective packing of codewords including bases is specified. Furthermore, an image search viewer called Wisvi (Waseda Image Search Viewer) is developed and exploited. A beta-version of all source codes can be down-loaded from a web site given in the text.
Yasuo Matsuyama, Fuminori Ohashi, Fumiaki Horiike, Tomohiro Nakamura, Shun'ichi Honma, Naoto Katsumata, Yuuki Hoshino
IJCNN1
2006 Retrieval-Aware Image Compression, Its Format and Viewer Based Upon Learned Bases
Naoto Katsumata, Yasuo Matsuyama, Takeshi Chikagawa, Fuminori Ohashi, Fumiaki Horiike, Shun'ichi Honma, Tomohiro Nakamura
ICONIP (2)2
2005 Similar-image retrieval systems using ICA and PCA bases
abstract
Similar-image retrieval systems are presented and evaluated. The new systems directly use image bases via ICA (independent component analysis) and PCA (principal component analysis). These bases can extract source image's information which is viable to define similarity measures. But, the indeterminacy on amplitude and permutation exists. In this paper, similarity measures which can absorb such indeterminacy are presented. Then, carefully designed opinion tests are carried out to compare the new systems' ability with existing ones. The compatibility of color spaces such as RGB, YIQ, and HSV is also examined. By these massive tests, {ICA, HSV} is judged the best. The resulting system is thus proved to be highly competent at the similar-image retrieval.
Naoto Katsumata, Yasuo Matsuyama
IJCNN2
2005 Database retrieval for similar images using ICA and PCA bases
Naoto Katsumata, Yasuo Matsuyama
Eng. Appl. Artif. Intell.2
2004 Towards the Unification of Human Movement, Animation and Humanoid in the Network
Yasuo Matsuyama, Satoshi Yoshinaga, Hirofumi Okuda, Keisuke Fukumoto, Satoshi Nagatsuma, Kazuya Tanikawa, Hiroto Hakui, Ryusuke Okuhara, Naoto Katsumata
ICONIP1
2004 ICA photographic encoding gear: image bases towards IPEG
abstract
Independent component analysis (ICA) is applied to image coding. There, new design methods for ICA bases are presented. The new feature of this learning algorithm includes the weak guidance, or decreasing supervisory information. The weak guidance reduces the permutation indeterminacy which is unavoidable in usual ICA algorithms. In view of the image compression, this effect corresponds to the generation of image bases honoring the space frequency's neighborhood and 2-D ordering. Following the presentation of this learning algorithm, experiments are performed to obtain serviceable ICA bases. Finally, image compression and restoration are demonstrated to show the eligibility for "image. IPEG." Other applications such as image retrieval are also commented upon.
Yasuo Matsuyama, Hiroaki Kataoka, Naoto Katsumata, Keita Shimoda
IJCNN1
2003 Independent Component Analysis Minimizing Convex Divergence
Yasuo Matsuyama, Naoto Katsumata, Ryo Kawamura
ICANN1
2003 The alpha-EM algorithm: surrogate likelihood maximization using alpha-logarithmic information measures
abstract
A new likelihood maximization algorithm called the /spl alpha/-EM algorithm (/spl alpha/-expectation-maximization algorithm) is presented. This algorithm outperforms the traditional or logarithmic EM algorithm in terms of convergence speed for an appropriate range of the design parameter /spl alpha/. The log-EM algorithm is a special case corresponding to /spl alpha/=-1. The main idea behind the /spl alpha/-EM algorithm is to search for an effective surrogate function or a minorizer for the maximization of the observed data's likelihood ratio. The surrogate function adopted in this paper is based upon the /spl alpha/-logarithm which is related to the convex divergence. The convergence speed of the /spl alpha/-EM algorithm is theoretically analyzed through /spl alpha/-dependent update matrices and illustrated by numerical simulations. Finally, general guidelines for using the /spl alpha/-logarithmic methods are given. The choice of alternative surrogate functions is also discussed.
Yasuo Matsuyama
IEEE Trans. Inf. Theory1
2000 The α-EM algorithm and its applications
abstract
The /spl alpha/-EM algorithm is a super-class of the traditional expectation-maximization (EM) algorithm. This algorithm is derived by computing the likelihood ratio of incomplete data through an extended logarithm; namely, the /spl alpha/-logarithm. The case of /spl alpha/=-1 corresponds to the logarithm. The number /spl alpha/ adjusts eigenvalues of update matrices by reflecting the optimization function's second-order properties with respect to the estimation parameter. This property shows merits on speedup of convergence. In the paper, a derivation of the algorithm is given first. Then, convergence and speedup properties are discussed. Finally, the applicability of the /spl alpha/-FM algorithm and examples are shown.
Yasuo Matsuyama
ICASSP1
2000 EM Algorithm and -ICA Learning Based upon Extended Logarithmic Information Measures
abstract
The /spl alpha/-logarithm extends the logarithm as the special case of /spl alpha/=-1. Usage of /spl alpha/-related information measures based upon this extended logarithm is expected to be effective to speedup of convergence, i.e., on the improvement of learning aptitude. In this paper, two typical cases are investigated. One is the /spl alpha/-EM algorithm (/spl alpha/-expectation-maximization algorithm) which is derived from the /spl alpha/-log-likelihood ratio. The other is the /spl alpha/-ICA (/spl alpha/-independent component analysis) which is formulated as minimizing the /spl alpha/-mutual information. In the derivation of both algorithms, the /spl alpha/-divergence plays the main role. For the /spl alpha/-EM algorithm, the reason for the speedup is explained using Hessian and Jacobian matrices for learning. For the /spl alpha/-ICA learning, methods of exploiting the past and future information are presented. Examples are shown on single-loop /spl alpha/-EM and sample-based /spl alpha/-ICA. In all cases, effective speedups are observed. Thus, this paper's examples together with formerly reported ones are evidences that the speed improvement by the /spl alpha/-logarithm is a general property beyond individual problems.
Yasuo Matsuyama, Takeshi Niimoto, Naoto Katsumata, Yoshitaka Suzuki, Satoshi Furukawa
IJCNN (3)1
1999 The α-EM learning and its cookbook: from mixture-of-expert neural networks to movie random field
abstract
The /spl alpha/-EM algorithm is a proper extension of the traditional log-EM algorithm. This new algorithm is based on the /spl alpha/-logarithm, while the traditional one uses the logarithm. The case of /spl alpha/=-1 corresponds to the log-EM algorithm. Since the speed of the /spl alpha/-EM algorithm was reported for learning problems, this paper shows that closed-form E-steps can be obtained for a wide class of problems. There is a set of common techniques. That is, a cookbooks for the /spl alpha/-EM algorithm is presented. The recipes include unsupervised neural networks, supervised neural networks for various gating, hidden Markov models and Markov random fields for moving object segmentation. Reasoning for the speedup is also given.
Yasuo Matsuyama, Takayuki Ikeda, Tomoaki Tanaka, Satoshi Furukawa, Naoki Takeda, Takeshi Niimoto
IJCNN1
1998 A Hierarchy from alfa-EM Algorithm to Vector Quantization and Self Organization
Yasuo Matsuyama, Naoki Takeda, Satoshi Furukawa, Takeshi Niimoto
ICONIP1
1998 Multiple descent cost competition: restorable self-organization and multimedia information processing
abstract
Multiple descent cost competition is a composition of learning phases for minimizing a given measure of total performance, i.e., cost. If these phases are heterogeneous toward each other, the total learning algorithm shows a variety of extraordinary abilities; especially in regards to multimedia information processing. In the first phase of descent cost learning, elements of source data are grouped. Simultaneously, a weight vector for minimal learning, (i.e., a winner), is found. Then, the winner and its partners are updated for further cost reduction. Therefore, two classes of self-organizing feature maps are generated. One is called a grouping feature map, which partitions the source data. The other is an ordinary weight vector feature map. The grouping feature map, together with the winners, retains most of the source data information. This feature map is able to assist in a high quality approximation of the original data. Traditional weight vector feature maps lack this ability. Another important capacity of the grouping feature map is that it can change its shape. Thus, the grouping pattern can accept external directions in order to metamorphose. In the text, the total algorithm of the multiple descent cost competition is explained first. In that section, image processing concepts are introduced in order to assist in the description of this algorithm. Then, a still image is first data-compressed (DC). Next, a restored image is morphed using the grouping feature map by receiving directions given by an external intelligence. Next, an interpolation of frames is applied in order to complete animation coding (AC). Thus, multiple descent cost competition bridges "DC to AC." Examples of multimedia processing on virtual digital movies are given.
Yasuo Matsuyama
IEEE Trans. Neural Networks1
1996 Harmonic competition: a self-organizing multiple criteria optimization
abstract
Harmonic competition is a learning strategy based upon winner-take-all or winner-take-quota with respect to a composite of heterogeneous subcosts. This learning is unsupervised and organizes itself. The subcosts may conflict with each other. Thus, the total learning system realizes a self-organizing multiple criteria optimization. The subcosts are combined additively and multiplicatively using adjusting parameters. For such a total cost, a general successive learning algorithm is derived first. Then, specific problems in the Euclidian space are addressed. Vector quantization with various constraints and traveling salesperson problems are selected as test problems. The former is a typical class of problems where the number of neurons is less than that of the data. The latter is an opposite case. Duality exists in these two classes. In both cases, the combination parameters of the subcosts show wide dynamic ranges in the course of learning. It is possible, however, to decide the parameter control from the structure of the total cost. This method finds a preferred solution from the Pareto optimal set of the multiple object optimization. Controlled mutations motivated by genetic algorithms are proved to be effective in finding near-optimal solutions.
Yasuo Matsuyama
IEEE Trans. Neural Networks1
1990 Multiple descent cost competitive learning: batch and successive self-organization with excitatory and inhibitory connections
abstract
Novel general algorithms for multiple-descent cost-competitive learning are presented. These algorithms self-organize neural networks and possess the following features: optimal grouping of applied vector inputs, product form of neurons, neural topologies, excitatory and inhibitory connections, fair competitive bias, oblivion, winner-take-quota rule, stochastic update, and applicability to a wide class of costs. Both batch and successive training algorithms are given. Each type has its own merits. However, these two classes are equivalent, since a problem solved in the batch mode can be computed successively, and vice versa. The algorithms cover a class of combinatorial optimizations besides traditional standard pattern set design
Yasuo Matsuyama
IJCNN1
1990 Competitive self-organization and combinatorial optimization: applications to traveling salesman problem
abstract
The author discusses algorithms of competitive self-organization and their application to a typical combinatorial problem, the traveling salesman problem. The main feature of the proposed algorithm is the sophisticated use of excitatory/inhibitory intralayer connections of neurons combined with a judicious selection of neural network topology. Such properties contribute to obtaining excellent approximate solutions. Five hundred sets of 30-city solutions are compared with those obtained by a pure simulated annealing method. From this comparison, it is found that a considerable number of the solutions obtained by this self-organization method are highly likely to be the optimal tours. Successive training algorithms are mainly used; however, applications of batch training algorithms are also discussed. Implications for multisalesman problems are discussed
Yasuo Matsuyama
IJCNN1
1987 Variable region vector quantization, space warping and speech/Image compression
abstract
Algorithms for vector quantization of variable region data are given. The design iteration is proved to converge. An important issue here is the optimization step of the region shape with respect to the vector quantization codebook. Thus, the presented design method is a nontrivial extention of ordinary vector quantizer design which contains the classical Lloyd-Max algorithm. First, the main algorithm is given without introducing any physical entity. Therefore, the method is applicable to any data including speech and image as long as the quantization distortion is defined. In the speech coding case, which is the main body of this paper, the region shape optimization is interpreted as the epoch interval adjustment. The selection of the adjusted epochs with respect to the vector quantization codebook considerably reduces the quantizing distortion. This enables very-low-rate speech compression. Then, the image coding case is formulated and some convergence problem is discussed.
Yasuo Matsuyama
ICASSP1
1986 Joint time-spectral vector quantization and inverse filter set
abstract
Joint time-spectral vector quantization to achieve much lower bit rates on the average than ordinary spectral vector quantizers is discussed. The principle and used quantities are closed within the theory of LPC so that theoretical clearness and the circumvention of unnecessary system complexity are promoted. The presented theory and method lead to an architecture for a pipelined inverse filter array for VLSI.
Yasuo Matsuyama
ICASSP1
1982 Voice Coding and Tree Encoding Speech Compression Systems Based Upon Inverse Filter Matching
abstract
Two speech compression systems based on codebooks of inverse filters produced by off-line linear predictive coding (LPC) and vector quantization (VQ) techniques are considered. The first system is a pitch excited vocoder that is a variation on a speech coding system based upon vector quantization. The encoder selects an LPC reverse filter from a finite codebook that best "matches" an observed frame of sampled speech. This filter is in turn used to determine the voicing and digitized pitch information. Unlike LPC systems, the digitization is performed in a single step on the data rather than separate modeling and digitization steps. The second system is a tree encoding system that uses the filter selected by an inverse filter matching vocoder to "color" a tree that is then searched for a minimum distortion path for the original sampled speech waveform. This system can be viewed as a hybrid between an adaptive predictive coder and a universal tree encoder. The two systems are described, simulated, and compared with other similar systems.
Yasuo Matsuyama, Robert M. Gray
IEEE Trans. Commun.1
1981 Universal tree encoding for speech
abstract
A low-rate (about one bit per sample) waveform coder for speech compression is designed using techniques from universal source coding, fake process tree encoding, and linear predictive coding (LPC). The system does not require on-line adaptation or LPC analysis, yet it yields a fidelity that compares well with the best existing adaptive-waveform coder of the same rate.
Yasuo Matsuyama, Robert M. Gray
IEEE Trans. Inf. Theory1
1980 Mismatch Robustness of Linear Prediction and Its Relationship to Coding
Yasuo Matsuyama
Inf. Control.1