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conference on visual Data Exploration and Analysis II

作者： DATTA, S GUHA, R UNIV CENT FLORIDA DEPT COMP SCIORLANDOFL 32816

In this parallel surface rendering algorithm based on dividing cube2 on a SIMD machine MasPar MP-1, we address the problem of load balancing and image composition. We divide a 3D array of Nx x Ny x Nz volume data into... 详细信息

ISBN: (纸本)0819417572

In this parallel surface rendering algorithm based on dividing cube² on a SIMD machine MasPar MP-1, we address the problem of load balancing and image composition. We divide a 3D array of N_x x N_y x N_z volume data into N_x x N_y columns, each N_z deep. Each processor in the mesh receives a subvolume of such data columns. All processors synchronously traverse its subvolume to determine the voxels intersecting the isosurface. Intersecting voxels are called isovoxels. Partial load balancing distributes the isovoxels contained in a row of processors evenly among the processors in that row to reduce the network traffic and complexity of the rendering phase. Each isovoxel is subdivided into point primitives using dividing cube algorithm. Rendering algorithm transforms the surface points and their normals and projects them into the view plane.

关键词： Data processing Algorithm development Data communications Raster graphics Transform theory 3D displays Medical imaging Volume rendering Computer graphics Computer science

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A STUDY ON MOUTH SHAPE-FEATURES SUITABLE FOR HMM SPEECH RECOGNITION USING FUSION OF visual AND AUDITORY INFORMATION

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS communications AND COMPUTER SCIENCES 1995年第11期E78A卷 1548-1552页

作者： DOI, N SHINTANI, A HAYASHI, Y OGIHARA, A TAKAMATSU, S Univ of Osaka Prefecture Sakai-shi Japan

Recently, some speech recognition methods using fusion of visual and auditory information have been researched. In this paper, a study on the mouth shape image suitable for fusion of visual and auditory information has been described. Features of mouth shape which are extracted from gray level image and binary image are adopted, and speech recognition using linear combination method has been performed. From results of speech recognition, the studies on the mouth shape features which are effective in fusion of visual and auditory information have been performed. And the effectiveness of using two kinds of mouth shape features also has been confirmed.

关键词： SPEECH RECOGNITION FUSION OF visual AND AUDITORY INFORMATION FEATURE OF MOUTH SHAPE image processing

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Speech-assisted lip synchronization in audio-visual communications

Speech-assisted lip synchronization in audio-visual communic...

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IEEE International conference on image processing

作者： Tsuhan Chen H.P. Graf B. Haskell E. Petajan Yao Wang H. Chen Wu Chou Nokia Bell Labs Holmdel Holmdel NJ US AT&T Bell Labs. Holmdel NJ USA AT and T Bell Laboratories Inc. Murray Hill NJ USA AT and T Bell Laboratories Inc. Holmdel NJ USA

We utilize speech information to improve the quality of audio-visual communications such as video telephony and videoconferencing. We show that the marriage of speech analysis and image processing can solve problems related to lip synchronization. We present a technique called speech-assisted frame-rate conversion, and apply it to coding of talking head video. Demonstration sequences are presented. Extensions and other applications are outlined.

关键词： image converters Mouth image coding Head Speech analysis image processing Decoding Humans image motion analysis image sequence analysis

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A fixed-length compression method using the Karhunen-Loeve transform

A fixed-length compression method using the Karhunen-Loeve t...

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IEEE Pacific Rim conference on communications, Computers and Signal processing

作者： P. Nasiopoulos M. Yedlin R.K. Ward Department of Electrical Engineering University of British Columbia Vancouver BC Canada

A compression method is presented which combines the distinct advantage of being fixed length with the visual picture quality of transform-based coding methods. This method compresses the Karhunen-Loeve transform coefficients of 8/spl times/8 pixel blocks of the picture and attains a compression ratio of 15.37:1 for color images. Compared to the absolute moment block truncation coding, the other known fixed length compression method, our method improves the compression ratio by 68% and significantly improves the visual quality of the reconstructed picture.

关键词： Karhunen-Loeve transforms image coding Covariance matrix image reconstruction Pixel Color Discrete cosine transforms Symmetric matrices communications technology Transform coding

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image quality criterion based on the cancellation of the masked noise

Image quality criterion based on the cancellation of the mas...

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International conference on Acoustics, Speech, and Signal processing (ICASSP)

作者： S. Comes O. Bruyndonckx B. Macq Laboratoire de Teéleécommunications et Teéleédeétection Universite Catholique de Louvain Louvain-la-Neuve Belgium

This paper investigates the development of a new image quality criterion based on the psychovisual model of tuned channels and more particularly the phenomenon of masking. The masking model parameters have been evaluated by psychovisual tests assuming a logarithmic relationship between the visibility threshold and the contrast value of the background for a given perceptual channel. The masking has the consequence that only a part of the noise of a noisy image is really visible and affects the visual quality of the image. The idea of the proposed criterion is to evaluate the image quality after the cancellation of the masked noise defined as the invisible noise. The criterion has been used in order to compare different coders and different post-processings of noisy images.

关键词： image quality Noise cancellation Psychology Testing

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Optical flow techniques applied to video coding

Optical flow techniques applied to video coding

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IEEE International conference on image processing

作者： R. Krishnamurthy P. Moulin J. Woods Center for Image Processing Research & ECSE Department Rensselaer Polytechnic Institute Troy NY USA Bell Communications Research Inc. Morristown NJ USA

Motion estimation is an important part of most video coding schemes because it enables us to exploit the high degree of temporal redundancy present. Though block matching algorithms (BMA) yield coarse and piecewise-constant fields, they are very popular due to their simplicity and low bit overhead. In this paper, we propose to use a more advanced gradient-based technique to overcome the disadvantages of BMA. A dense motion field is estimated and compressed using a hierarchical finite element (HFE) representation, leading to an efficient, highly parallel, iterative, multiresolution optimization algorithm. The scheme also uses multiresolution measurements and a coarse-to-fine strategy to estimate large displacements. At comparable bit rates, the motion fields are much smoother and more natural than those produced by BMA. Coding gains of about 0.6 dB were obtained on Claire. More importantly, substantial visual improvements were obtained, mainly due to improved performance near the edges.

关键词： image motion analysis Video coding Motion estimation Equations image coding image processing Finite element methods Lead Spatial resolution Iterative algorithms

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Perceptual embedded image coding using wavelet transforms

Perceptual embedded image coding using wavelet transforms

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IEEE International conference on image processing

作者： A. Mazzarri R. Leonardi Signals and Communications Laboratory D.E.A D.E.A. University of Brescia Italy

We present a modified version of an embedded wavelet coding scheme, first suggested by Shapiro (see IEEE Transactions on Signal processing, vol.41, no. 12, p.3445-3462, 1993), that improves the performance of the original algorithm in a visual subjective distortion sense. We preserve the features of the original Shapiro's embedded coder. It is possible to choose a fixed target bit rate, as the information needed to represent an image coded at some rate always contains the needed information for the same image coded at lower rates. Therefore, the decoder can cease decoding the bit stream at any point, simulating an image coded at a lower rate corresponding to the truncated bit stream. We also introduce some perceptive improvements by adopting different (more regular) filters with respect to the original QMF pyramid filters proposed by Simoncelli, Hingorani et al. (1987) and used by Shapiro. These filters are synthesized using a "wavelet approach" instead of a "subband approach", and this leads to a better control on their regularity properties, jointly with better perceptual performance.

关键词： image coding Wavelet transforms Filters Discrete wavelet transforms Streaming media Quantization Wavelet packets Bit rate Decoding Entropy coding

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Rate conversion of MPEG coded video by re-quantization process

Rate conversion of MPEG coded video by re-quantization proce...

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IEEE International conference on image processing

作者： Y. Nakajima H. Hori T. Kanoh Visual Communications Group KDD Research and Development Laboratories Inc. Ohara Saitama Japan

We propose rate conversion method by re-quantization in which MPEG coded video at high bit rate is converted into the MPEG bitstream at a lower bit rate without decoding to obtain the reconstructed picture. The quantization step required for re-quantization is determined by the local and global quantization steps which are closely related to the activities in the pixel domain. The simulation results show that very similar rate distortion curves to those of transcoding have been obtained, and the difference in SNR is relatively small, about 0.4 dB at 1 Mbit/s in MPEG1 using a master bitstream at 4 Mbit/s, and 1 dB at 3 Mbit/s in MPEG2 using a master at 9 Mbit/s. Since the proposed method is very simple and requires much less hardware implementation cost than transcoding, it has a significant advantage as a rate conversion tool.

关键词： Bit rate Decoding Video compression image converters Quantization Transcoding Costs Scalability Discrete cosine transforms Multimedia communication

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An Analog visual Feature Extraction Retina for Real-Time Stereo Vision

An Analog Visual Feature Extraction Retina for Real-Time Ste...

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European conference on Solid-State Circuits (ESSCIRC)

作者： Bogdan Arion Yang Ni Francis Devos Université Paris Sud Orsay France Institut National de Télécommunications Evry France

In this paper, we present an analog VLSI spatio-frequency analysis based visual feature extraction retina, dedicated to the real-time stereo vision. In this retina, local extreme points in the DoG filtered image are extracted as pertinent visual features. A 128-pixel line-based prototype chip is presented with experiment results. A processing speed of 100k lines/s has been obtained (exposition time excluded), it will be used in an integrated analog stereo vision system for real-time obstacle detection task.

关键词： Feature extraction Retina Stereo vision Band pass filters Switched capacitor networks MOS capacitors Very large scale integration Data mining Circuits Filtering theory

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VLSI implementation of discrete wavelet transform

VLSI implementation of discrete wavelet transform

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Annual IEEE International conference and Exhibit ASIC

作者： A. Grzeszczak T.H. Yeap S. Panchanathan Visual Computing and Communications Laboratory Department of Electrical Engineering University of Ottawa Ottawa ONT Canada

This paper presents a VLSI implementation of discrete wavelet transform (DWT). The architecture is systolic in nature and performs both high-pass and low-pass coefficient calculations with only one set of multipliers, in contrast to the approaches presented in the literature. The architecture is simple, modular, and cascadable, and has been implemented in VLSI. Experimental results show that real-time coefficient calculation on a 512/spl times/512 monochrome video input can be achieved with 1.2 /spl mu/m technology.

关键词： Discrete wavelet transforms Very large scale integration Discrete cosine transforms Wavelet transforms Computer architecture image coding Finite impulse response filter Video compression image reconstruction image processing

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