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IEEE Region 8 International Symposium on Video/image processing and Multimedia communications (EURASIP)

作者： S. Plevel T. Javornik G. Kandus R. Trobec Jožef Stefan Institute Ljubljana Slovenia

The adaptive data mapping of wavelet compressed images in multiple input multiple output (MIMO) wireless communication systems is proposed and analyzed. image compression methods based on wavelet transform allow image decomposition in blocks, representing signal frequency bands at different resolutions. Blocks representing low frequencies are very important for visual image quality, while the highest frequency blocks, even lost, have almost no impact on image quality. MIMO systems offer parallel subchannels with different quality. Mapping more important data to higher quality subchannels improves the image quality. The results obtained by analog devices wavelet algorithm, implemented in a single chip ADV601, used in the MIMO system with four transmit and four receive antennas, show that the adaptive data mapping approach improves the peak signal to noise ratio (PSNR) up to 8 dB in comparison to standard data mapping.

关键词： image coding MIMO Frequency image quality Signal mapping PSNR Adaptive systems Wavelet analysis Wireless communication image analysis

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Wavelet-based compression of segmented images

Wavelet-based compression of segmented images

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IEEE Region 8 International Symposium on Video/image processing and Multimedia communications (EURASIP)

作者： R. Vargic Faculty of Electrical Engineering And Information technology Slovak University of Technology Bratislava Slovakia

In this article we present an approach to compression of segmented images using wavelet transform. The original image is segmented using an unsupervised regions segmentation method. The segments are approximated using polygons to minimise the representation. For texture approximation we use iterated wavelet orthogonal transform. We develop a new scheme for approximation and coding which optimises the results in rate-distortions sense. Proposed scheme gives comparative results to T. Karlubikova et al. (2002) but with significant speed-up of computation.

关键词： image coding image segmentation Wavelet transforms Discrete wavelet transforms Partitioning algorithms Approximation algorithms Information technology Object oriented methods Discrete cosine transforms Discrete transforms

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A novel interpolation method for preserving image details by using the fuzzy technique

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ELECTRONICS AND communications IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE 2003年第3期86卷 57-66页

作者： Kimura, T Taguchi, A Murata, Y IBM Japan Ltd Kanagawa 2428502 Japan Musashi Inst Technol Fac Engn Tokyo 1588557 Japan

Enlargement processing of digital images is usually carried out by means of an interpolation function obtained by simplification of the sinc function. However, in such an interpolation method, restoration of the high-frequency components lost in digitizing the images is not carried out at all. Hence, the enlargement causes blurring for images with many edges and detailed signals. For one-dimensional signals, Carrato and colleagues have proposed an interpolation method in which the discontinuities of the step edge signals are preserved while other signals are linearly interpolated. In this method, no blurring occurs in the expansion processing of strong frames of the images. However, Carrato's method has the following problems. (1) Only the step edges in the image signals are taken into account so that consideration of the detailed signals is insufficient. (2) Extension of the one-dimensional interpolation method given by Carrato to a two-dimensional interpolation method has a problem in interpolation at the center of the lattice. In this paper, a method is proposed to accomplish improvement of Carrato's method. With regard to problem (1), the interpolation not only is effective for the step edge signals but also preserves the apex of the peak and valley signals. With regard to problem (2), improvement is planned by directly deriving the interpolation value from the original signals. The proposed interpolation processing is accomplished by describing the processing sequence by a rule. The proposed method consists of two sets of fuzzy reasoning. The proposed method and the conventional interpolation method are compared from the numerical and visual perspectives and the effectiveness of the proposed method is clarified. (C) 2002 Wiley Periodicals, Inc.

关键词： fuzzy reasoning interpolation image enlargement

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PDE-based region tracking without motion computation by joint space-time segmentation

PDE-based region tracking without motion computation by join...

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IEEE International conference on image processing

作者： A.-R. Mansouri A. Mitiche M. Aron Division of Engineering and Applied Mathematics Harvard University Cambridge MA USA Institut National de la Recherche Scientifique Place Bonaventure INRS-Télécommunications Montreal QUE Canada

In this paper, we propose a novel algorithm for region tracking without motion computation that uses as its starting point the Bayesian framework for tracking previously developed [A.-R. Mansouri, July 2002], [A.R. Mansouri, A. Mitiche, 2002], extending it to a multi-frame tracking algorithm in which tracking is expressed as segmentation in the spatio-temporal domain [***, et al., April 2002]. Our proposed algorithm is expressed as the solution of level set partial differential equations and the tracked region in a particular frame of the sequence is then obtained as the time slice of the level surface given by the level set equations. The main benefit of our proposed algorithm is that contrary to numerous other tracking algorithms, it is a multi-frame tracking algorithm which does not assume the motion to be small [M. Bertalmio, et al., 1998], nor the background to be stationary [S. Jehan-Besson, et al., 2000], nor the region to be uniform in intensity on a uniform background [N. Paragios, R. Deriche, 2000], nor does it assume any motion models [A. Mitiche, et al., April 2002]. This leads to a tracking algorithm which combines the advantages of the Bayesian formulation developed for frame-to-frame tracking [A.-R. Mansouri, July 2002] with those of the formulation in the spatio-temporal domain [A. Mitiche, et al., April 2002]. We illustrate the performance of our algorithm on real image sequences with natural motion.

关键词： Tracking Bayesian methods image segmentation Level set image sequences Partial differential equations Mathematics image processing Computer vision Application software

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Improving shape-based face recognition by means of a supervised discriminant Hausdorff distance

Improving shape-based face recognition by means of a supervi...

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IEEE International conference on image processing

作者： J.L. Alba A. Pujol A. Lopez J.J. Villanueva Signal Theory and Communications Department University of Vigo Spain Digital Pointer MVT Centre de Visio per Computador Universitat Authnòma de Barcelona Spain

This paper introduces a supervised discriminant Hausdorff distance that fits into the framework for automatic face analysis and recognition proposed in [A. Pujol et al.,2002]. Our proposal relies solely on face shape variation contrarily to most of the successful model-based approaches, and results show comparable performance to them. The whole framework is based in a new set of Hausdorff measures and defines face-shape based similarity measures and supervised criteria to add discriminant capabilities to the Hausdorff distance. The paper presents experimental results supporting the proposed methodologies.

关键词： Face recognition Shape measurement Distortion measurement Lighting Face detection image analysis Random variables image coding image representation Encoding

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Sampling and interpolation of the plenoptic function

Sampling and interpolation of the plenoptic function

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IEEE International conference on image processing

作者： A. Chebira P.L. Dragotti L. Sbaiz M. Vetterli Audio-visual Communications Laboratory Swiss Federal Institute of Technology Lausanne Switzerland Electrical and Electronic Engineering Imperial College London UK EECS Department University of California Berkeley Berkeley CA USA

In this paper, we present reconstruction schemes for the plenoptic function. Using new sampling methods, we show that, for some particular scenes, it is possible to perfectly reconstruct the plenoptic function from a finite number of cameras with finite resolution (Theorem 1 and Corollary 1). In more general cases, we demonstrate new ways of interpolating exactly the plenoptic function (Theorem 2). Finally, we show that it is possible to infer camera locations from a finite set of images. In all cases, we have perfect solutions due to the super-resolution property of the sampling. First numerical experiments on noisy observations show the potentiality of this new theoretical developments.

关键词： Sampling methods Interpolation Cameras Layout Signal resolution Propulsion image sampling Temperature sensors Rendering (computer graphics) Laboratories

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Disparity dependent segmentation based stereo image coding

Disparity dependent segmentation based stereo image coding

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IEEE International conference on image processing

作者： R. Shukla H. Radha M. Vetterli Audio-visual Communications Laboratory Swiss Federal Institute of Technology Switzerland Department of ECE Michigan State University East Lansing USA

In this paper, we propose a novel rate-distortion (R-D) optimized disparity based coding scheme for stereo images. This new scheme efficiently integrates the coding of the disparity field with the residual image obtained via disparity estimation/compensation (DE/DC) in an R-D framework. The scheme first performs a quadtree decomposition of the target image and computes the disparity information along with the residual image for each node in the tree. An R-D based algorithm is then used for optimum bit allocation among the different quadtree nodes. The proposed scheme further jointly encodes the neighboring nodes with similar disparity information to attain higher coding gains. We present simulation results for the proposed scheme and compare these results with the performance of a fixed block size DE/DC based JPEG2000 stereo image coder. Our simulations show that the proposed scheme outperforms the fixed block size based disparity compensated JPEG2000 coder by more than 0.5 dB.

关键词： image segmentation image coding Stereo vision image storage Pixel Motion estimation Laboratories Rate-distortion Bit rate Computational modeling

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An efficient video classification system based on HMM in compressed domain

An efficient video classification system based on HMM in com...

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International conference on Information, communications and Signal processing

作者： Yi Haoran D. Rajan Chia Liang-Tien Center for Multimedia and Network Technology School of Computer Engineering Nanyang Technological University Singapore

ISBN: (纸本)0780381858

In this paper, we present our method for effective and efficient classification of different types of video that make use of the low level visual features, color and motion features. The color features, similar to the MPEG-7 scalable color descriptors, are the compressed color histograms extracted from the DC images of the video sequences. The motion features, similar to MPEG-7 motion activity descriptors, are extracted from the motion vectors. Both features are extracted from the compressed domain and give a good characterization of the video in both the spatial and temporal dimension. We then classify different types of video using hidden Markov model. First, we train the hidden Markov model for each type of video. Then the trained HMMs are used to classify incoming videos using maximum likelihood classification.

关键词： Video compression Hidden Markov models image coding MPEG 7 Standard Histograms Feature extraction Pattern classification Intelligent networks Computer networks Video sequences

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An overview of a real-time contents edition system for MPEG-4

An overview of a real-time contents edition system for MPEG-...

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IEEE Pacific Rim conference on communications, Computers and Signal processing

作者： Y. Miura M. Katsumoto Communications Research Laboratories Koganei Tokyo Japan

We propose a real-time contents edition system that allows the input of multiple audio-visual streams and simultaneous encoding into MPEG-4 video objects, editing, and delivery. This system is designed to enable the provision of content based on live video from multiple locations. Our system consists of editing, streaming, and display modules. Streaming and display modules can join/depart from the system while it is operating. To distribute high quality live video movies in different environments, content can also be encoded adaptively in various environments. In this paper, we present an overview of our real-time contents edition system. We also describe the algorithm used to decide whether inter-frame compression should be done frame-by-frame. The suitability of our algorithm was shown in an experimental implementation of the DV-MPEG transducer.

关键词： Real time systems MPEG 4 Standard Encoding Motion pictures Hardware image coding Video compression Streaming media Broadband communication Bandwidth

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Integrated end-to-end buffer management and congestion control for scalable video communications

Integrated end-to-end buffer management and congestion contr...

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IEEE International conference on image processing

作者： I.V. Bajic O. Tickoo A. Balan S. Kalyanaraman J.W. Woods ECSE Department Rensselaer Polytechnic Institute Troy NY USA

In this paper we present a video communication system that integrates end-to-end buffer management and congestion control at the source with the playout adjustment mechanism at the receiver. While each component of the system has been considered independently in the literature, our focus in this work is their integration. The proposed system exploits the fact that when congestion control is implemented at the source, most of the loss occurs at the source and not within the network. Based on this observation, we design the buffer management to trade off random loss for controlled loss of visually less important data. Frame rate is adjusted at the receiver to maximize the visual quality of the displayed video based on the overall loss. We tested our system with both H.26L and a subband/wavelet video coder, and found that it significantly improves the received video quality in both cases.

关键词： Communication system control Scalability Propagation losses Delay Quality management Control systems System testing Internet Bandwidth Protocols

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