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Data Compression Conference (DCC)

作者： Shih-Ta Hsiang Center for Image Processing Research and Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy NY USA

ISBN: (纸本)0769510310

In this paper, we present a new embedded wavelet image coding system using quadtree splitting and context modeling. It features low computational complexity and high compression efficiency, thanks to joint utilization of two powerful embedded coding techniques-set partitioning and context modeling. With effective exploitation of strong statistical dependencies among the quadtree nodes built up from subband coefficients, the proposed algorithm substantially improves the coding efficiency of the existing set-partition coders for both lossy and lossless image compression. For example, our experimental results show that the new algorithm respectively outperforms zerotree-based SPIHT and quadtree-based SPECK by 0.7 dB and 1.0 dB at 0.5 bpp on an average.

关键词： image coding Wavelet coefficients Context modeling Partitioning algorithms Transform coding image processing Embedded computing Power engineering computing Power engineering and energy systems engineering and theory

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Multi-layered video transmission over wireless channels using an adaptive modulation and coding scheme

Multi-layered video transmission over wireless channels usin...

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IEEE International Conference on image processing

作者： Y. Pei J.W. Modestino Center for Image Processing Research Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy NY USA

In this paper we describe a multi-layered video transport scheme for wireless channels capable of adapting to channel conditions in order to maximize end-to-end quality of service (QoS). This scheme combines a scalable H.263+ video source coder with unequal error protection (UEP) across layers. The UEP is achieved by employing different channel codes together with a multiresolution modulation approach to transport the different priority layers. Adaptivity to channel conditions is provided through use of joint source-channel coding (JSCC) which attempts to jointly optimize the source and channel coding rates together with the modulation parameters to obtain the maximum achievable end-to-end QoS for the prevailing channel conditions. Results indicate that this adaptive JSCC scheme employing scalable video encoding together with a multiresolution modulation/coding approach leads to significant improvements in delivered video quality for specified channel conditions. In particular, the approach results in considerably improved graceful degradation properties for decreasing channel SNR.

关键词： Modulation coding image coding Signal resolution Video coding Quality of service Constellation diagram systems engineering and theory Error correction codes Channel coding Degradation

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Real-time out-of-core visualization of particle traces

Real-time out-of-core visualization of particle traces

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IEEE Symposium on Parallel and Large-Data Visualization and Graphics (PVG)

作者： R. Bruckschen F. Kuester B. Hamann K.I. Joy Visualization and Graphics Research Group Center for Image Processing and Integrated Computing Department of Computer Science University of California Davis CA USA Visualization and Interactive Systems Group Department of Electrical and Computer Engineering University of California Irvine CA USA

ISBN: (纸本)0780372239

Visualization of particle traces provides intuitive and efficient means for the exploration and analysis of complex vector fields. The paper presents a method suitable for the real-time visualization of arbitrarily large time-varying vector fields in virtual environments. We describe an out-of-core scheme in which two distinct pre-processing and rendering components enable real-time data streaming and visualization. The presented approach yields low-latency application start-up times and small memory footprints. The described system was used to implement a "volumetric fog lance," which can emit up to 60000 particles into a flow field while maintaining an interactive frame rate of 60 frames per second. All algorithms were specifically designed to support commodity hardware. The proof-of-concept system is running on a low-cost Linux workstation equipped with a 120 GB E-IDE RAID (redundant array of inexpensive disk) system.

关键词： Data visualization Computational modeling Computational fluid dynamics Motion pictures Hardware computer graphics Interactive systems image processing computer science image analysis

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Multi-layer image compression algorithm for e-commerce

Multi-layer image compression algorithm for e-commerce

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IEEE International Conference on systems, Man and Cybernetics

作者： R. Kounchev R. Kouncheva S.H. Rubin M. Milanova Laboratory of Image Processing Technical University of Sofia Sofia Bulgaria Space and Naval Warfare Systems Center San Diego San Diego CA USA Computer Engineering and Computer Science Department University of Louisville Louisville KY USA

A new method for pyramidal image decomposition called inverse is presented. This method permits to obtain first low resolution components while mainly concentrating image energy in these first components. Each one of its components is defined on the basis of approximating models representing the so called oriented surfaces of second degree, which constitute the different levels of the corresponding difference pyramid in the image space with minimum mean-square error (MSE). The inverse pyramidal decomposition (IPD) is compared to the pyramidal structures based on the well-known Laplacian pyramid and to the related reduced pyramids.

关键词： image coding Business image restoration Visualization image quality Laboratories image processing Military computing computer science USA Councils

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Embedded image coding using zeroblocks of subband/wavelet coefficients and context modeling

Embedded image coding using zeroblocks of subband/wavelet co...

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IEEE International Symposium on Circuits and systems (ISCAS)

作者： Shih-Ta Hsiang J.W. Woods Center for Image Processing Research and Electrical Computerand Systems Engineering Department Rensselaer Polytechnic Institute Troy NY USA

With fast computation and excellent compression efficiency, two embedded coding techniques, zero-tree/-block coding and context modeling of the subband/wavelet coefficients, have been widely utilized for image coding applications. In this research, we present a new embedded wavelet image coding algorithm with an attempt to combine advantages of these two successful coding schemes. The experimental results show that the proposed algorithm outperforms the respected zero-tree/-block coders, SPIHT and SPECK, in compression efficiency. It is also comparable to the state-of-art JPEG 2000 test coder in PSNR performance while retaining the attractive low-complexity feature of the zeroblock coders.

关键词： image coding Context modeling Discrete wavelet transforms Testing PSNR Arithmetic Partitioning algorithms image processing systems engineering and theory Embedded computing

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A joint source-channel coding approach to scalable delivery of digital video over ATM networks

A joint source-channel coding approach to scalable delivery ...

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IEEE International Conference on image processing

作者： R. Kurceren J.W. Modestino Electrical Computer and Systems Engineering Department Center for Image Processing Research Rensselaer Polytechnic Institute Troy NY USA

ISBN: (纸本)0780362977

A joint source-channel coding (JSCC) approach for ATM-based network transport of scalable variable bit rate (VBR) digital video is described. We provide a new methodology for finding the optimum source and channel coding rates, together with the optimum data-partitioning ratio, to maximize the statistical multiplexing gain while maximizing the end-to-end video quality. The results provide a quantitative demonstration of the effectiveness of a scalable delivery approach over the single-layer JSCC.

关键词： Streaming media Forward error correction image coding Channel coding Error correction codes Asynchronous transfer mode Error correction Protection computer networks systems engineering and theory

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A joint source-channel coding approach to network transport on digital video

A joint source-channel coding approach to network transport ...

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IEEE Annual Joint Conference: INFOCOM, IEEE computer and Communications Societies

作者： B. Kurceren J.W. Modestino Dept. of Electr. Comput. & Syst. Eng. Rensselaer Polytech. Inst. Troy NY USA Electrical Computer and Systems Engineering Department Center for Image Processing Research Rensselaer Polytechnic Institute Troy NY USA

The use of forward error-control (FEC) coding, possibly in conjunction with passive-error recovery techniques, has emerged as a promising approach for real-time video transport over ATM networks for cell loss recovery and/or bit error correction, such as might be required for wireless links. Although FEC provides cell-loss recovery, through its erasure correcting capabilities, it also introduces transmission overhead which can possibly cause additional cell losses. A joint source-channel coding methodology is described to maximize the number of video sources multiplexed at a given quality of service (QoS), measured in terms of overall reproduced video quality. The transport channel is modeled as a block interference channel (BIC) and the multiplexer as a single server, deterministic service, finite buffer supporting N users. Based upon an information-theoretic characterization of the BIC and large deviation bounds on the buffer overflow probability, we describe a methodology that provides theoretically achievable upper limits on the number of sources multiplexed at a given level of performance. Performance of a specific coding technique using an MPEG-2 source encoder and interlaced non-binary Reed-Solomon (RS) channel codes is illustrated and shown to approach the information-theoretic predictions with increasing levels of complexity.

关键词： Forward error correction Quality of service Error correction Asynchronous transfer mode Error correction codes Propagation losses Interference channels Multiplexing Buffer overflow Reed-Solomon codes

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image IDENTIFICATION AND RESTORATION IN THE SUBBAND DOMAIN (VOL 3, PG 312, 1994)

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IEEE TRANSACTIONS ON image processing 1994年第6期3卷 873-873页

作者： KIM, JM Center for Image Processing Research and Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy NY USA

When faced with a large support point spread function (PSF), the iterative expectation-maximization (EM) algorithm, which is often used for PSF identification, is very sensitive to the initial PSF estimate. To deal with this problem, the authors propose to do EM image identification and restoration in the subband domain. After the image is first divided into subbands, the EM algorithm is applied to each subband separately. Since the PSF can be taken to have smaller support in each subband, these subbands should be less of a problem with the EM model identification. They also introduce an adaptive subband EM method for use in the upper frequency subbands.

关键词： restoration bearing point subband Subbands expectation-maximisation algorithm Point spread function image recognition

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Region-based coding of images using a spline model

Region-based coding of images using a spline model

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IEEE International Conference on image processing

作者： R. Baseri J.W. Modestino Electrical Computer and Systems Engineering Department Center for Image Processing Research Rensselaer Polytechnic Institute Troy NY USA

This paper describes a second-generation region-based coding scheme operating in a subband environment. Specifically, this is a compression technique based on approximating the lowest-frequency subband of an image with a 2-D spline model. Following a segmentation procedure, parametric polynomials are fitted to the resulting regions of the lowest-frequency subband. This subband is then represented by the spline coefficients, the region boundary description and the residual error. The residual error plus the higher-frequency subbands are encoded using conventional pixel-based quantization schemes while we describe an efficient encoding scheme for the 2-D spline representation. An entropy-constrained design procedure is developed for designing these individual encoders to minimize the overall mean-square distortion subject to a constraint on the output entropy. A comprehensive study of the operational rate-distortion performance of the resulting scheme is presented, which indicates the superiority of this approach to the more traditional pixel-based entropy-constrained schemes.< >

关键词： image coding Spline Polynomials Pixel image segmentation systems engineering and theory image processing Quantization Entropy Contracts

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Entropy-Constrained Subband Coding of images Using a Perceptual Distortion Criteria

Entropy-Constrained Subband Coding of Images Using a Percept...

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IEEE International Symposium on Information Theory

作者： C.F. Harris J.W. Modestino Electrical Computer and Systems Engineering Department Center for Image Processing Research Rensselaer Polytechnic Institute Troy NY USA

A new perceptually relevant entropy-constrained coding scheme based on the just-noticable-distortion (JND) level of the human observer is described and its properties demonstrated. The JND at each pixel location is defined as the threshold of detectability of the human visual system (HVS) to errors in reproducing that pixel. Because of the masking effect of the HVS, errors below the JND are rendered imperceptible. The JND is determined empirically as a function of spatial frequency, local texture and local contrast. A distortion measure is developed, making essential use of the JND, for a subband coding environment which attempts to mimic the subjective evaluation effects of the HVS. This distortion measure employs a weighted squared-error metric, where the weighting depends upon the JND value at each pixel position. It essentially assigns near-zero distortion to subthreshold errors and approximately squared-error distortion to superthreshold errors. This perceptual distortion measure was incorporated into a previously developed design procedure for entropy-constrained subband coding (ECSBC) schemes based upon training data. We demonstrate that, compared to use of the conventional squared-error distortion, significant improvements in subjective image reconstruction quality can be achieved at low average bit rates using this perceptual distortion measure.

关键词： image coding Distortion measurement Humans Frequency Training data image reconstruction HDTV Rate-distortion Vector quantization systems engineering and theory

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