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IEEE Asia-Pacific Conference on Circuits and Systems

作者： W. Asdornwised S. Jitapunkul Digital Signal Processing Research Laboratory Department of Electrical Engineering Chulalongkom University Bangkok Thailand

Proposes a simplistically universal lossless image codec (SULIC). A conceptually simple approach may be described as follows. The image is decomposed by reversible integer wavelet transforms (RIWT) as recursive prediction processes. To exploit the remained correlations within the intra-subband, the subband coefficients are scanned corresponding to their prediction properties. For example, in detailed (hh) subbands, we use space filling curves (SFC) which is suitable to use with context based entropy coding. Since no context between subbands has been used In this work, we use prediction with partial matching (ppm) encoder in order to compensate for inter-subband contexts. From the experimental results, the performance of SULIC is comparable to JPEG-LS and SPIHT with lower complexity.

关键词： Image coding Wavelet transforms Filling Pixel entropy coding Decorrelation Arithmetic Variable speed drives Digital signal processing Laboratories

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An iterative algorithm for context selection in adaptive entropy coders

An iterative algorithm for context selection in adaptive ent...

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IEEE International Conference on Image Processing

作者： J. Vaisey Tong Jin School of Engineering Science Simon Fraser University Burnaby Canada

Context-based adaptive entropy coding is an essential feature of modern image compression algorithms; however, the design of these coders is non-trivial due to the balance that must be struck between the benefits associated with using a large number of conditioning classes, or contexts, and the penalties resulting from data dilution. The problem is especially severe when coding small sub-images where the amount of data available is small. In this paper, we propose an iterative algorithm that begins with a large number of conditioning classes and then uses a clustering procedure to reduce this number to a desired value. This method is in contrast to the more usual approach of defining contexts in an ad-hoc manner. Experiments are conducted on synthetic data sources having varying amounts of memory, as well as on the sub-images resulting from a wavelet decomposition of an image. The results show that our approach to context selection is effective and that the algorithm automatically learns the structure of the data. This technique could be applied to improve the performance of both image and video coders.

关键词： Iterative algorithms Image coding entropy coding Arithmetic Frequency estimation Modems Algorithm design and analysis Video compression Code standards Partitioning algorithms

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The half a bit loss of robust source/channel codebooks

The half a bit loss of robust source/channel codebooks

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IEEE (first ITW conference of the year) Information Theory Workshop (ITW)

作者： R. Zamir Department of Electrical Engineering -Systems Tel-Aviv University Israel

We consider the problem of choosing robust codebooks for rate-distortion relative to difference distortion measures, and for capacity-cost relative to additive noise channels. We define an information theoretic formula for the min-max redundancy associated with robust random source codes, and similarly for the loss of robust random channel codes. We then show that this min-max performance can be approached by structured, dithered lattice codebooks. Applications to coding with side information are discussed.

关键词： Rate-distortion Noise robustness Distortion measurement Maximum likelihood decoding Additive noise Lattices Modulation coding entropy coding Redundancy Channel capacity

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Fuzzy coded trellis quantization

Fuzzy coded trellis quantization

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IEEE Region 8 International Symposium on Video/Image Processing and Multimedia Communications (EURASIP)

作者： D. Gleich P. Planinsic Z. Cucej Faculty of electrical engineering and computer science Maribor Slovenia

In this paper we propose an image compression algorithm based on embedded trellis quantization and inventive fuzzy context based modeling (TCQFCB). The indices produced by trellis-coded quantization are adaptively arithmetically coded, bit plane by bit plane. The fuzzy logic is used to assign the probability of the coded symbol for an arithmetic coder. The probability of the coded bit depends on the previous coded bits. The fuzzy logic is used in order to attribute the highest possible probability of the coded bit. The performance of the proposed method is comparable with the state-of-the-art methods.

关键词： Quantization Context modeling Arithmetic Fuzzy logic Image coding Probability Computer science Art entropy coding Optimization methods

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A two-pass optimal motion-threading technique for 3D wavelet video coding

A two-pass optimal motion-threading technique for 3D wavelet...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Lin Luo Feng Wu Shipeng Li Zhenquan Zhuang Ya-Qin Zhang University of Science and Technology Hefei Anhui China University of Science and Technology of China Hefei Anhui P.R. China Microsoft Research Asia Phoenix-Scottsdale AZ USA

ISBN: (纸本)0780374487

Motion-threading is a novel technique that can efficiently incorporate motion information into 3D wavelet video coding. By utilizing a shape adaptive wavelet transform along with the motion-threading technique, 3D wavelet video coding can greatly outperform MPEG-4 for those sequences with simple motion. Since the motion estimation used in the threading process only considers the correlation of adjacent frames in signal magnitude, a large number of short threads are present in the existing motion-threading technique. As a result, the coding efficiency of the 3D motion-threading wavelet coding is far lower than that of MPEG-4 for those sequences with complex motion. This paper contributes a two-pass optimal motion-threading (TOMTH) technique for the 3D wavelet video coding. Both the correlation in signal magnitude and the number of threads are considered by using a new criterion of motion estimation. TOMTH effectively reduces the number of motion threads, meanwhile maintaining considerable accuracy in aligning frames. Experimental results show that the 3D wavelet video coding with the proposed TOMTH technique can achieve consistent good performance in various sequences.

关键词： Video coding Yarn Wavelet transforms MPEG 4 Standard Motion estimation Asia Shape entropy coding Scalability Signal processing

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Optimized compression of triangle mesh geometry using prediction trees

Optimized compression of triangle mesh geometry using predic...

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International Symposium on 3D Data Processing Visualization and Transmission

作者： B. Kronrod C. Gotsman Computer Science Department Technion-Israel Institute of Technology Haifa Israel

Almost all triangle mesh compression algorithms to date are driven by the mesh connectivity code. The geometry code usually employs a straightforward prediction method applied to the vertex sequence as dictated by the connectivity code. This generates a suboptimal geometry code, which results in significant loss in code efficiency, since the geometry dominates the mesh information content. The paper proposes a manifold mesh code which optimizes the geometric component, at the slight expense of the connectivity code. This mesh geometry code is shown to be up to 50% more compact than the state-of-the-art geometry code of Touma and Gotsman (1998), especially for models with non-smooth geometry, such as CAD models.

关键词： Mesh generation Solid modeling Prediction methods Information geometry Computational geometry Computer science Compression algorithms Decoding Distortion measurement entropy coding

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An UVLC encoder architecture for H.26L

An UVLC encoder architecture for H.26L

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Tu-Chih Wang Hung-Chi Fang Wei-Min Chao Hong-Hui Chen Liang-Gee Chen DSP/IC Design Laboratory EE Department National Taiwan University Taiwan

ISBN: (纸本)0780374487

Variable length code (VLC) is widely used in various compression applications. The latest under development video coding standard, H.26L, uses a unique pattern VLC code called UVLC in the test model document. In this paper, an UVLC encoder architecture is proposed to meet the requirements of TML8. This architecture is composed of a code splitter, a first 1 detector, a shifter, a length accumulator, and a code mux/output. A modified code number technique and auto self alignment technique are used to simplify the architecture. By using these techniques, the size of this architecture is much smaller when compared to traditional VLC encoders. It has been synthesized in a 0.35 /spl mu/m cell library. The size of this architecture is 980 gates while critical path is less than 6 ns.

关键词： entropy coding Video coding Testing Decoding Parallel architectures Chaos Digital signal processing Application specific integrated circuits Laboratories Code standards

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Conditional entropy coding of VQ indexes for image compression

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IEEE TRANSACTIONS ON IMAGE PROCESSING 1999年第8期8卷 1005-1013页

作者： Wu, XL Wen, J Wong, WH Univ Western Ontario Dept Comp Sci London ON N6A 5B7 Canada Chinese Univ Hong Kong Dept Informat Engn Shatin NT Peoples R China Univ Calif Los Angeles Dept Stat Los Angeles CA 90095 USA

Block sizes of practical vector quantization (VQ) image coders are not large enough to exploit all high-order statistical dependencies among pixels. Therefore, adaptive entropy coding of VQ indexes via statistical context modeling can significantly reduce the bit rate of VQ coders for given distortion, Address VQ was a pioneer work in this direction. In this paper we develop a framework of conditional entropy coding of VQ indexes (CECOVI) based on a simple Bayesian-type method of estimating probabilities conditioned on causal contexts. CECOVI is conceptually cleaner and algorithmically more efficient than address VQ, with address-VQ technique being its special case, It reduces the bit rate of address VQ by more than 20% for the same distortion, and does so at only a tiny fraction of address VQ's computational cost.

关键词： address VQ context modeling of images entropy coding joint probability estimation vector quantization

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A lossless image coder with context-based minimizing MSE prediction and entropy coding

A lossless image coder with context-based minimizing MSE pre...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： M. Kwon Hyo Joon Kim Choong Woong Lee Sang Uk Lee Institute of New Media and Communications Seoul National University Seoul South Korea

In this paper, a novel gray-scale lossless image coder, based on context-based minimizing mean squared error (MMSE) prediction and entropy coding, is proposed. The proposed algorithm consists of a prediction stage and an entropy coding stage. To obtain the context of prediction, classification of directional edges is employed, which characterizes two-dimensional image behaviors, such as edge and smooth region. Based on the context model, adaptive DPCM prediction coefficients are obtained in the MMSE sense. The MMSE method based on a context-by-context basis decorrelates the neighboring pixels very effectively in the prediction stage. In the entropy coding stage, the context modeling techniques also provide an improved coding gain. To exploit the statistical redundancy still remaining in the residual image, many contexts are preset in the entropy coding stage, and merged into a small number of contexts for complexity reduction. From experimental results, it is found that the proposed lossless coding scheme slightly outperforms the CALIC which is known to achieve the highest compression ratio in entropy coding.

关键词： entropy coding Context modeling Image coding Predictive models Merging Pixel Electronic mail Gray-scale Prediction algorithms Decorrelation

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Joint image/video compression and encryption via high-order conditional entropy coding of wavelet coefficients

Joint image/video compression and encryption via high-order ...

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IEEE International Conference on Multimedia Computing and Systems (ICMCS)

作者： Xiaolin Wu P.W. Moo Department of Computer Science University of Western Ontario London ONT Canada

As the Internet and multimedia systems grow in size and popularity, compression and encryption of image and video data are becoming increasingly important. However, independent compression and encryption is too slow for many multimedia applications. This paper presents a new joint compression and encryption method for images and videos that uses high-order conditional entropy coding of wavelet coefficients to facilitate encryption. As a result, state-of-the-art compression and significantly enhanced security are achieved, with no extra computational complexity.

关键词： Video compression Cryptography entropy coding Image coding Streaming media Arithmetic Wavelet coefficients Data security Computer science Internet

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