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Data Compression Conference (DCC 2001)

作者： Aggarwal, A Regunathan, SL Rose, K Univ Calif Santa Barbara Dept Elect & Comp Engn Santa Barbara CA 93106 USA

ISBN: (纸本)0769510310

In this paper, we derive an asymptotically optimal multi-layer coding scheme for entropy-coded scalar quantizers (SQ) that minimizes the weighted mean-squared error (WMSE). The optimal entropy-coded SQ is non-uniform in the case of WMSE. The conventional multi-layer coder quantizes the base-layer reconstruction error at the enhancement-layer, and is sub-optimal for the WMSE criterion. We consider the compander representation of the quantizer, and propose to implement scalability in the compressed domain. We show that such a multi-layer coding system achieves the operational rate-distortion bound given by the nun-scalable entropy-coded SQ, at the limit of high resolution. Simulation results for a synthetic memoryless Laplace source with mu -law companding are presented for various values of layer rates. Substantial gains are also achieved on the "real-world" sources of audio signals, when the optimal multi-layer approach is applied to a two-layer scalable MPEG-4 Advanced Audio Coder.

关键词： Mean square error entropy coding quantizer Optimal audio signals minimum Scalability Scalable coding quadratic errors Weighted Average asymptotic audio coder INHOMOGENITIES

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Instantaneously reversible Golomb-Rice codes for robust image coding

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2001年第11期E84A卷 2939-2945页

作者： Guo, ML Hasegawa, M Kato, S Miyamichi, J Utsunomiya Univ Grad Sch Engn Dept Prod & Informat Sci Utsunomiya Tochigi 3218585 Japan Utsunomiya Univ Fac Engn Utsunomiya Tochigi 3218585 Japan

Reversible variable length codes (RVLCs), which make instantaneous decoding possible in both forward and backward directions, are exploited to code data stream in noisy enviroments. Because there is no redundancy in code words of RVLCs, RVLCs are suitable for very low bit-rate video coding. Golomb-Rice code, one of variable length code for infinite number of symbols, is widely used to encode exponentially distributed non-negative integers. We propose a reversible variable length code by modifying Golomb-Rice code, which is called parity check reversible Golomb-Rice code and abbreviated to P-RGR code. P-RGR code has the same code length distribution as GR code but can detect one-bit error in any arbitrary position of the code stream. The sets of P-RGR code words in both directions are identical so that they can be constructed by nearly the same algorithm. Furthermore, this paper also gives a general construction method for all instantaneously decodable RGR codes.

关键词： entropy coding error detection reversible variable length codes

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Fractal image coding combined with subband decomposition

Fractal image coding combined with subband decomposition

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IEEE International Conference on Electronics, Circuits and Systems (ICECS)

作者： K. Sawada S.-Y. Nagai E. Nakamura Aichi Institute of Technology Toyota Aichi Japan

In order to improve the performance of fractal image coding, this paper proposes a new coding scheme which is combined with subband image decomposition. In the proposed scheme, an input image is first decomposed to low and high resolution components by subband decomposition. The fractal block coding with adaptive range block size is performed only for the lowest resolution component. On the other hand, direct quantization and entropy coding are carried out for the other resolution components. The residual difference between reconstructed and original lowest resolution components is also quantized and entropy coded in order to enhance the coding performance. The computer simulation results show that the proposed coding scheme gives higher SNR (signal-to-noise ratio) values and better reconstructed image qualities compared to the conventional fractal block coding scheme.

关键词： Fractals Image coding Block codes Signal resolution Image reconstruction Image decomposition Image resolution Quantization entropy coding Computer simulation

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Fast adaptive encoder for bi-level images

Fast adaptive encoder for bi-level images

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Data Compression Conference (DCC)

作者： H.S. Malvar Microsoft Research Limited Redmond WA USA

ISBN: (纸本)0769510310

We present a new bi-level image compression coder that does not use arithmetic encoding, but whose performance is close to that of state-of-the-art coders such as JBIG, JBIG-2, and JB2. The proposed bi-level coder (BLC) uses two simple adaptation rules: the first to compute context-dependent probability estimates that control a pixel prediction module, and the second to adjust a run-length parameter in a run-length-Rice (RLR) coder. That's contrary to the usual approach where the context-dependent probability estimate controls both pixel prediction and adaptive entropy coding. Due to its simplicity, in many applications BLC may be a better choice than JBIG or JBIG-2.

关键词： Image coding Arithmetic Programmable control Adaptive control Pixel Pattern matching Scanning probe microscopy Error correction codes entropy coding Statistics

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Lossless image data sequence compression using optimal context quantization

Lossless image data sequence compression using optimal conte...

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Data Compression Conference (DCC)

作者： S. Forchhammer Xiaolin Wu J.D. Andersen Department of Telecom Technical University of Denmark Denmark Department of Computer Science University of Western Ontario London ONT Canada

ISBN: (纸本)0769510310

Context based entropy coding often faces the conflict of a desire for large templates and the problem of context dilution. We consider the problem of finding the quantizer Q that quantizes the K-dimensional causal context C/sub i/=(X(i-t/sub 1/), X(i-t/sub 2/), ..., X(i-t/sub K/)) of a source symbol X/sub i/ into one of M conditioning states. A solution giving the minimum adaptive code length for a given data set is presented (when the cost of the context quantizer is neglected). The resulting context quantizers can be used for sequential coding of the sequence X/sub 0/, X/sub 1/, X/sub 2/, .... A coding scheme based on binary decomposition and context quantization for coding the binary decisions is presented and applied to digital maps and /spl alpha/-plane sequences. The optimal context quantization is also used to evaluate existing heuristic context quantizations.

关键词： Image coding Quantization Algorithm design and analysis Adaptive coding Context modeling Telecommunications entropy coding Costs Source coding Random sequences

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An adaptable binary entropy coder

An adaptable binary entropy coder

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Data Compression Conference (DCC)

作者： A. Kiely M. Klimesh Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA

ISBN: (纸本)0769510310

We present a novel entropy coding technique which is based on recursive interleaving of variable-to-variable length binary source codes. The encoding is adaptable in that each bit to be encoded may have an associated probability estimate which depends on previously encoded bits. The technique may have advantages over arithmetic coding. The technique can achieve arbitrarily small redundancy, and admits a simple and fast decoder. We discuss code design and performance estimation methods, as well as practical encoding and decoding algorithms.

关键词： Decoding Arithmetic Encoding entropy coding Propulsion Laboratories Space technology Postal services Interleaved codes Algorithm design and analysis

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Signal processing using LUT filters based on hierarchical VQ

Signal processing using LUT filters based on hierarchical VQ

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： R.L. De Queiroz P. Fleckenstein Xerox Corporation Webster NY USA Center for Imaging Science Rochester Institute of Technology Rochester NY USA

Vector quantization (VQ) is a powerful tool in signal processing. Hierarchical VQ (HVQ) is a method to implement VQ completely based on look-up tables (LUT). In HVQ, both encoders and decoders are inherently simple and fast, since there are no searches over codebooks. We introduce an overlapped HVQ (OHVQ) method, in which the number of samples is preserved after each HVQ stage. After the last stage, each OHVQ code in a particular location in the signal maps to a block (vector) which approximates that neighbourhood in the original sequence. For this reason, OBVQ is used as a basis to create a LUT-based filter, ie, a spatial signal processor with very fast implementation. Preliminary analysis and image processing examples are shown demonstrating the efficiency of the proposed method.

关键词： Signal processing Table lookup Image coding Vector quantization Image reconstruction entropy coding Pixel Information filtering Information filters Decoding

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Clustering context properties of wavelet coefficients in automatic modelling and image coding

Clustering context properties of wavelet coefficients in aut...

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International Conference on Image Analysis and Processing

作者： J. Lehtinen J. Kivijarvi Turku Center for Computer Science Turku Finland

An algorithm for automatic modelling of wavelet coefficients from context properties is presented. The algorithm is used to implement an image coder, in order to demonstrate its image coding efficiency. The modelling of wavelet co-efficients is performed by partitioning the weighted context property space to regions. Each of the regions has a dynamic probability distribution stating the predictions of the modeled co-efficients. The coding performance of the algorithm is compared to other efficient wavelet-based image compression methods.

关键词： Wavelet coefficients Context modeling Image coding Quantization Clustering algorithms Partitioning algorithms Wavelet transforms Probability distribution Continuous wavelet transforms entropy coding

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Robust image transmission based on wavelet tree coding and EREC

Robust image transmission based on wavelet tree coding and E...

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IEEE International Conference on Image Processing

作者： Lei Cao Chang Wen Chen Department of Electrical Engineering University of Missouri Columbia Columbia MO USA

We propose a robust image transmission scheme based on wavelet tree coding and error resilient entropy coding (EREC). After the wavelet decomposition, the coefficients are re-arranged into wavelet trees according to their spatial representation. Each wavelet tree is coded independently so that the scheme is essentially a block-based coding in the spatial domain. Since the self-similarity across subbands is preserved, a high source coding efficiency can be achieved. EREC is then adopted to enhance the error resilience capability of the compressed bitstream. At the receiving end, the automatic re-synchronization of each block is obtained. Furthermore, the bits impacted by the error propagation are more likely located in the low bit-layers so that the resultant degradation is less severe in terms of PSNR. Experimental results show that this proposed scheme can achieve a good error resilient performance.

关键词： Robustness Image communication Image coding Source coding Resilience entropy coding PSNR Channel coding Wavelet coefficients Discrete cosine transforms

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Joint and tandem source-channel coding with delay constraints

Joint and tandem source-channel coding with delay constraint...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Jongtae Lim D.L. Neuhoff EECS Department University of Michigan Ann Arbor MI USA

Two common source-channel coding strategies, joint and tandem, are compared on the basis of distortion vs. delay by analyzing specific representatives of each when transmitting analog data samples across a binary symmetric channel. Channel-optimized transform coding is the joint source-channel coding strategy; transform coding with Reed-Solomon coding is the tandem strategy. For each strategy, formulas for the mean-squared error and delay are found and used to minimize distortion subject to a delay constraint, for data modeled as Gauss-Markov. The results of such optimizations suggest there is a threshold such that when the permissible delay is above this threshold, tandem coding is better, and when below the threshold, channel-optimized transform coding is better.

关键词： Transform coding Gaussian processes Channel coding Quantization Robustness Reed-Solomon codes entropy coding Gaussian channels Delay systems Random processes

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