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Robust Image and Video Transmission Over Spectrally Shaped Channels Using Multicarrier Modulation

IEEE TRANSACTIONS ON MULTIMEDIA 1999年第1期1卷 88-103页

作者： Zheng, Haitao Liu, K. J. Ray Univ Maryland Syst Res Inst College Pk MD 20742 USA Univ Maryland Dept Elect Engn College Pk MD 20742 USA

This paper presents a new parallel transmission framework for reliable multimedia data transmission over spectrally shaped channels using multicarrier modulation. We propose to transmit source data layers of different perceptual importance in parallel, each occupying a number of subchannels. New loading algorithms are developed to efficiently allocate the available resources, e.g., transmitted power and bit rate, to the subchannels according to the source layers they transmit. Instead of making the bit error rate of all the subchannels equal as in most existing loading algorithms, the proposed algorithm assigns different error performance to the subchannels to achieve unequal error protection for different layers. The channel induced distortion in mean-square sense is minimized. We show that the proposed system can be applied nicely to both fixed length coding and variable-length coding. Asymptotic gains with respect to channel distortion are also derived. Numerical examples show that the proposed algorithm achieves significant performance improvement compared to the existing work, especially for spectrally shaped channels commonly used in in ADSL systems.

关键词： Combined source coding and channel modulation entropy coding layered coding multicarrier modulation multimedia transmission spectrally shaped channel subband coding

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Edge-preserving directional regularization technique for disparity estimation of steroscopic images

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 1999年第3期45卷 804-811页

作者： Kim, MH Sohn, KH Yonsei Univ Dept Elect & Comp Engn Seoul 120749 South Korea

Recently, due to the advances in visual technology, three dimensional(3D) imaging systems are becoming popular. One way of stimulating 3D perception is to use stereo pairs, a pair of images of the same scene acquired from different perspectives. Since there is an inherent redundancy between the images of a stereo pair;data compression algorithms should be employed to efficiently represent stereo pairs. Disparity estimation of stereoscopic image is an important stage for the stereo image compression. We propose a new disparity estimation method using a directional regularization technique to preserve edges well for stereoscopic image coding This method smooths disparity vectors in smooth regions and preserves edges ill object boundaries without over-smoothing problem. The experimental results show that the proposed method achieves close matches between a left image and a right image as well as the improved coding efficiency. We use DPCM technique followed by the Huffman entropy, coding for disparity map coding. In addition, the proposed disparity estimation method can be applied to the high-quality intermediate view reconstruction.

关键词： Image coding Image reconstruction Layout entropy coding Image storage Digital TV Data compression Motion pictures Biomedical imaging Surgery

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Lattice vector quantization of wavelet coefficients with perceptual visibility model and hybrid entropy coding

Lattice vector quantization of wavelet coefficients with per...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Wenxing Zheng Hongho Zhu Ziyi Quan Beijing University of Posts and Telecommunications Beijing China

In this paper, a perceptually tuned wavelet image coder is presented. In the wavelet transform domain, wavelet coefficients are quantized using a lattice quantizer, and the resulting lattice points are efficiently losslessly encoded in the framework of quadtree decomposition and hybrid entropy coding. The parameter used by the lattice quantizer is determined from a perceptual model, and is used to confine the quantization noise to a just-notice distortion (JND) or minimally noticeable distortion (MND) when the bitrate budget is tight. Moreover, a perceptually optimized bit allocation algorithm is also investigated. The proposed coder can efficiently remove both statistical redundancy and perceptual redundancy.

关键词： Lattices Vector quantization Wavelet coefficients Image coding Bit rate Discrete wavelet transforms entropy coding Decoding Wavelet domain Wavelet transforms

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High-order context modeling and embedded conditional entropy coding of wavelet coefficients for image compression

High-order context modeling and embedded conditional entropy...

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Asilomar Conference on Signals, Systems & Computers

作者： Xiaolin Wu Department of Computer Science University of Western Ontario London ONT Canada

ISBN: (纸本)0818683163

Much of the progress in wavelet image compression came from better context modeling and entropy coding of quantized wavelet coefficients. In the past few months many papers on the subject were published. They reported rate-distortion performance results that are the best or near the best in the literature. Given seemingly ever smaller improvements on R-D performance with increasing sophistication and complexity of current R-D optimized quantizers and context models of wavelet coefficients, two tantalizing questions are whether there still exists some room for even higher coding efficiency of wavelet image coders, and if so, whether the improvement can be made with an embedded code stream. This paper sheds some lights on, and offers modestly encouraging answers to these questions.

关键词： Context modeling entropy coding Wavelet coefficients Image coding Quantization Shape Rate-distortion Wavelet domain Wavelet transforms Arithmetic

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Classified adaptive prediction and entropy coding for lossless coding of images

Classified adaptive prediction and entropy coding for lossle...

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IEEE International Conference on Image Processing

作者： F. Golchin K.K. Paliwal School of Microelectronic Engineering Griffith University Brisbane QLD Australia

Natural images often consist of many distinct regions with individual characteristics. Adaptive image coders exploit this feature of natural images to obtain better compression results. In this paper, we propose a classification-based scheme for both adaptive prediction and entropy coding in a lossless image coder. In the proposed coder, blocks of image samples (in the PCM domain) are classified to select an appropriate linear predictor from finite set of predictors. Once the predictors have been determined, the image is DPCM coded. A second classification is then performed to select a suitable entropy coder for each block of DPCM samples. These classification schemes are designed using two separate clustering procedures which attempt to minimize the bit-rate of the encoded image. The coder was tested on a set of monochrome images and was found to produce very promising results.

关键词： entropy coding Image coding Image storage Microelectronics Australia Phase change materials System testing Biomedical imaging Satellites Costs

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Context modeling and entropy coding of wavelet coefficients for image compression

Context modeling and entropy coding of wavelet coefficients ...

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

作者： Xiaolin Wu Jian-huo Chen Department of Computer Science University of Western Ontario London ONT Canada Department of Information Engineering Chinese University of Hong Kong New Territories Hong Kong China

ISBN: (纸本)0818679190

In this paper we study the problem of context modeling and entropy coding of the symbol streams generated by the well-known EZW image coder (embedded image coding using zerotrees of wavelet coefficients). We present some simple context modeling techniques that can squeeze out more statistical redundancy in the wavelet coefficients of EZW-type image coders and hence lead to improved coding efficiency.

关键词： Context modeling entropy coding Wavelet coefficients Image coding Wavelet transforms Quantization Wavelet domain Image reconstruction Computer science Streaming media

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Context-based entropy coding of VQ indexes

Context-based entropy coding of VQ indexes

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IEEE International Symposium on Information Theory

作者： Xiaolin Wu Jiang Wen Wai-Yin Ng Department of Information Engineering Chinese University of Hong Kong Hong Kong China

Limited by the inherent computational intractability of vector quantization in dimensions, practical VQ coders all employ signal blocks of rather modest sizes, failing to capture all higher-order statistical dependency. Therefore, context-based, adaptive entropy coding of VQ indexes can significantly reduce the bit rate of VQ coders for a given distortion.

关键词： entropy coding Image coding Bit rate Context modeling Quantization Random processes Pixel Source coding Bayesian methods Computational efficiency

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Fixed length entropy coding for robust video compression

Fixed length entropy coding for robust video compression

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IEEE International Conference on Image Processing

作者： R. Llados-Bernaus R.L. Stevenson Department of Electrical Engineering University of Notre Dame Notre Dame IN USA

entropy coding is a fundamental stage in all video compression algorithms. Variable length entropy codes (VLC) are used in current video codecs. Designed to be employed in noiseless applications, these codes are very sensitive to transmission errors. This paper proposes the use of fixed length entropy codes (FLC) as an alternative to VLC in video compression applications. In noisy transmissions the FLC codes have shown a superior performance compared to VLC schemes with synchronization words.

关键词： entropy coding Video compression Noise robustness Video codecs

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Wavelet coding of image using quadtree representation and block entropy coding

Wavelet coding of image using quadtree representation and bl...

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

作者： Wenxing Zheng Hua Nan Laboratory of TV Technology Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)0818679190

A new efficient image coding scheme, based on quadtree representation and block entropy coding (QRBEC), for encoding the wavelet transform coefficients of images is presented. The property of HVS is also incorporated into the quantization process. In addition, how to flexibly control the quantization level as well as output bitrate of the coder is also investigated. The coding efficiency of the coder is quite competitive with the well-known EZW coder, and requires less computation burden. The proposed coding scheme can also be applied in image sequence coding, resulting in satisfactory performance.

关键词： Image coding entropy coding Quantization Wavelet coefficients Frequency Filters Laboratories TV Wavelet transforms Electronic switching systems

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Novel techniques for speech compression using wavelet transform 11

Novel techniques for speech compression using wavelet transf...

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11th International Conference on Microelectronics (ICM99)

作者： Hosny, NM El-Ramly, SH El-Said, MH Ain Shams Univ Fac Engn Elect & Comm Eng Dept Cairo Egypt

ISBN: (纸本)0780366433

This paper introduces two new techniques for speech compression using Wavelet Transform (WT). The first technique, Zero Wavelet transform(ZWT), eliminates the high frequency coefficients of the wavelet decomposition with energy values below a certain threshold level. The second technique, Average Zero Wavelet Transform (AZWT), in addition to fulfilling the goal of the first technique, it averages the approximate coefficients of the wavelet decomposition. These coefficients are almost constant at higher decomposition levels of the transform. The wavelet coefficients are, then, quantized using Lloyd's algorithm and coded using the entropy coding technique before being transmitted. At the receiver end, the received signal is decoded and dequantized before being processed.

关键词： Discrete cosine transforms Discrete transforms Discrete wavelet transforms entropy coding Frequency Power engineering and energy Speech Testing Wavelet coefficients Wavelet transforms

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