An open problem in source coding theory has been whether the Karhunen-Loeve transform (KLT) is optimal for a system that orthogonally transforms a vector source, scalar quantizes the components of the transformed vect...
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An open problem in source coding theory has been whether the Karhunen-Loeve transform (KLT) is optimal for a system that orthogonally transforms a vector source, scalar quantizes the components of the transformed vector using optimal bit allocation, and then inverse transforms the vector. Huang and Schultheiss (1963) proved that for a Gaussian source the KLT is mean squared optimal in the limit of high quantizer resolution. It is often assumed and stated in the literature that the KLT is also optimal in general for nonGaussian sources. We disprove such assertions by demonstrating that the KLT is not optimal for certain nearly bimodal Gaussian and uniform sources. In addition, we show the unusual result that for vector sources with independent identically distributed Laplacian components, the distortion resulting from scalar quantizing the components can be reduced by including an orthogonal transform that adds intercomponent dependency.
We address the problem of constructing an adaptive arithmetic code in the case where the source alphabet is large and there are lots of different symbols with equal counts of occurrence. For an alphabet of N symbols a...
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We address the problem of constructing an adaptive arithmetic code in the case where the source alphabet is large and there are lots of different symbols with equal counts of occurrence. For an alphabet of N symbols and r distinct symbol weights we describe a code for which the number of operations of encoding and decoding is equal to c log r + c/sub 1/ instead of c log N + c/sub 2/ as in previous arithmetic codes, c, c/sub 1/, c/sub 2/ are constants. When r is small relative to N - which is the case for most practical coding problems on large alphabets - the encoding and decoding speed of the suggested code will be substantially greater than with known methods.
This paper presents a coordinated multiple-substream unequal error protection and error concealment algorithm for SPIHT-coded bitstreams transmitted over lossy channels. In the proposed scheme, we divide the video seq...
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This paper presents a coordinated multiple-substream unequal error protection and error concealment algorithm for SPIHT-coded bitstreams transmitted over lossy channels. In the proposed scheme, we divide the video sequence corresponding to a group of pictures into two sub-sequences in the temporal domain and independently encode each sub-sequence with a 3-D SPIHT algorithm to generate two independent substreams. Each substream is protected by an FEC-based unequal error protection algorithm that assigns unequal forward error correction codes for each substream with bit-plane granularity. The information that is lost during transmission for one substream is estimated at the receiver by using the correlation between the two substreams and the smoothness of the video signal. Simulation results show that the proposed multiple-substream UEP algorithm is simple, fast, and robust in hostile network conditions, and that the proposed error concealment algorithm achieves about 1-3 dB PSNR gain over the case where there is no error concealment at high packet loss rates.
Transmission of compressed images is challenging because the communication channels can be noisy and the compressed bitstreams are sensitive to channel errors. Most of the proposed methods in the literature do not gua...
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Transmission of compressed images is challenging because the communication channels can be noisy and the compressed bitstreams are sensitive to channel errors. Most of the proposed methods in the literature do not guarantee the quality of the received image over noisy channels. We propose an ARQ-based diversity system as a solution, in which the use of the diversity system avoids the problems when one or some channels get congested, and the ARQ scheme guarantees the quality of the received image. A specific ARQ-based diversity system is designed for transmission of images compressed using EZW (embedded zerotree wavelet). Experiments performance results are shown.
A global bit-allocation algorithm for wireless video communication is presented in this paper. Specifically, a generalized distortion-rate model at macroblock level is first proposed, which reflects the relation among...
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A global bit-allocation algorithm for wireless video communication is presented in this paper. Specifically, a generalized distortion-rate model at macroblock level is first proposed, which reflects the relation among the source coding rates, channel coding rates and the end-to-end distortion consisting of quantization distortion and channel loss distortion compensated by error concealment. Based on this model, a classification algorithm with modified equal mean normalized standard deviation is applied for optimal bit-allocation. Simulation results manifest that the proposed algorithm outperforms conventional bit allocation schemes both in terms of rate-distortion framework and perceptual evaluation.
The Karhunen-Loeve transform is a key element of many signal processing tasks, including classification and compression. In this paper, we consider distributed signal processing scenarios with limited communication be...
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The Karhunen-Loeve transform is a key element of many signal processing tasks, including classification and compression. In this paper, we consider distributed signal processing scenarios with limited communication between correlated sources, and we investigate a distributed Karhunen-Loeve transform (KLT). In particular, a partial (where only a subset of sources are observed) and a conditional KLT (where some sources act as side information) are posed and solved in a rate-distortion sense. The partial KLT leads to an original bit allocation problem, while the conditional KLT leads to a Wyner-Ziv solution which is separable at the sources. These two cases can be seen as extreme cases of a distributed KLT.
This paper addresses the problem of optimal packetization for a fine granularity scalable (FGS) bitstream. A very general performance metric for streaming FGS bitstreams over packet erasure networks is first defined a...
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ISBN:
(纸本)0780374487
This paper addresses the problem of optimal packetization for a fine granularity scalable (FGS) bitstream. A very general performance metric for streaming FGS bitstreams over packet erasure networks is first defined and analyzed. Then three packetization strategies, namely baseline packetization, binary-tree packetization and optimal packetization are presented, justified and compared. Finally, some experimental results are presented to demonstrate the effectiveness of the packetization schemes.
This paper suggests some basic rules about designing stable digital ASIC in HDL. These suggestions cover the items in the source coding, synthesis, simulation and testing processes in order for function stability, are...
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ISBN:
(纸本)0780374886
This paper suggests some basic rules about designing stable digital ASIC in HDL. These suggestions cover the items in the source coding, synthesis, simulation and testing processes in order for function stability, area minimization and speed satisfaction. All of these are explained with simple examples so their advantages are obvious.
We consider the multiple access source coding (MASC) problem (also known as the Slepian-Wolf problem) for situations where the joint source statistics are unknown a priori. Since neither encoder receives information a...
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We consider the multiple access source coding (MASC) problem (also known as the Slepian-Wolf problem) for situations where the joint source statistics are unknown a priori. Since neither encoder receives information about the joint source statistics, we allow an asymptotically negligible amount of communication between the encoders. We prove the existence of universal 2-encoder linked MASCs (LMASCs) with rates approaching the Slepian-Wolf bound, demonstrate the tightness of this bound, and calculate the rate of convergence of the proposed universal LMASC. The result generalizes to M>2 encoders. We also consider scenarios where the number of bits passed between the system encoders is allowed to grow linearly in the code dimension; in these scenarios one encoder can act as a conduit for the flow of another encoder's information.
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