Subband image coding using entropy-coded quantization over noisy channels

Under the assumption of noiseless transmission the authors develop two entropy-coded subband image coding schemes. The difference between these schemes is the procedure used for encoding the lowest frequency subband: predictive coding is used in one system and transform coding in the other. After demonstrating the unacceptable sensitivity of these schemes to transmission noise, the authors also develop a combined source/channel coding scheme in which rate-compatible convolutional codes are used to provide protection against channel noise. A packetization scheme to prevent infinite error propagation is used and an algorithm for optimal assignment of bits between the source and channel encoders of different subbands is developed. It is shown that, in the presence of channel noise, these channel-optimized schemes offer dramatic performance improvements.<
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