In this paper, we propose an integrated robustmultipledescriptioncoding (MDC) scheme for compressed still images over error-prone channels with both packet loss and random bit errors. multipledescriptions are firs...
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In this paper, we propose an integrated robustmultipledescriptioncoding (MDC) scheme for compressed still images over error-prone channels with both packet loss and random bit errors. multipledescriptions are first generated independently by using multipledescription scalar quantizer (MDSQ). To achieve an excellent error resilient capability for each description, multiple bitstreams are then generated based on wavelet trees along the spatial orientations. The spatial orientation trees in the wavelet domain are individually encoded using SPIHT. Error propagation is thus limited within each bitstreams. However, synchronization words are usually needed to avoid error propagation across multiple independent bitstreams. In order to maintain high compression efficiency robust synchronization, we adopt error resilient entropy coding (EREC) to re-organize these variable-length bitstreams into fixed-length data slots before multiplexing and transmission. Therefore, the synchronization of the start of each bitstream can be automatically obtained at the receiver. Finally, to alleviate the devastating image degradation resulted from errors in the beginning of the bitstreams, we propose an error concealment technique to both constrain the EREC/MDC decoding and post-process the decoded wavelet coefficients. With analysis and experimental results, we have demonstrated how each of these components has contributed to the overall robustness of the proposed transmission of compressed images over wireless channels. (c) 2008 Published by Elsevier Inc.
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