Robust image transmission based on wavelet tree coding, error resilient entropy coding, and error concealment

Abstract

A scheme with three key components including wavelet tree coding, error resilient entropy coding (EREC), and error concealment is proposed for robust image coding and transmission over noisy channels. First, we individually encode the spatial-orientation trees in the wavelet domain using the algorithm of set partitioning in hierarchical trees (SPIHT). Error propagation is thus limited because multiple independent bit streams are generated. Meanwhile, a high source coding efficiency is also preserved because the self-similarity property in each wavelet tree remains intact. Next, we use EREC to reorganize these variable-length bit streams into fixed-length data slots before multiplexing and transmission. Therefore, the synchronization of the start of each bit stream can be automatically obtained at the receiver. Finally, to alleviate the possible catastrophic image degradation that may result from errors in the beginning of the bit streams, we propose an error concealment technique to constrain the EREC decoding as well as to postprocess the decoded wavelet coefficients. As a result of the error concealment, the EREC decoding complexity is reduced and the reconstructed image quality is significantly improved. Experimental results demonstrate an excellent error resilient performance of the proposed scheme.