Hybrid Joint Source Channel Decoding for Progressive JPEG Image Transmission

In this paper, we combine two Joint Source Channel Decoding (JSCD) approaches and apply them to progressive JPEG image transmission. The first JSCD approach consists of optimizing the allocation of the channel code-rates to the different layers of the JPEG image, and is commonly referred as Unequal Error Protection (UEP). The second JSCD strategy exploits a priori probabilities obtained from source statistics as well as the residual redundancy of the source to improve channel decoding. Additionally, we propose an error resilient sub-categorization scheme for the DC layer so as to reduce the effect of the channel-induced distortion. The hybrid JSCD scheme is implemented with Rate Compatible Punctured Turbo Codes and also with the bandwidth efficient Rate Compatible Punctured Turbo Trellis Coded Modulation. Gains of over 10 dB in PSNR are obtained with the hybrid JSCD scheme as compared to a conventional JPEG image transmission scheme.