Pixel level interleaving schemes for robust image communication

Abstract

Interleaving schemes have proven to be an important mechanism in reducing the effect of network errors on image transmission. Current interleaving schemes spatially decorrelate neighboring image blocks by putting them into packets that are a long way apart from each other in the transmission sequence. Most of the existing schemes, while achieving good performance on random packet losses, do not work well in the case of bursty packet losses. In this paper, we propose two interleaving schemes where the decorrelation process is applied not only at the block level but also at the pixel or coefficient level (i.e. on the information within the blocks) in the compressed domain. The decorrelation is achieved via a k-way shuffle of pixels among the blocks and by using the spatial properties of different space-filling curves, where k depends on the total number of blocks in the image. Our results show that in spite of the decorrelation of coefficients in the triangular interleaving scheme, the compression ratio is within 92% to -98% of JPEG standard compression. We also show that, when compared with existing interleaving schemes, our techniques provide improved image quality and a low mean square error in the transmitted images in the presence of random as well as bursty packet losses in networks.