Bi-directional synchronization and hierarchical error correction for robust image transmission

In this paper, we present a novel joint source and channel image coding scheme for noisy channel transmission. The proposed scheme consists of two innovative components: (1) Intelligent bi-directional synchronization, and (2) Layered bit-plane error protection. The bi-directional synchronization is able to recover the coding synchronization when any single or even when two consecutive synchronization codes are corrupted by the channel noise. With synchronized partition, unequal error protection for each bit-plane can be designed to suit for a wide range of channel environments. The hierarchical error protection strategy is based on the analysis of bit-plane error sensitivity, aiming at achieving an optimal joint source and channel coding when the compressed image data are transmitted over noisy channels. Experimental results over extensive channel simulations show that the proposed scheme outperforms the approach proposed by Sherwood and Zeger who have reported the best numerical results in the literature.