AN ERROR RESILIENT AND MEMORY EFFICIENT SCHEME FOR WAVELET IMAGE CODING

SetPartitioning in Hierarchical Trees (SPIHT) is a state-of-art zero-tree based image coder with excellent rate-distortion performance in the noise free environments. However in presence of noise they are extremely sensitive to the bit errors. Even a single bit error may lead a substantial degradation in the quality. Our investigations reveal that the use of three linked lists in SPIHT increases the inter-bitplane dependencies of bits and therefore causes the errors to propagate down the bitstream. In this paper we propose a modified coder which uses only a single list. The list is initialized, processed and exhausted within each bit-plane, thereby removing dependencies of inter-plane bits. The proposed coder is known as Single List SPIHT (SL-SPIHT) image coder. Additionally, this coder is memory efficient as compared to the SPIHT. Simulation results show that under the same channel conditions, SL-SPIHT can improve the quality of reconstructed image by 5-6 dB compared to that of SPIHT.