Multiple Description Shifted Lattice Vector Quantization for Progressive Wavelet Image Coding
Multiple description (MD) coding is a promising alternative for robust transmission of information over non-prioritized and unpredictable networks. Furthermore, practical variable-bandwidth channels also require fine grain scalability of the descriptions (bit streams). In this paper, according to the geometrical structure and the special relationship of lattice vector quantizers, a MD quantizer called shifted lattice vector quantization (SLVQ) is employed in MD image coding to realize progressive transmission over unreliable channels. In view of the characteristics of wavelet coefficients in different frequency subbands, besides an appropriate construction of wavelet coefficient vectors, the algorithm of modified zerotree coding is also applied to improve compression performance. Experimental results validate the effectiveness of the proposed scheme with better performance than the other schemes based on MD scalar quantization for progressive transmission.