Subband image coding with optimal intra- and inter-band subband quantization

Significant progress has been made in the theory and design of analysis/synthesis filter banks and in the independent encoding and decoding subsystems. However, by comparison, little attention has been given to the optimal design of subband quantizers in the sense of minimizing the overall average distortion subject to a constraint on the output rate of the subband system. In the paper, necessary conditions for optimal subband quantization are presented. These conditions can be employed to design quantizers that exploit the linear and non-linear dependencies both within and across the subbands, leading to improvement in performance