Optimal Adaptive Multistage Image Transform Coding

Adaptive multistage image transform coding is discussed and an optimal method is introduced for bit allocation. The optimality is in the sense of minimizing the mean square reconstruction error with a given total number of bits and a given number of stages. The statistics of the coefficients in different stages and marginal analysis are used to optimize the division of the total number of bits among the stages. Experimental results indicate that, with two stages, more than 14% improvement for one clan and more than 11076 improvement for multiclasses is achieved in mean square reconstruction error over one-stage image transform coding. Higher improvements are achieved with three stages. The reconstructed images with multistage coding are subjectively much more preferable than the reconstructed Images with one-stage coding.