Digital Image Compression

Several variations on the popular motion-compensated interframe block-coding schemes are proposed. They are devised to handle each image block with a different parameter and/or algorithm based on the contents of that individual block. These adaptive techniques are introduced to reduce the coding bit rate and to improve the reconstructed picture visual quality. 

They may be used in motion-compensation, in image block classification as well as in compressing the (differential) image pels. We describe three adaptive schemes in this paper: (1) adaptive block-size motion compensation and coding, (2) multiple-transform coding, and (3) DCT and cluster (pel-domain) hybrid coding. The complexity and performance limitation issues of these adaptive schemes are also briefly discussed.