Interframe hierarchical vector quantization
An interframe coding scheme for the transmission of image sequences at bit rates below 0.2 bits per pixel is presented. The proposed scheme is called an interframe hierarchical (quadtree) vector quantizer. A regular decomposition quadtree method is used to segment the interframe differential signal into homogeneous regions of different block size. Small blocks representing high-contrast moving boundaries known as the impulsive component of the difference signal are vector-quantized. Large blocks typically representing smooth regions of the image are encoded by the local sample mean of the region. Experimental results are presented, confirming that the system can encode image sequence scenes at bit rates below 0.2 bit per pixel per frame. A comparison of the interframe hierarchical vector quantization system and an interframe mean reconstructed quadtree method is presented.<<ETX>>