WAVELET VIDEO CODING WITH LADDER STRUCTURES AND ENTROPY-CONSTRAINED QUANTIZATION

A subband decomposition using wavelet filters has become an effective basis for image compression, The use of a ladder structure for the sub band filtering provides a fast implementation and allows the system to be useful at video rates, A system is proposed that provides good qua lity video for moderate motion, roughly common intermediate format-f 0 -t(CIF-) sized images at bit rates under 500 kb/s, and for teleconfere ncing scenes at bit rates from 180 kb/s to below 128 kb/s (basic rate ISDN). The system uses subband coding, a modified version of H.261, an d entropy-constrained quantization to achieve the desired bit rate and image quality.