THE OPTIMAL TRANSFORM OF MOTION-COMPENSATED FRAME DIFFERENCE IMAGES IN A HYBRID CODER

Using the statistical model proposed by Chen and Pang [4], various sta tistical characteristics of the motion compensated frame difference (M CFD) images are derived. It is shown that the optimum KLT for the MCFD images is in fact identical to that of the original image sequence in intraframe mode, and that the DCT remains near optimal. The study thu s provides insights into the working of the MPEG and H.261 coders, inc luding the justification for using the same DCT for both intra- and in terframe modes. Experiments on standard image sequences confirm the ac curacy of the statistical model.