EDGE-BASED MOTION ESTIMATION AND REGION-BASED CONTOUR TRACING FOR VERY-LOW BIT-RATE VIDEO CODING

A new algorithm for image sequence coding with a very low bit rate and high picture quality is proposed. The proposed coding system is compo sed of interframe and intraframe coding. In the interframe coding, an edge-based motion estimation algorithm is used to find the motion vect or of a moving block instead of using the conventional block-matching algorithm. The edge-based method reduces the entropy of the estimated motion vectors within a frame. Since the motion vectors are usually en coded by entropy coding, bit rate is also reduced. In the intraframe c oding, a region-based algorithm is used to trace the contour of an obj ect and estimate its parameters from a predetermined database of vario us geometric shapes. It can reduce the blocking effect. By testing sev eral image sequences such as ''Miss America'' and ''Claire'' with 10 f rames/s in quarter common intermediate format (QCIF) the proposed codi ng system has about 1 to 2 dBs higher peak SNRs than the H.263 system. (C) 1998 SPIE and IS&T. [S1017-9909(98)01401-9].