A major problem in object oriented video coding and MPEG-4 is the encoding of object boundanes. Traditionally, and within MPEG-4, the encodingof shape and textureinformationare separate steps (the extraction of shape is not consideredby the standards). In this paper, we present a vertex-based shape coding method which is optimal in the operationalrate-dstortion sense and takesinto account the textureinformationof the videoframes. Thls is accomplishedby utilizinga variable-widthtoleranceband which is proportional to the degree of trust in the accuracy of the shape information at that location. Thus, in areas where the confidencein the estimation of the boundary is not high andor coding errors in the boundary will not affect the application (object oriented coding, MPEG-4, etc.) significantly, a larger boundary approximationerror is allowed. We present experimentalresults which demonstratethe effectiveness of the proposed a l g o r i h
Lisimachos P. Kondi, Gerry Melnikov, Aggelos K. Ka