Jointly optimal coding of texture and shape

A major problem in object oriented video coding and MPEG-4 is the encoding of object boundaries. Traditionally, and within MPEG-4, the encoding of shape and texture information are separate steps (the extraction of shape is not considered by the standards). We present a vertex-based shape coding method which is optimal in the operational rate-distortion sense and takes into account the texture information of the video frames. This is accomplished by utilizing a variable-width tolerance band which is proportional to the degree of trust in the accuracy of the shape information at that location. Thus, in areas where the confidence in the estimation of the boundary is not high and/or coding errors in the boundary will not affect the application (object oriented coding, MPEG-4, etc.) significantly, a larger boundary approximation error is allowed. We present experimental results which demonstrate the effectiveness of the proposed algorithm.