Triangular active mesh for motion estimation

This paper introduces a motion estimation tool based on triangular active mesh. This tool can be used to model the deformation of various kinds of objects, especially frames and arbitrarily shaped regions known as video object planes (VOPs) in the MPEG-4 context. In the latter case, a polygon approximation of the region is performed in order to define border nodes and to triangulate the whole considered domain. Object motion is represented by a piecewise affine transformation whose coefficients are estimated by means of motion estimation of triangle vertices. Within the context of very low bit-rate coding, this tool appears to be useful for image prediction, temporal interpolation and may achieve the optimal sharing between motion and error information encoding. Simulations show that the proposed motion estimation tool provides higher PSNR than the classical block matching algorithm. (C) 1997 Published by Elsevier Science B.V.