Irregular triangular mesh representation based on adaptive control point removal

Several new approaches are being investigated in conjunction with the low bit rate coding, such as MPEG-4, to overcome the limitation imposed by block-based image compression. One solution is to use 'warping' prediction (or spatial transformation) based on a set of control points where one of the most important issues is how to adequately place the control points not destroying salient features such as edges and corners. In this paper, we propose a new image representation scheme based on irregular triangular mesh structure in which, considering the salient features, a considerably reduced number of control points are adaptively selected out of initial uniformly distributed control points. A new criterion based on local representation error is defined to be used in successive control point removal exploiting global image features, thus providing better image representation. Computer simulation has shown that the proposed scheme gives significantly improved image representation performance compared with the conventional scheme based on regular meshes in both objective and subjective qualities.