An MPEG-4 facial animation parameters generation system
We present a method for generating MPEG-4 FAPs (facial animation parameters) from a video sequence of a talking head. The method includes a render unit that animates a face based on a set of FAPs. The render unit provides feedback to the FAP generation process as guidance toward an optimal set of FAPs. Our optimization process consists of minimizing a penalty function, which includes a matching function and a few barrier functions. The matching function compares how well an animated face matches with the original face. Each barrier function indicates the level of distortion from a normal looking face for a certain part of a face, and advises the optimizer. Unnecessary FAPs are eliminated and the search is partitioned to speed up the optimization process. Three different search techniques, steepest descent method, linear search method, and cyclic coordinates method are applied to derive an optimum.