Abstract: A method and apparatus for human face shape and motion estimation based on integrating optical flow and deformable models is disclosed. The optical flow, constraint equation provides a non-holonomic constraint on the motion of the deformable model. Forces computed from edges and optical flow are used simultaneously. When this dynamic system is solved, a model-based least-squares solution for the optical flow is obtained and improved estimation results are achieved. The use of a 3-D model reduces or eliminates problems associated with optical flow computation. This approach instantiates a general methodology for treating visual cues as constraints on deformable models. The model uses a small number of parameters to describe a rich variety of face shapes and facial expressions.