Research On The Technology Of The Parameterized Facial Expression Animation Based On FFD

Facial modeling and animation has been developed into 2 big categories and several small types integrated together since Parke created the first 3D facial animation in 1972. This thesis is the fellow study of the Computer Aided Glasses Design System. Improved the existent Local Control Model, we present a parameterized deformable facial model to suite the expression animation, and use global muscle deformation and local free-form deformation, implement a 3D facial animation system.We create a parameterized deformable facial model based on the structure of the human face. The model is composed of 3 parts: skin mesh, muscle and skull. To simulating the skin, we define the nonlinear spring and the ERS (Edge Repulsion Spring) on the elastic skin mesh. The ERS is used for preventing the collapse of skin. The muscle is defined by the muscle vector based on the crucial AUs in the FACS, and the skin mesh will divide into areas by the influence of the muscle and define FFD deformation space around these areas to adjust the unrealistic deformation. The muscle is classified into 3 types: linear muscle, sphincter and sheet muscle. The jaw of the skull is rotatable, and the existence of the skull is used for preventing the point to move to the unrealistic place. During the global deforming of the parameterized deformable facial model, we analyze the forces acting on a point and calculate the displacement of this point under a certain expression. The point on the skin mesh is under 3 types of forces: internal force of the spring, muscle force and constrained force of the skull. After computing these forces, we use the second-order ordinary differential equation (ODE) to compute the displacement of the point, and gain an expression. And then, we consider the deformation rate to see if need to use the FFD local deformation.Through the 3D facial animation system, we see a better proof. The thesis integrates many of the methods before. Our model has fewer parameters, and easily to manipulate, suite for quick modeling but not so accuracy.