Motion Parameters Estimation in Facial Sequence
人脸序列图象的头部运动参数估计

Model based facial image coding has received extensive attention due to its high subjective image quality and low bit rates. But the estimation of object motion parameters is still a difficult problem. In this paper, head motion characteristics is analyzed, and it can be classified into three motion types, head rigid motion, simple motion of facial expression and complex motion of facial expression. A motion parameter estimation algorithm based on corresponding feature points is utilized to extract head rigid motion. A linear implementation algorithm is suggested. The key works to improve the accuracy of motion parameter estimation are the selecting of some proper feature points and the building of an exactly 3D wire frame corresponding to specified face. A deformable matrix is constructed to extract simple motion parameter of facial expression. At last, the error of motion parameter is evaluated by the area error function.