I. Introduction
Face recognition plays an increasingly important role in today’s society [1]. Traditional face recognition methods are suitable for face images in experimental environment.However, in the natural environment,it is tough to maintain the front face all along.After the deflection of the facial posture,the facial organs are often displaced,and the self-shielding effect will also occur,which will lead to the loss of most features of the face. When the rotation angle of the face reaches 45° to 90°,the displacement of the facial organs becomes more significant and the accuracy of recognition is greatly reduced.