Liveness Measurements Using Optical Flow for Biometric Person Authentication

Biometric identification systems, i.e. the systems that are able to recognize humans by analyzing their physiological or behavioral characteristics, have gained a lot of interest in recent years. They can be used to raise the security level in certain institutions or can be treated as a convenient replacement for PINs and passwords for regular users. Automatic face recognition is one of the most popular biometric technologies, widely used even by many low-end consumer devices such as netbooks. However, even the most accurate face identification algorithm would be useless if it could be cheated by presenti ng a photograph of a person instead of the real face. Therefore, the proper liveness measurement is extremely impor tant. In this paper we present a method that differentiates between video sequences showing real persons a nd their photographs. First we calculate the optical flow of the face region using the Farneback algorithm. Then w e convert the motion information into images and perform the initial data selection. Finally, we apply the Sup port Vector Machine to distinguish between real faces and photographs. The experimental results confirm that the proposed approach c ould be successfully applied in practice.