Face anti-spoofing methods.

In recent years, facial biometric systems have received increased deployment in various applications such as surveillance, access control and forensic investigations. However, one of the limitations of face recognition system is the high possibility of the system being deceived or spoofed by non-real faces such as photograph, video clips or dummy faces. In order to identify the spoofing attacks on such biometric systems, face liveness detection approaches have been developed. Thus, the current approach is to integrate liveness detection within facial biometrics by using life sign indicators of individual features. This article presents a review of state-of-the-art techniques in face liveness detection, which are classified into two groups, namely intrusive and non-intrusive approaches. Here, each technique is discussed in terms of its implementation, strengths and limitations, as well as indications on possible future research directions that can be studied. [ABSTRACT FROM AUTHOR]