Spoofed Facial Presentation Attack Detection by Multivariate Gradient Descriptor in Micro-Expression Region

Facial video presentation is a topic of interest in many security systems due to its non-intrusive nature. However, such systems are vulnerable to spoof attacks made by fake face videos and thereby gaining unauthorized access in the system. For a robust biometric system anti spoofing approaches like liveness detection ought to be implemented in order to counter the aforesaid print and replay attacks. This article proposes a novel approach of anti spoofing using Multivariate histogram of oriented gradients descriptor in the auto detected micro expression (μE) regions of human facial videos. Facial μE are very brief, spontaneous facial expressions that highlight the face of humans when they either unconsciously or deliberately conceal an emotion. The work emphasizes the variations in μE in fake and original video representation by a considerable amount and claims such a variance is a tool to combat against presentation attacks. In particular, the method automatically extracts the ROI of major changes in μE using the Multivariate orientation gradients parameter and thus proposes this descriptor as one of the most suitable tools to characterize the liveness. The entire implementation is carried out on the self-created Database for replay attacks. The result obtained is satisfactory and tested statistically significant.