The most commonly used vision-based coding system is the Facial Action Coding System (FACS ) proposed by Ekman and Friesen [5] for The Facial Action Coding System. : A technique for measuring facial movements, FACS enables the analysis of facial expressions through standardized coding of changes in facial movements in terms of atomic facial actions called action units (AUs). Facial activity tracking and recognition are characterized by three levels. First, at the lower level, facial feature points around each facial component are captured. At the second intermediate level, facial action units defined using the Facial Action Coding System (FACS) represent the contribution of a specific set of facial muscles. Finally, at the top level, six prototypical facial expressions represent the overall movement of facial muscles and are commonly used to describe human emotional states. Lyons et al. [6] Facial attribute classification using 2D Gabor wavelet representation and discriminant analysis used a set of multi-scale, multi-orientation Gabor filters to first transform the images . Gabor's coef...