ABSTRACT
Face recognition is considered as an effective biometric identi-
fication technique that is used in a wide range of applications
such as video surveillance and law enforcement. In real-world
scenarios, dramatic degradation occurs by illumination variation,
facial expression, occlusion, head pose, aging effect, blur, and low
resolution. In this chapter, the effect of illumination and occlusion, as
two challenging appearance changes in unconstrained environment,
on the face recognition algorithms is evaluated.
