Illumination Invariant Face Recognition: A Survey

Illumination variation is one of the well-known problems in face recognition, especially in uncontrolled environments. This chapter presents an extensive and up-to-date survey of the existing techniques to address this problem. This survey covers the conventional passive techniques that attempt to solve the illumination problem by studying the visible light images, in which face appearance has been altered by varying illumination, as well as the active techniques that aim to obtain images of face modalities invariant to environmental illumination.