1. A face feature analysis method for distinguishing features of a face of a subject in variable lighting conditions, comprising the steps of: a) generating a plurality of eye, nose and mouth candidates within a current image frame which includes the face of the subject; b) defining a nostril tracking window within the current image frame around one of the nose candidates, wherein said nostril tracking window is defined so as to exclude the eye and mouth candidates and to assure inclusion of nose nostrils of the subject in a next frame after a fastest possible head movement between said current and next frames; and c) analyzing each pixel within said nostril tracking window to determine whether the nose candidate enclosed within said nostril tracking window represents actual nostrils by performing a skin color area test and a nostril area test.