Facial Expression Recognition System :Basics

As an important part of technology for humanmachine interface, FER draws much attention recently and numerous methods are proposed .For human beings ,facial expressions is one of the most powerful, natural and non verbal way to communicate their emotions and intensions. A human being can detect facial expression without efforts, but for a machine it is very difficult. This paper describes the problem of facial expression recognition in the field of computer vision .Firstly, the psychological background of a problem presented. Then the idea of facial expression recognition system (FERS) is outlined and the requirement of such system is specified. The FER consists of 3 stages: face detection, feature extraction and expression recognition .Method proposed in literature are reviewed for each stage of system.