Automatic recognition of facial expressions in image sequences: A review

For human beings, facial expression is one of the most powerful and natural way to communicate their emotions and intensions. A human being can detect facial expressions without effort, but for a machine it is very difficult. Automatic facial expression recognition is an interesting and challenging problem. Automatic facial expression recognition systems can be mainly used for human computer interaction and data driven animation. There are three sub problems while designing automatic facial expression recognition system, face detection, extraction of the facial expression information, and classification of the expression. A system that performs these operations more accurately and in real time would be crucial to achieve a human-like interaction between man and machine. This paper reviews the past work done in solving these problems for image sequences.