Automatic recognition and analysis of human faces and facial expressions: a survey

Humans detect and identify faces in a scene with little or no effort. However, building an automated system that accomplishes this task is very difficult. There are several related subproblems: detection of a pattern as a face, identification of the face, analysis of facial expressions, and classification based on physical features of the face. A system that performs these operations will find many applications, e.g. criminal identification, authentication in secure systems, etc. Most of the work to date has been in identification. This paper surveys the past work in solving these problems. The capability of the human visual system with respect to these problems is also discussed. It is meant to serve as a guide for an automated system. Some new approaches to these problems are also briefly discussed.