LAFTER: a real-time face and lips tracker with facial expression recognition

This paper describes an active-camera real-time system for tracking, shape description, and classification of the human face and mouth expressions usi ng only a PC or equivalent computer. The system is based on use of 2-D blob features, which are spatially compact clusters of pixels that are similar in terms of low-level image properties. Patterns of behavior (e.g., facial expressions and head movements) can be classified in real-time using hidden Markov models (HMMs). The system has been tested on hundreds of users and has demonstrated extremely reliable and accurate performance. Typical facia l expression classification accuracies are near 100%. (C) 2000 Pattern Reco gnition Society. Published by Elsevier Science Ltd. All rights reserved.