Emotion recognition based on MPEG-4 Facial Animation Parameters

In this paper a facial expression recognition system is presented. The system is based on the modelling of the expressions by means of Hidden Markov Models. The observations used to create the models are the MPEG-4 standardized Facial Animation Parameters (FAPs). The FAPs of a video sequence are first extracted and then analyzed using semi-continuous HMM. The system shows good performance for distinguishing isolated expressions and can also be used, with lower accuracy, to extract the expressions in long video sequences where speech is mixed with silence frames.