Facial action recognition in face profile image sequences
A robust way to discern facial gestures in images of faces, insensitive to scale, pose, and occlusion, is still the key research challenge in the automatic facial-expression analysis domain. A practical method recognized as the most promising one for addressing this problem is through a facial-gesture analysis of multiple views of the face. Yet, current systems for automatic facial-gesture analysis utilize mainly portrait or nearly frontal views of faces. To advance the existing technological framework upon which research on automatic facial-gesture analysis from multiple facial views can be based, we developed an automatic system as to analyze subtle changes in facial expressions based on profile-contour reference points in a profile-view video. A probabilistic classification method based on statistical modeling of the color and motion properties of the profile in the scene is proposed for tracking the profile face. From the segmented profile face, we extract the profile contour and from it, we extract 10 profile-contour reference points. Based on these, 20 individual facial muscle actions occurring alone or in a combination are recognized by a rule-based method. A recognition rate of 85% is achieved.