Facial Expression Recognition Using Image Motion

Introduction The communicative power of the face makes machine understanding and recognition of human expression an important problem in computer vision. There is a significant amount of research on facial expressions in computer vision and computer graphics [11, 23]. Perhaps the most fundamental problem in this area is how to categorize active and spontaneous facial expressions to extract information about the underlying emotional states [6, 26]. Ekman and Friesen [10] have produced the most widely used system for describing visually distinguishable facial movements. This system, called the Facial Action Coding System or FACS, is based on the enumeration of all "action units" of a face which cause facial movements. As some muscles give rise to more than one action unit, the correspondence between action units and muscle units is approximate. However, it is widely recognized that the lack of temporal and detailed spatial information (both loca