A term to describe the different facial muscles involved in an expression. The facial action coding
system (FACS) of Ekman and Friesen (1978) gives detailed descriptions of all the changes in appearance that accompany each of 44 action units they identified in the face. Attempts have been made to automatically track facial action units by means of motion analysis systems.
system (FACS) of Ekman and Friesen (1978) gives detailed descriptions of all the changes in appearance that accompany each of 44 action units they identified in the face. Attempts have been made to automatically track facial action units by means of motion analysis systems.
See Behavior system, Communication, Display rules, Facial expressions