text: The Facial Action Coding System is a system for the computer to read your facial expressions. In paragraph 3, the author states," The process begins when the computer constructs a 3-D computer model of the face; all 44 muscles must move human like." A movement of one or more muscle is called an "action unit". The authour also mentions that Eckman has classified six basic emotions which include happiness, surprise, anger, disgust, fear, and sadness.