Table 1.

Action Units used for monitoring the ability in producing the foru basic facial expressions (H = Happiness; S = Sadness; F = Fear; and A = Anger).

AU	Full Name	Example	Involved in
AU1	Inner brow raiser		S-F
AU2	Outer brow raiser		F
AU4	Brow lowerer		S-F-A
AU5	Upper lid raiser		F-A
AU6	Cheek raiser		H
AU7	Lid tightener		A
AU9	Nose wrinkler		A
AU12	Lip corner puller		H
AU15	Lip corner depressor		S
AU17	Chin raiser		A
AU20	Lip stretched		F
AU23	Lip tightener		A
AU25	Lips part		A
AU26	Jaw drop		F