Linear method for performing head motion estimation from facial feature data,
the method comprising the steps of: obtaining first facial image and detecting
a head in the first image; detecting position of four points P of said first facial
image where P={p1, p2, p3, p4}, and
pk=(xk, yk); obtaining second facial image and
detecting a head in the second image; detecting position of four points P
of the second facial image where P={p1, p2,
p3, p4} and pk=(xk,
yk); and, determining the motion of the head represented by
a rotation matrix R and translation vector T using the points P and P.
The head motion estimation is governed according to an equation:
Pi=RPi+T,
where
##EQU1##
and T=[T1 T2 T3]T represents camera
rotation and translation respectively.