Determination of pivot point of a human head from the front

Finding the pivot point of a human head, also known as the top of spine in the MPEG-4 standard, is a vital step in many applications, such as head pose determination, face modeling, 3D animation, etc. Biologically, there is no such point as the pivot point of the human head, because movements like turning or tilting the head involves all the bones on the neck. For the convenience of modeling the movements of human head, it is beneficial to assume that the head moves based on a pivot point. This paper estimates the location of this pivot point by using two images. One image is the front view of the person of interest, and other view is a movement after a combined rotation of pitch and row angle in arbitrary magnitude. Two or more feature points from both images are matched and a numerical approach is used to calculate the pivot points. The result is satisfactory.