An improved technique for 3D head tracking under varying illumination conditions is proposed. The head is modeled as a texture mapped cylinder.
Tracking is formulated as an image registration problem in the cylinder's texture map image.
The resulting dynamic texture map provides a stabilized view of the face that can be used as input to many existing 2D techniques for face recognition, facial expressions analysis, lip reading, and eye tracking. To solve the registration problem in the presence of lighting variation and head motion, the residual error of registration is modeled as a linear combination of texture warping templates and orthogonal illumination templates. The regularization term tends to limit potential ambiguities that arise in the warping and illumination templates. It enables stable tracking over extended sequences. The only assumption is that the target is facing the camera in the first frame of the sequence.