Michele Covell and Chris Bregler, "Eigen-points," Proceedings of 3rd IEEE International Conference on Image Processing. Lausanne, Switzerland, September 16-19, 1996. pp. 471-4 vol. 3.

Eigen-points places control points onto unmarked images. The control points are the image locations corresponding to fiduciary points on an object. For example, we might designate ten points on the outside boundary of the lip as fiduciary points on a face. Then, the control points mark the image locations where those points on the outside lip boundary appear. The control-point locations are estimated using a coupled manifold model, which describes the joint variation of the image appearance and the control- point location.