  We describe a method for estimating human head pose in a color image that
contains enough of information to locate the head silhouette and detect
non-trivial color edges of individual facial features. The method works by
spotting the human head on an arbitrary background, extracting the head
outline, and locating facial features necessary to describe the head
orientation in the 3D space. It is robust enough to work with both color and
gray-level images featuring quasi-frontal views of a human head under variable
lighting conditions.
