Method Of Detecting Face Direction Using Image Processing For Human Interface
Kazunori Ohmura, Akira Tomono, Yukio Kobayashi · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1988
A method of non-contact detection of human face direction using a TV image and its application to pointing operation are presented. First, an algorithm for detecting the direction of a human face is described. In this method, the human face is defined as a plane having three feature points. Here, 2-D coordinates of these points projected on a TV image, together with the distances between points measured on the face are used to obtain the 3-D positions of the feature points. The normal vector of the plane, same as face direction, can be calculated from those values of the 3-D positions. Next, the accuracy of this algorithm is evaluated by experiment. Three blue marks are pasted on the human face as the feature points. These marks are extracted from the TV image by the chroma key method and the face direction is calculated by the above algorithm. This result is compared with the direction obtained from a high accuracy 3-D magnetic sensor attached to the subject's head. For real time detection, a fast method of finding the marks on a TV image is described. A window is set around each mark and the search process is applied within this window. The position of the window follows the marks' movement. Finally, to determine if the processing speed is in real time, a pointing operation that uses face direction detected by this method is tested with a menu selection task. Results of these experiments show that 3-D face direction can he detected in real time, and that this method is effective in human-interfaces such as menu selection.