For the speed of detecting human faces in single grayscale scene imgae is slowly

an approach of knowledge based fast face detection is proposed. In the method a tri part mosaic image model is supplied

which is consistent with physical structure features of human face. Basing on this model

knowledge base

including information of edge and gray in images

is established by analyzing fairly enough human face images. Moreover

in order to enhance the speed of detecting face

hierarchical detection processes is adopted. In the process of rough face detection

a new coarse detection method--extended projection which is according with the physical structure features of eyes is presented and applied

which makes it possible to get different scale face candidate region

thus reduces the computation time of face detection greatly. Our experimental results indicate that the approach is high robust

and it is fit to solve the problem of multi face detection in complex background. Because of the algorithm's simpleness

it can be easily achieved by hardware

and this will shorten the time consuming on face detection. This made it possible to detect faces in real time. So it has wide application perspective at fields of visual telephone

intelligent monitor etc.