A Rule-based Real-Time Face Detector

Abstract

In this paper, a real-time face detection algorithm is proposed for locating single or multiple faces in images and videos. Not only finding the face regions, this algorithm also locates the eyes and lips for each located face. The process of the proposed algorithm starts from the skin-color pixels extraction through rules built upon a quadratic polynomial model using the normalized color coordinate (NCC). Interestingly, this polynomial model with a slight modification can also be used to extract the pixels of lips very effectively. The benefit of using the same polynomial model is the reduction of computation time. Moreover, the skin-color regions and lips can be extracted simultaneously in one scan of the image or video frame. The algorithm then verifies the extracted eyes and lips using a set of rules derived from the common spatial and geometrical relationships of facial features. Finally, the precise face regions are determined accordingly. The implemented face detection system based on the proposed algorithm exhibits satisfactory performance in terms of both accuracy and speed for faces with wide variations in size, scale, orientation, color, and expressions.