Real-time Face-based Auto-Focus for Digital Still and Cell-Phone Cameras

Auto-focus (AF) is a common feature in consumer level digital and cell-phone cameras. Face-based AF, or AF based on face detection, has become of interest due to the fact that the majority of pictures captured by consumers are of human faces. While many face detection algorithms exist in the literature, very few of them are actually suitable for real-time deployment on resource limited digital or cell-phone camera processors. In this paper, a face-detection algorithm combining a Gaussian skin color model with a computationally efficient sub-block postprocessing scheme is introduced to address the realtime constraints encountered in digital and cellphone cameras. This approach has been implemented in conjunction with our previously developed rule- based AF method in order to achieve real-time faced- based AF on the Texas Instruments programmable TMS320DM350 digital camera processor.