Before we can do face recognition, the portion of the image that contains the face must be first detected. Here is a demo on face detection using template matching. A frontal face template was used to detect the presence of a face in each frame of the video. We see that although the algorithm did not manage to detect the face when the subject turned his face side-way or tilted his head by a significant amount, as soon as the camera captured the frontal view of his face, the rectangle immediately locked onto his face again.