1. A method for detecting a face in a video stream comprising: receiving, at a video processing apparatus, a sequence of input color images; and for each input image, processing the sequence at the video processing apparatus, wherein the process includes, calculating a greyscale image of the input color image, creating a one-bit motion image based on the current greyscale image and a previous greyscale image, calculating a normalized color image of the input color image, calculating a motion color probability image by, calculating a first color histogram of the pixels in the normalized image, calculating a second color histogram of the pixels in the normalized image corresponding to pixels in the motion image defined as being in motion, calculating a ratio histogram by dividing the first color histogram by the second color histogram, and setting pixel values in the motion color probability image to a value obtained by indexing the ratio histogram using values from the original normalized image, providing at least the grayscale image and the motion color probability image to a face detector, and executing face detection by determining a presence of a face based on first features in the grayscale image and second features in the motion color probability image.