1. Video face detection apparatus in which a test image from a video sequence is compared with an image property model derived from image properties of a region detected to contain a face in a preceding image in said video sequence; said apparatus comprising: (i) a selector to select a predetermined proportion of pixels in said region detected to contain a face in said preceding image which most closely match said image property model derived in respect of that region, thereby deriving a pixel mask; (ii) a comparator to compare pixels in said test image defined by said pixel mask with said image property model, said mask being applied at more than one image position within said test image; a face being detected in said test image at a mask position corresponding to a lowest average difference between said image property model and pixels defined by said mask at that position.