1. A method of tracking an object appearing in a video sequence comprising a plurality of frames, each frame comprising a plurality of pixels, the method comprising: (i) comparing first and second frames of the video sequence to identify a region of pixels therein representing an object having inter-frame motion; (ii) determining whether said region appears in a predetermined number of subsequent frames, and, if so, assigning a motion parameter to said region indicative of the change in position thereof over said predetermined number of frames; (iii) comparing said motion parameter with a threshold value to determine whether or not said region is to be tracked; and (iv) if the region is to be tracked, recording the frame position of said region for subsequent frames in which said region is identified.