1. A method for tracking an object in an image sequence, wherein a track in the image sequence is associated with a track signature, the track signature comprising at least one mode, said method comprising the steps of: detecting the object in a current frame of the image sequence; associating the detected object with a representative signature; determining a spatial difference indicating a difference in size or position between the track and the detected object; determining a visual difference between the at least one mode of the track signature and the representative signature; combining the spatial difference and the visual difference into a combined difference; and associating the detected object with the track if the combined difference is less than a combined difference threshold.