Abstract: Apparatus and method for processing a sequence of images of a scene, the method including: tracking a region of interest in the sequence of images (e.g. using a Self Adaptive Discriminant filter), selecting a particular image in the sequence, selecting a set of images from the sequence, the set of images including one or more images that precede the particular image in the sequence of images; and determining a value indicative of the level of change between the region of interest in the particular image and the regions of interest in the images in the set of images (e.g. using a Change Detection Process).