1. A method of classifying visual elements in a region of a video as either foreground or background, the method comprising: classifying each visual element in the region as either foreground or background using a first classifying method; expanding spatially at least one of the visual elements classified as foreground to form a spatially expanded area; and classifying the visual elements in the spatially expanded area as either foreground or background using a second classifying method that is more sensitive for detecting foreground than the first classifying method.