1. A method for classifying a visual element as either foreground or background in a video frame, the method comprising the steps of: computing a blob boundary characteristic for a blob obtained from the video frame which is captured by a camera module including a processor and a memory storing a computer executable software program for directing the processor to compute the blob boundary characteristic, wherein said blob comprises at least one visual element corresponding to a scene model which comprises a plurality of modes, and said visual element is labelled foreground based on at least a match mode boundary characteristic in the scene model; and updating the scene model based on at least the computed blob boundary characteristic and the match mode boundary characteristic.