1. A computer-implemented method for classifying a detected region of change of a video frame as one of an abandoned object and a removed object, wherein a plurality of boundary blocks define a boundary of said detected region of change, said method comprising the steps of: (1) for each one of the plurality of said boundary blocks: (a) determining a first difference between a predicted edge orientation and an observed edge orientation of said boundary block; (b) determining a second difference between a historical edge orientation of said boundary block and at least one of the predicted edge orientation and the observed edge orientation of said boundary block; and (c) determining a temporal change of edge consistency based on the first and second difference; and (2) classifying said detected region of change as one of the abandoned object and the removed object based on the determined temporal change of edge consistency of the plurality of boundary blocks.