A method and system for efficient non-persistent object motion detection comprises evaluating a video segment to identify at least two first pixel classes corresponding to a plurality of stationary pixels and a plurality of pixels in apparent motion, and evaluating the video segment to identify at least two second pixel classes corresponding to a background and a foreground indicative of the presence of a non-persistent object. The first pixel classes and the second pixel classes can be combined to define a final motion mask in the selected video segment indicative of the presence of a non-persistent object. An output can provide an indication that the object is in motion.