1. A method to identify a moving object in a video, comprising: generating a background frame based on a first frame in the video; generating a foreground frame based on a second frame in the video, wherein the second frame follows the first frame in the video; comparing the foreground frame with the background frame at each corresponding location; acquiring an object area including corresponding locations each having a difference greater than a threshold; determining, using a processor, whether the object area contains a moving object based on one or more of a size and a shape of the object area; when the object area contains a moving object, identifying, using the processor, the moving object; updating, using the processor, the background frame according to the difference between the background and the foreground frames at each corresponding location, wherein updating the background frame comprises, at each corresponding location, responsive to determination that the difference between the background and the foreground frames at the corresponding location exceeds the threshold, adding a predetermined factor to a pixel value of the background image; generating an other foreground frame based on a third frame in the video, wherein the third frame follows the second frame in the video; and repeating comparing, acquiring, and determining from the updated background frame and the other foreground frame.