1. A non-transitory computer-readable medium comprising software for video processing, which when executed by a computer system, cause the computer system to perform operations comprising a method of: receiving video from an overhead view of a scene; detecting moving pixels in the video; detecting line segments in a foreground of the scene in the video based on detected moving pixels; identifying targets in the video based on the detected line segments; tracking targets in the video based on the identified targets; and managing tracked targets in the video, wherein detecting line segments comprises: counting edge pixels; and identifying a line segment based on the edge pixels.