Zonedetector is a motion detection directshow filter that can encircle moving objects in video from static cameras survelance ones, for example. It can also send messages to the main program on the motion level. Very useful for biulding your own surveillance system. The project is GPL-ed. It also includes a simple example program, demonstrating its power. It is not yet well documented, though.

full source codes

binary files only

presentation

You will also need these dlls