Appscio is looking for an algorithm to showcase in a government project we're about to undertake.  In the course of researching possible sources, we recently ran across an Australian firm called Sentient Vision Systems.  The company appears to have a variety of algorithms designed to detect moving objects and unusual activity in fixed and moving camera systems. 

We've contacted them and will post again when we have more to report.  But, some of their demonstration videos show an impressive ability to identify moving objects as small as a few pixels high in video shot from a moving platform.