[ale] OT: Video Motion Sensor

[jimpop at yahoo.com (Jim Popovitch)]

So, I'm driving around during lunchtime today and just as I am 
approaching an intersection to make a right turn (I had the quite green 
light), out of nowhere a car flies through the intersection and nearly 
hits me on the drivers side.  My attention was focused on the right-hand 
turn I was making, so I did not see the car approaching (at a high rate 
of speed) from my left.  I had just looked to the left seconds before 
and did not see any vehicle approaching my area of the intersection. 
Fortunately he missed me and thankfully he and I both made it through 
the intersection safe.

This episode got me to thinking about using cheap video cameras to 
detect large "items" approaching at considerable speed.  Obviously there 
would have to be a way to determine my speed and direction, as well as 
the speed and direction of the inbound vehicle and then some calculation 
to determine/measure a potential threat.  Does anyone know of 
software/projects/devices that do this sort of thing?

-Jim P.