Detect Motion in Camera-Images

[Marco Tedaldi]

Hello G-Community :-))

I've had the chance to gain some expirience with programming in LabView. 
But now I have to solve a Problem in a field that's completeley new for 
me (i really love this job, something new everytime).

I have a Camaera from which I grab an Image every second (with 
single-image acquisition I could got up to 10 per Second, but that's not 
necessairy). I'm savint every 60th Image. The Camera points to a cage 
where rats are livin in. Now I want to save the Images at a higher rate, 
when movement is detected in the Image.

At the moment I'm just substracting the last image from the actual one 
(funny to look at the resultign pics). I'm looking at the mean value of 
the result of the substraction, which seems to be a good indicator of 
changes. The Problem is now, that the mean also rises, when the ambient 
light changes. To lower this effect I thought about just substracting 
the linear value from the (quadratic) mean. Would this be a way?

Are there functions exactly for this in IMAQ eventually? (I have LabView 
6i and IMAQ 6.0).

Thank you and bye

Marco