Blender Background Subtraction: Pulling a nice matte.


Can anyone help me on this one? I have two source files, one is a video and one is a picture of the exact same scene, minus the subject. Like the pics below:


Is it possible to take the image of the background and subtract it from the video to be left with either a final image or a matte that can be used to alpha map the background out? I have tried the difference and subtraction methods, and they won’t produce what I can see to be a usable matte. Maybe I am doing something wrong. Hope someone can help. I have attached my results with the difference and subtraction methods, and the node setup I am using (just to get the matte, I don’t have the nodes set up to add in a new background yet)



I have given it a try too
with basically the same setup.

but it seems that in some areas you and your background seem to be surprisingly “equal”.
so there´s no real answer from me. sorry.

An interesting idea. I guess if it would work, though, people wouldn’t still be spending money on green screens.