Technique: remove background by combining two images? I have two videos - both are on a tripod, so they are locked in place. First video has an empty background (no people or objects), the second video has a person walking through the scene.

Is there a technique that allows me to combine the two images - have the empty background remove the background from the person walking through it - and only keep the person with a transparent background?
I believe the effect you're after is Difference Matte. Keep in mind your clean plate needs to be exactly the same, pixel for pixel, as in your shots. You'll likely need to do some manual clean up as well.