I spend a lot of time thinking about randomness, and after running some tests on the entropy of dark images, I have started to believe that there is a lot less entropy in dark CCD images than people think, but there is still enough to get a useful entropy stream.
A substantial portion of the "noise" from a CCD is definitely not random.
I'm curious, how close to raw CCD data did you get from consumer cameras? It wouldn't surprise me if hard-wired camera internal postprocessing often almost immediately regularizes random noise, even with raw images and software postprocessing turned off. Just a wild-ass guess though.
If I were going to take a stab at this, I would guess that most of the "camera" is really unnecessary and that you could do this using just the image sensor.
A lot of the camera is just functionality to make actual pictures better that don't apply here. Eg you don't need to control exposure with shutter speed if it's in a black box.
Having a whole camera might even be counterproductive. Eg actuating the shutter is predictable, so it might reduce entropy if actuating the shutter creates a signal that shows up in the randomness.
Or maybe they just mean pro quality cameras, but I'm not sure why you'd want a whole camera instead of just the sensor. Reasons are not readily apparent, and I don't expect anyone to be immediately ready to correct me on trade secrets.
A substantial portion of the "noise" from a CCD is definitely not random.