Optimizing Quantization Noise

Hi,

I am using image acquisition toolbox for comparing two frames captures by external webcam. I am shooting at 160x120 and grayscale but even with these lowest setting, there seems to be difference in two identical frames. I am testing the quantization noise level capturing 2 full black (no light entering the lens) frames and comparing them but there seems to be some difference in these two identical frames.

I would appreciate if anyone could come up with a solution that will optimize/lower the quantization noise. All valid configurations (resolution, camera settings, brightness-contrast-exposure etc) are acceptable.

[Walter Roberson]

See also the comments I just added to your earlier question, http://www.mathworks.com/matlabcentral/answers/8359-comparing-two-frames