Which image comparison method should I use?

Hi All,

I have the same images (the same pattern) those are taken from different TV panels via LVDS. (This is not an identical process, let's say we have 2 images.)

The patterns (color bar) are the same.But it fails when I compare them.

How can I compare them?

Which filters or methodology should be used.

Could you please inform meon these subjects.

Thanks in advance.