I have come across this greyscale image which has like an overlay on it. This overlay is like looking through a bathroom window (through the kind of glass you cannot see clearly, yet it lets light through). This overlay is not enough to destroy the picture at normal magnification, yet at high magnification examining the image in detail, you can see it is there and it stops the fine detail from being inspected.
What I am wondering is if it is possible to remove the 'overlay'? Maybe if I can isolate a piece of the overlay, can I use it as a mask to remove the rest of it? Can I do a simple subtraction on the original image?
I suspect not, which might be the reason this overlay was introduced in the first place, although it is not a restricted image.
I have tried blurring and then sharpening again but the the result is fine detail is merged into the overlay.
Does anyone have any ideas please?