Hi, I have images from a lc display and I want to find lint or dust or similar defects.
The problem is the quality of the images. I have some kind of gradient in the brightness. Some parts are darker, other parts are brighter and the overall brightness varies from picture to picture. There is also a pattern from the pixel segments.
first, there seems to be a red pixel stuck near the center of the picture, in all pictures. I’m guessing you need that ignored. that should be fixable by picking that pixel once, and then erasing it with an average of the surrounding ones.
I see some “saturation” effect near the backlight. green saturates already and then red does too. saturation is somewhat undesirable. perhaps tweak the camera parameters so those areas are still in range.
the grids you might be able to attenuate with a fourier transform and careful erasing (nulling) of coefficients that correspond to the grid. or just ignore. or blur (median blur maybe) but that could attenuate the lint as well.
I don’t have any code. I just play around with Gimp to understand how the filters work.
Sadly the pixels are OFF. The contrast setting is much too high. I know that, but that’s the settings our “experts” are using.
I hope that I can change that in the near future. I see there is room for improvement, but I have to learn more about image processing. That’s why I try to get the best out of the current images.
Btw: I have some good results using a combination ob Sobel X and Y (in Gimp G’mic). This removes the grid and the gradient. But there are still too many artefacts especially at the bottom side. I will upload some examples later.
