How to reduce sun brightness

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skyimager
skyimager on 20 Feb 2017
Commented: Image Analyst on 20 Feb 2017
I want to reduce the effect of sun brightness from my image. I have used entropyfilt function of matlab to identify the saturated pixels and the pixels that are near saturated or high brightness pixels. I want to reduce the brightness of these high brightness pixels. These high brightness pixels are the yellow and blue marking in the image entropyfilt.jpg. The original image is the sun image.
I tried reducing the pixel values but that gives me a tint on the image and does not reduce the brightness to be specific. Please suggest how to do the same.

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Answers (1)

Image Analyst
Image Analyst on 20 Feb 2017
I suggest you use something like Photoshop's "Shadows and highlights" adjustment. I don't remember the algorithm off the top of my head, but I'm sure you can find it somewhere.
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skyimager
skyimager on 20 Feb 2017
Photoshop's "Shadows and highlights" adjustment: I did not understand. I want it to be done in matlab
Image Analyst
Image Analyst on 20 Feb 2017
I know. I saw their algorithm explained one time in a class on advanced image processing. I'll see if I can find those notes. It somehow involves identifying bright and dark regions, then using masking, applies gamma to remap gray levels, and then maybe blending to reduce contours.
Or maybe just search for HDR photography for ideas. Chances are that simple tonal adjustments, like global histogram equalization, won't perform very well.

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