There are various ways in which local exposure distortions can be introduced to an image.
One of the ways would be:
- Create a binary mask of the same size as the original image.
- Randomly choose size and location of patches (rectangular are the easiest, would just need to select the indexes in a matrix)
- Assign some value (say 75 for over exposed) and add the binary mask to the original image.
- This can be done in a loop and the randomness would help in creating different distortions for each image if need be.
In terms of code, taking an example, it would look like:
I=(imread('coins.png'))
Imask = zeros(size(I));
Imask = uint8(zeros(size(I)));
Imask(20:40,60:90)=75;
imshow(I+Imask)
This is just an illustrative example and should serve as a starting point.
