Building Computer Vision Projects with OpenCV 4 and C++

Separate histogram equalization for left and right sides

In real-world conditions, it is common to have strong lighting on one half of the face and weak lighting on the other. This has an enormous effect on the face recognition algorithm, as the left- and right-hand sides of the same face will seem like very different people. So, we will perform histogram equalization separately on the left and right halves of the face, to have a standardized brightness and contrast on each side of the face.

If we simply applied histogram equalization on the left half and then again on the right half, we would see a very distinct edge in the middle because the average brightness is likely to be different on the left and the right side. So to remove this edge, ...