A colleague mentioned a course in digital signal processing where he remembered the expression "normalizing the curve" or "normalizing the image" to make it as accurate as possible and get better image resolution and small details. He drew a histogram of a picture with three sharp peaks and another histogram after normalization with the peaks in the same locations but with larger spread.
The colleague could remember nothing more. I could not find a reference for those expressions. It sounds to me like gamma correction with RGB photos or High Dynamic Range in RAW photos.
Is that right, or is that a different technique?
Update: The colleague was processing photos in Matlab, in case that's relevant.