title: How can I change the contrast of an image using OpenCV?
body: <p>I'd like to look at the contrast of an image in a certain masked region, and reduce it if it is too great.  Are there built-in functions that can help me with this?  If not, what sort of algorithm should I be looking at?  I assume I would be looking at/changing the value of pixels to bring them closer to the average, and perhaps average distance from the average is a good measure of initial contrast?</p>
  
  <p>I am using EmguCV if that is relevant.</p>