title: OpenCV image blending
body: <p>I doing faceswap app using OpenCV and let's say I've found 2 faces in the picture and then I've cropped the face rectangles with ellipse. My problem is that both of these faces have different skin color so if I just simply swap the coordinates of the ovals, the result doesn't look so good. So I was thinking at least about adjusting the color of the face according to the original face. </p>
  
  <p>I believe it is possible to achieve with OpenCV library but I just don't know the name of the method I should look for. Also it is important that the method is fast enough because I am developing this application for Android.</p>