title: Blur Image using a Binary Mask - OpenCV Python
body: <p>I have an RGB image and a binary mask of same dimensions. I want to blur only those portions of the RGB image where the value of mask is <code>255</code> (white). How to do this in OpenCV Python?  </p>
  
  <p>I tried implementing the method given in the answer of morotspaj in <a href="https://stackoverflow.com/questions/20818179/smoothing-mat-of-float-with-mask">Smoothing Mat of float with mask</a> but didn't quite get the result I was expecting. Can someone explain it?  </p>