title: How to detect a black lake on a white snowy background in an aerial image?
body: <p>Here is a sample aerial image:
  ![aerial image of some unfrozen lakes][1]</p>
  
  <p>How do I automatically detect and extract parameters of the black unfrozen lake from the image? I'm primarily using Python.</p>
  
  <p>EDIT: see my answer below; I think I've found the solution.</p>