title: Opencv: zero pixels outside of region of interest with rotated rectangle?
body: <p>I have a rotated rectangle representing my region of interest:</p>
  
  <pre><code>[[634 547]
  [353 504]
  [436 -41]
  [717   1]]
  </code></pre>
  
  <p>I'd like to quickly filter out all pixels not inside of that rotated rectangle. Note that the rectangle actually is beyond the bounds of the image, so I have to deal with that edge case if it matters.</p>