title: How to find rectangle in black region opencv (C++)
body: <p>I'm newbie OpenCV. I am using opencv for find position attach a stamp in image. The stamp can't overlap with other object in image.</p>
  
  <p>Example binary image with white region is object on image, black region is none object
  <a href="https://i.stack.imgur.com/NQdmi.png" rel="nofollow noreferrer">Example image</a></p>
  
  <p>Result : Find rect in black region (in white circle) can attach stamp
  <a href="https://i.stack.imgur.com/otX76.png" rel="nofollow noreferrer">Result imagge</a></p>
  
  <p>Please help me find rect in black region same blue rect.
  Thank you!</p>