title: Find angle between normal and perspective images
body: <p>I have 2 photos of chessboard from camera. I need to find angle between planes on 2 images. For example we have normal "chessboard" image, after some transformations we got a new image in perspective "chessboard2". Is it possible to find angle between those planes?</p>
  
  <p>Normal chessboard:
  <a href="https://i.stack.imgur.com/Odm5f.png" rel="nofollow noreferrer">Normal</a></p>
  
  <p>Perspective chessboard:
  <a href="https://i.stack.imgur.com/fhWSe.png" rel="nofollow noreferrer">Perspective</a></p>
  
  <p>For understanding: i try to find angle φ between planes.<a href="https://i.stack.imgur.com/mReiJ.jpg" rel="nofollow noreferrer">image φ</a></p>
  
  <p>I've tried to solve this by python(opencv) program. I used cv2.getPerspectiveTransform() function to find transformation matrix, but i can't pull out the angles I need :(</p>
  
  <p>Thank you!</p>