title: opencv: Correcting these distorted images
body: <p>What will be the procedure to correct the following distorted images ? It looks like the images are bulging out from center.    These are of the same QR code, and so a combination of such images can be used to arrive at a single correct and straight image. 
  Please advice.     </p>
  
  <p><img src="https://i.stack.imgur.com/grNeL.jpg" alt="enter image description here">
  <img src="https://i.stack.imgur.com/G0oYe.jpg" alt="enter image description here">
  <img src="https://i.stack.imgur.com/sWN0f.jpg" alt="enter image description here"></p>