title: Detect the size of a QR Code in Python using OpenCV and Zbar
body: <p>I have code that takes an image from the webcam, scans it for QR codes using zBar and returns the value of the code and an image with the QR code highlighted (based off <a href="http://sourceforge.net/p/qrtracker/wiki/Home/" rel="nofollow">http://sourceforge.net/p/qrtracker/wiki/Home/</a>). How can I also make it tell me the size of the code (as a pixel value or % of the screen)?</p>
  
  <p>Additional question: is there a way to detect how skewed it is (e.g rotation in Z about the Y-axis)?</p>