title: OpenCV::matchShapes() example?
body: <p>I would like to use <code>matchShapes()</code> function to find an object inside a query image.</p>
  
  <p>Let's say I have a model image of a book, i want to extract its shape and then try to find this book (its shape) inside another image.</p>
  
  <p>I have googled a lot but couldn't find any real example on how to use <code>matchShapes</code> to achive this. The documentation lacks. Can someoen make a little example in C++ ?</p>
  
  <p>Thanks a lot! (Note I know I can use SIFT/ORB etc, but i want to use matchShapes())</p>