title: Detecting if a bottle has a label
body: <p><img src="https://i.stack.imgur.com/dgDVJ.png" alt="enter image description here"><img src="https://i.stack.imgur.com/tM6Ch.png" alt="enter image description here"><img src="https://i.stack.imgur.com/CAsN3.png" alt="enter image description here">I am currently doing a bit of computer vision using openCv. I have a sample of bottles a label on it. I am trying to determine when a bottle does not have a label on it.
  The label is rectangular in shape.</p>
  
  <p>I have done an edge detection using Canny.I have tried  using findcountour() to detect if a bottle has an inner contour(this would represent the rectangular label).</p>