title: How to select the largest contour in MATLAB
body: <p><img src="https://i.stack.imgur.com/a5Yi7.jpg" alt="enter image description here"></p>
  
  <p>In my progress work, I have to detect a parasite. I have found the parasite using HSV and later made it into a grey image. Now I have done edge detection too. I need some code which tells MATLAB to find the largest contour (parasite) and make the rest of the area as black pixels. </p>