title: Binary Image, Concentrations of White Dots with OpenCV
body: <p>Given a binary image of black, with a few sporadic white dots, I'm looking for a way to "lasso" a majority of the white dots inside a bounding rectangle. Consider this image:</p>
  
  <p><img src="https://i.stack.imgur.com/yeJ3U.png" alt="enter image description here"></p>
  
  <p>See how not <strong>all</strong> of the dots are enclosed, but just the clusters (or set of clusters) where there are clearly more white dots than anywhere else?</p>
  
  <p>I already know how to <a href="http://felix.abecassis.me/2011/10/opencv-bounding-box-skew-angle/" rel="nofollow noreferrer">put a bounding box around all of the white dots</a> with OpenCV. Can anyone direct me as to how I can analyze this image for <strong>one big concentration of dots</strong>, ignoring any peripheral dots which are not really part of a group?</p>
  
  <p><strong>N.B.:</strong> This bounding box doesn't have to be skew. Even a convex hull would be nice as output.</p>
  
  <p>I can adjust the size, color, alpha, location, density, etc. of these dots. So if your thoughts involve doing something with these dots in order to process them, that might work.</p>