title: How to detect area of pixels with the same color using OpenCV
body: <p>Using OpenCV Python, I'm wondering what would be the best method to identify areas of an image that have a high concentration of pixels of a certain color, and maybe to 'mark' them by plotting a circle around them.</p>
  <p>I tried working with <code>findContours</code> method, but it's a mess...</p>
  <p>My intuition tells me I have to set a range [min : max] of adjacent pixel of a color, then determine the center of that area, and plot a 'O' in it...</p>
  <hr />
  <p>The 1st image is an example of what I get after processing a BGR image (to HSV and processing few color masks):</p>
  <p>Image before detection</p>
  <p><img src="https://i.stack.imgur.com/1iO1B.jpg" alt="" /></p>
  <p>The 2nd image is what I'm trying to plot once the area are detected.
  Yes, I added the black circle myself as an example :-)</p>
  <p>Image after detection</p>
  <p><img src="https://i.stack.imgur.com/FPpu1.jpg" alt="" /></p>