How to identify this circle edge?
<p>I am trying to identify a circle in this picture using OpenCV in python:</p>

<p><img src="https://i.stack.imgur.com/XtfWR.jpg" alt=""></p>

<p>I got this image using a web cam.
There is a logo inside of this gray circle also.That logo has same color of outer of circle (black)</p>

<p>I want to separate this gray circle and black background and draw a sharp line around the circle.</p>

<p>How can I proceed?</p>