title: How to get red channel from BGR frame opencv C++
body: <pre><code>    vector &lt;Mat&gt; sepframe;
      split(frame, sepframe );
      imshow(window_red, sepframe[2]);
      imshow(window_green, sepframe[1]);
      imshow(window_blue, sepframe[0]);
  </code></pre>
  
  <p>So using BGR i am able to extract channels but i imagined That while showing red channel, I will able to see atleast some red pixels. in all 3 channels, all i am seeing is Grayscale Images( since I passed only one channel Mat). 
  Question: How to get my imagined image .</p>