title: Why after the openCV grayscale process, the channel disappered?
body: <p>I think the question might be super easy for some people, for me.. I can't figure it out, </p>
  
  <p>Should it be 1 channel after processing like BGR2GRAY function?</p>
  
  <pre class="lang-py prettyprint-override"><code>src = cv.imread("face.jpg", 0)
  print(src.shape)
  
  &gt;&gt;&gt;(625, 616)
  </code></pre>