title: why the grayscale image has 3 channels
body: <p>i am performing operations on a grayscale image, and the resultant image of these operations has the same extension as the input image. for an example if the input image is <code>.jpg</code> or <code>.png</code> the output image is either <code>.jpg</code> or <code>.png</code> respectively.</p>
  
  <p>and I am converting the image into grayscale as follows:</p>
  
  <pre><code>ImgProc.cvtColor(mat, grayscale, ImgProc.COLOR_BGR2GRAY),
  </code></pre>
  
  <p>and I am checking the channels count using:</p>
  
  <pre><code>.channels()
  </code></pre>
  
  <p>the problem is when I wnat to know how many channels the image contain, despit it is a grayscale image, i always receive umber of channels = 3!!</p>
  
  <p>kindly please let me know why that is happening</p>