title: How to extract R,G,B values with numpy into seperate arrays
body: <p>Suppose I have a image with some dimension <code>(1920, 1080, 3)</code> , I want to extract out R,G,B values into separate arrays <code>R , G, B</code> . I tried to do it like</p>
  
  <pre><code>for i in range(image.shape[0]):
          for j in range(image.shape[1]):
              B = np.append(B, image[i, j][0])
              G = np.append(G, image[i, j][1])
              R = np.append(R, image[i, j][2])
  </code></pre>
  
  <p>But as expected this is very slow , How can I do this with numpy in built function?</p>