title: python OpenCV output list
body: <p>I want to get a simple python list from the pixel colors from an image the output list should be monodimensional ordered as:</p>
  
  <pre><code>output = [B1,G1,R1,B2,G2,R2,B3,G3,R3....] 
  </code></pre>
  
  <p>to get the image data:</p>
  
  <pre><code>import cv2
  image = cv2.imread('a.png')
  image
  array([[[  0,   0, 255],
          [  0,   0, 255],
          [  0,   0, 255]],
  
         [[  0, 255,   0],
          [  0, 255,   0],
          [  0, 255,   0]],
  
         [[255,   0,   0],
          [255,   0,   0],
          [255,   0,   0]]], dtype=uint8)
  
  f = image.flatten()
  f
  [array([  0,   0, 255,   0,   0, 255,   0,   0, 255,   0, 255, 0,   0,
         255,   0,   0, 255,   0, 255,   0,   0, 255,   0,   0, 255, 0, 
  </code></pre>
  
  <p>0], dtype=uint8)]</p>
  
  <p>is there a way to get:</p>
  
  <pre><code>f = [0,0,255,0,0,255,0,0,255,0,255,0,0,255,0,0,255,0,255,0,0,255,0,0,255,0,0] 
  </code></pre>