title: Why np.ones creates a black image?
body: <p>I want to understand what is the difference between <code>np.zeros</code>and <code>np.ones</code>. In my bellow code both create a black images. But what is the use of <code>np.zeros</code>and <code>np.ones</code>. When should i use them. What is the purpose. I know <code>np.ones</code> fill matrix with 1 but what is the purpose. What i want to create a <code>white image</code></p>
  
  <pre><code>img = np.ones((512,512,3), np.uint8)
  cv2.imshow('IMG', img)
  cv2.waitKey(0)
  cv2.destroyAllWindows()
  
  img = np.zeros((512,512,3), np.uint8)
  cv2.imshow('IMG', img)
  cv2.waitKey(0)
  cv2.destroyAllWindows()
  </code></pre>