title: How can one display an image using cv2 in Python
body: <p>I've been working with code to display frames from a movie. The bare bones of the code is as follows:</p>
  
  <pre><code>import cv2
  import matplotlib.pyplot as plt
  
  # Read single frame avi
  cap = cv2.VideoCapture('singleFrame.avi')
  rval, frame = cap.read()
  
  # Attempt to display using cv2 (doesn't work)
  cv2.namedWindow("Input")
  cv2.imshow("Input", frame)
  
  #Display image using matplotlib (Works)
  b,g,r = cv2.split(frame)
  frame_rgb = cv2.merge((r,g,b))
  plt.imshow(frame_rgb)
  plt.title('Matplotlib') #Give this plot a title, 
                          #so I know it's from matplotlib and not cv2
  plt.show()
  </code></pre>
  
  <p>Because I can display the image using matplotlib, I know that I'm successfully reading it in. </p>
  
  <p>I don't understand why my creation of a window and attempt to show an image using cv2 doesn't work. No cv2 window ever appears. Oddly though, if I create a second cv2 window, the 'input' window appears, but it is only a blank/white window. </p>
  
  <p>What am I missing here?</p>