title: Seaborn takes minutes to create heatmap of pixel variance from an array of images
body: <p>I am using seaborn heatmap to display the pixel variance over an array of images (obtained from a video) but doing so takes over 10 minutes and completely freezes my office PC. I'm looking for a way of obtaining this heatmap without all of these problems.</p>
  
  <p>I've tried removing yticklabels as I saw some suggestions that that might help.</p>
  
  <pre><code>vidcap = cv2.VideoCapture('video2.mp4')
  #vidcap.set(cv2.CAP_PROP_FPS, 5)
  success,image = vidcap.read()
  count = 0
  images = []
  
  while success:
    #cv2.imwrite("frame%d.png" % count, image)     # save frame as png file      
    success, image = vidcap.read()
    if success == True:
        images.append(cv2.cvtColor(image, cv2.COLOR_BGR2GRAY))
    print('New frame: ', success)
    count += 1
  
  images = np.asarray(images)
  
  aax = sns.heatmap(images.std(axis = 0), yticklabels = False)
  plt.show()
  </code></pre>