title: Find color distance with deltaE_ciede2000 in Tensorflow
body: <p>In python, I can use this code to determine the color distance between two images
  but I have no idea how to do in with TensorFlow
  (I already have a function to convert tensor from RGB to LAB color space)</p>
  <pre><code>from skimage.color import deltaE_ciede2000
  import cv2
  
  im1 = cv2.imread('image1.jpg')
  im2 = cv2.imread('image2.jpg')
  im1_lab = cv2.cvtColor(im1, cv2.COLOR_BGR2LAB).astype(np.float32)
  im2_lab = cv2.cvtColor(im2, cv2.COLOR_BGR2LAB).astype(np.float32)
  color_dist = deltaE_ciede2000(im1_lab, im2_lab).mean()
  print('color distance:', color_dist)
  </code></pre>