title: how to change XYZ color space to RGB 0-255
body: <p>I have XYZ dataset like that:</p>
  
  <pre><code>[[  15.4999257    20.91432805    8.15938343]
   [  38.47211872   41.38471882    4.41641215]
   [   8.42304194   10.26972173    4.58244444]
   [  59.15345728   65.6834669    42.20671404]
   [  48.21549352   50.67621445    7.84460441]
   [  28.5987903    29.48986333   25.78866701]
   [  16.37042029   11.17896503   20.92325834]...]
  </code></pre>
  
  <p>I want to change it to RGB 0-255:</p>
  
  <pre><code>import numpy as np
  
  XYZ_to_RGB_matrix = [
      [3.24062548, -1.53720797, -0.49862860],
      [-0.96893071, 1.87575606, 0.04151752],
      [0.05571012, -0.20402105, 1.05699594]]
  
  my_rgb = (np.dot(XYZ_to_RGB_matrix, xyz_test) * 255).astype('uint8')
  </code></pre>
  
  <p>xyz_test is only one row array from XYZ dataset,</p>
  
  <p>However, I found the result didn't correspond the right label,</p>
  
  <p>for example, <code>XYZ:[  15.4999257    20.91432805    8.15938343]</code> its label is green leaf 
  but my rgb result is <code>[244 116  51]</code> it is not green, so is there some mistakes in my code?</p>