title: How to implement ZCA Whitening? Python
body: <p>Im trying to implement <strong>ZCA whitening</strong> and found some articles to do it, but they are a bit confusing.. can someone shine a light for me? </p>
  
  <p>Any tip or help is appreciated!</p>
  
  <p>Here is the articles i read :</p>
  
  <p><a href="http://courses.media.mit.edu/2010fall/mas622j/whiten.pdf" rel="noreferrer">http://courses.media.mit.edu/2010fall/mas622j/whiten.pdf</a>
  <a href="http://bbabenko.tumblr.com/post/86756017649/learning-low-level-vision-feautres-in-10-lines-of" rel="noreferrer">http://bbabenko.tumblr.com/post/86756017649/learning-low-level-vision-feautres-in-10-lines-of</a></p>
  
  <p>I tried several things but most of them i didnt understand and i got locked at some step.
  Right now i have this as base to start again :</p>
  
  <pre><code>dtype = np.float32
  data = np.loadtxt("../inputData/train.csv", dtype=dtype, delimiter=',', skiprows=1)
  img = ((data[1,1:]).reshape((28,28)).astype('uint8')*255)
  </code></pre>