title: Histogram equalization of grayscale images with NumPy
body: <p>How to do histogram equalization for multiple grayscaled images stored in a NumPy array easily?</p>
  
  <p>I have the 96x96 pixel NumPy data in this 4D format:</p>
  
  <pre><code>(1800, 1, 96,96)
  </code></pre>