title: Reading .exr files in OpenCV
body: <p>I have generated some depth maps using blender and have saved z-buffer values(32 bits) in OpenEXR format. Is there any way to access values from a .exr file (pixel by pixel depth info) using OpenCV 2.4.13 and python 2.7? There is no example anywhere to be found. All I can see in documentation that this file format is supported. But trying to read such a file results in error.</p>
  
  <pre><code>new=cv2.imread("D:\\Test1\\0001.exr")
  cv2.imshow('exr',new)
  print new[0,0]
  </code></pre>
  
  <p>Error:</p>
  
  <pre><code>print new[0,0]
  TypeError: 'NoneType' object has no attribute '__getitem__'
  </code></pre>
  
  <p>and</p>
  
  <pre><code>cv2.imshow('exr',new)
  cv2.error: ..\..\..\..\opencv\modules\highgui\src\window.cpp:261: error: (-215) size.width&gt;0 &amp;&amp; size.height&gt;0 in function cv::imshow
  </code></pre>
  
  <p>Closest I found is this <a href="https://stackoverflow.com/q/2119099/6677891">link</a> and this <a href="http://answers.opencv.org/question/70643/imread-imshow-openexr-example/" rel="noreferrer">link</a>. </p>