title: OpenCV, OpponentColorDescriptorExtractor, and Python
body: <p>It's pretty simple to extract SURF descriptors using cv2 and Python. You just need to initialize the descriptor and apply it, using something along the lines of:</p>
  
  <pre><code>extractor = cv2.DescriptorExtractor_create("SURF")
  </code></pre>
  
  <p>But what about the OpponentColorDescriptorExtractor as mentioned <a href="http://docs.opencv.org/modules/features2d/doc/common_interfaces_of_descriptor_extractors.html" rel="nofollow">here, towards the bottom of the page</a>?</p>
  
  <p>I have seen C++ code to create an Opponent Color extractor <a href="http://www.morethantechnical.com/2011/08/25/a-simple-object-classifier-with-bag-of-words-using-opencv-2-3-w-code/" rel="nofollow">via this blog post</a>, but I cannot find any Python bindings to go with it.</p>
  
  <p>Does anyone know how to create an Opponent Color descriptor extractor using Python bindings?</p>