title: FREAK Descriptor with Opencv Python
body: <p>I was trying to implement the FREAK Descriptor in Python using Opencv. Here is the code i'm using:</p>
  
  <pre><code>def surf_freak_detect(image,hessianThreshold):
      surfDetector = cv2.SURF(hessianThreshold)
      surfDetector=cv2.GridAdaptedFeatureDetector(surfDetector,50)
      keypoints = surfDetector.detect(image,None) 
      freakExtractor = cv2.DescriptorExtractor_create('FREAK')
      keypoints,descriptors= freakExtractor.compute(image,keypoints)
      del freakExtractor
      return keypoints,descriptors
  </code></pre>
  
  <p>Is this the correct way to <strong>initialise the Freak Descriptor</strong>? By doing a little debugging I found out that the interpreter takes a very long time at Computing the Descriptors and then eventually crashes. The keypoints are detected properly. Weirdly, <strong>it works sometimes</strong> and <strong>sometimes just crashes</strong>!</p>