title: Feature.exe: 0xC0000005: Access violation reading location 0x0000000000000000
body: <p>I am trying to detect and extract image feature using <code>DynamicAdaptedFeatureDetector</code>, but i am receiving Access violation error. The complete error is: <code>Unhandled exception at 0x000007FEE08AB89A (opencv_features2d2411d.dll) in Feature.exe: 0xC0000005: Access violation reading location 0x0000000000000000.</code></p>
  
  <p>my sample code is: </p>
  
  <pre><code>.
  .
  .
      Ptr&lt;FeatureDetector&gt; detector;
      vector&lt;KeyPoint&gt; keypoints1, keypoints2; 
      detector = new DynamicAdaptedFeatureDetector(new FastAdjuster(10, true), 5000, 10000, 10);
      detector-&gt;detect(leftImg_roi, keypoints1);
      detector-&gt;detect(rightImg_roi, keypoints2);
  
      Ptr&lt;DescriptorExtractor&gt; extractor;
      extractor = DescriptorExtractor::create("SIFT");
      Mat descriptors1, descriptors2;
      extractor-&gt;compute(leftImg_roi, keypoints1, descriptors1);
      extractor-&gt;compute(rightImg_roi, keypoints2, descriptors2);
  
      vector&lt; vector&lt;DMatch&gt; &gt; matches;
      Ptr&lt;DescriptorMatcher&gt; matcher = DescriptorMatcher::create("BruteForce");
      matcher-&gt;knnMatch(descriptors1, descriptors2, matches, 500);
  .
  .
  .
  </code></pre>
  
  <p>Error is coming in the line: extractor->compute(rightImg_roi, keypoints2, descriptors2);</p>
  
  <p>Total detected keypoints from images are: keypoints1 = 1649 and keypoints2 = 1558</p>
  
  <p>Any idea whats wrong in my code?</p>