title: opencv 3.1.0 SurfFeatureDetector error
body: <p>İ am using this link of code <a href="https://github.com/doczhivago/rtObjectRecognition/blob/master/main.cpp" rel="nofollow">github main</a></p>
  
  <pre><code>SurfFeatureDetector detector(minH);
          detector.detect(object, kpObject);
  </code></pre>
  
  <p>But i am taking this error error: 'SurfFeatureDetector' was not declared in this scope</p>