title: Unable to use SurfFeatureDetector in OpenCV 3.0.0
body: <p>System-  </p>
  
  <ol>
  <li>Windows 8.1 64 bit machine</li>
  <li>OpenCV 3.0.0</li>
  <li>Visual Studio 12 2013</li>
  </ol>
  
  <p>I have built the openCV 3.0.0 with the contrib modules. However, when I compile this code I get errors.</p>
  
  <pre><code>#include &lt;OpenNI.h&gt;                     //used for taking in input from xtion pro live
  #include &lt;iostream&gt;
  #include &lt;opencv2\highgui\highgui.hpp&gt;  
  #include &lt;opencv2\core\core.hpp&gt;        
  #include &lt;opencv2\features2d\features2d.hpp&gt;
  #include &lt;opencv2/features2d.hpp&gt;
  #include &lt;opencv2/xfeatures2d.hpp&gt;      // these are the libraries in the new location     (they contain SURF implementation)
  #include &lt;opencv2/xfeatures2d/nonfree.hpp&gt;
  
  using namespace std;
  //using namespace openni;
  using namespace cv;
  
  int main(void)
  {
      //from sample code 
      int minHessian = 400;
  
      SurfFeatureDetector detector(minHessian);
  
      return 0;
  }
  </code></pre>
  
  <p>The error is-  </p>
  
  <blockquote>
    <p>error C2065: 'SurfFeatureDetector' : undeclared identifier</p>
  </blockquote>