title: Error cv::SURF::SURF(double,int,int,bool,bool) in Implementation SURF with OpenCV and C++
body: <p>Possible duplicate of <a href="https://stackoverflow.com/questions/11175794/opencv-surf-function-is-not-implemented">OpenCV SURF function is not implemented</a></p>
  
  <p>My Error code is:</p>
  
  <blockquote>
    <p>error LNK2019: unresolved external symbol "public: __thiscall cv::SURF::SURF(double,int,int,bool,bool)" (??0SURF@cv@@QAE@NHH_N0@Z) referenced in function _main</p>
  </blockquote>
  
  <p>I don't know how to fix it.</p>
  
  <p>My Code is:</p>
  
  <pre><code>#include &lt;opencv\cv.h&gt;
  #include &lt;opencv\highgui.h&gt;
  #include &lt;iostream&gt;
  #include &lt;conio.h&gt;
  #include &lt;opencv2\nonfree\features2d.hpp&gt;
  #include &lt;opencv2\legacy\legacy.hpp&gt;
  #include &lt;opencv2\core\core.hpp&gt;
  #include &lt;stdio.h&gt;
  
  using namespace cv;
  using namespace std;
  
  int main()
  {
      Mat img_1 = imread("kmu1.jpg", CV_LOAD_IMAGE_GRAYSCALE);
      Mat img_2 = imread("all.jpg", CV_LOAD_IMAGE_GRAYSCALE);
  
      if(!img_1.data || !img_2.data)
      {
          cout &lt;&lt; "could not open or find the image" &lt;&lt; endl;
          return -1;
      }
  
      int minHessian = 400;
      SURF surf( minHessian );
  
      vector &lt;KeyPoint&gt; keyPoints_1, keyPoints_2;
      Mat descriptors_1, descriptors_2;
  
      surf(img_1, Mat(), keyPoints_1, descriptors_1, false);
      surf(img_2, Mat(), keyPoints_2, descriptors_2, false);
  
      BFMatcher matcher(NORM_L2, false);
      vector&lt;DMatch&gt; matches;
      matcher.match(descriptors_1, descriptors_2, matches);
  
      Mat img_matches;
      drawMatches(img_1, keyPoints_1, img_2, keyPoints_2, matches, img_matches);
  
      imshow("Matches", img_matches);
  
      waitKey(0);
      _getch();
      return 0;
  } 
  </code></pre>