#include <stdio.h>

 #include <iostream>

 #include "opencv2/core/core.hpp"

 #include "opencv2/features2d/features2d.hpp"

 #include "opencv2/highgui/highgui.hpp"

 using namespace cv;

 void readme();

 /** @function main */

 int main( int argc, char** argv )

 {

   if( argc !=  )

   { readme(); return -; }

   Mat img_1 = imread( argv[], CV_LOAD_IMAGE_GRAYSCALE );

   Mat img_2 = imread( argv[], CV_LOAD_IMAGE_GRAYSCALE );

   if( !img_1.data || !img_2.data )

   { std::cout<< " --(!) Error reading images " << std::endl; return -; }

   //-- Step 1: Detect the keypoints using SURF Detector

   int minHessian = ;

   SurfFeatureDetector detector( minHessian );

   std::vector<KeyPoint> keypoints_1, keypoints_2;

   detector.detect( img_1, keypoints_1 );

   detector.detect( img_2, keypoints_2 );

   //-- Draw keypoints

   Mat img_keypoints_1; Mat img_keypoints_2;

   drawKeypoints( img_1, keypoints_1, img_keypoints_1, Scalar::all(-), DrawMatchesFlags::DEFAULT );

   drawKeypoints( img_2, keypoints_2, img_keypoints_2, Scalar::all(-), DrawMatchesFlags::DEFAULT );

   //-- Show detected (drawn) keypoints

   imshow("Keypoints 1", img_keypoints_1 );

   imshow("Keypoints 2", img_keypoints_2 );

   waitKey();

   return ;

   }

   /** @function readme */

   void readme()

   { std::cout << " Usage: ./SURF_detector <img1> <img2>" << std::endl; }