1 #include <highgui.h>
   2 #include "opencv2/core/core.hpp"
   3 #include "opencv2/calib3d/calib3d.hpp"
   4 #include "opencv2/imgproc/imgproc.hpp"
   5 #include "features_2d/features_2d.h"
   6 #include <iostream>
   7 
   8 using namespace cv;
   9 using namespace std;
  10 namespace f2d = features_2d;
  11 
  12 #define DRAW_RICH_KEYPOINTS_MODE     0
  13 #define DRAW_OUTLIERS_MODE           0
  14 
  15 const string winName = "correspondences";
  16 
  17 void drawMatchesOnly(const cv::Mat& image1, const std::vector<cv::KeyPoint>& keypoints1,
  18                  const cv::Mat& image2, const std::vector<cv::KeyPoint>& keypoints2,
  19                  const std::vector<f2d::Match>& matches, cv::Mat& display)
  20 {
  21   // Set up composite image
  22   display = cv::Mat::zeros(std::max(image1.rows, image2.rows), image1.cols + image2.cols, CV_8UC3);
  23   cv::Mat sub_display1 = display( cv::Rect(0, 0, image1.cols, image1.rows) );
  24   cv::Mat sub_display2 = display( cv::Rect(image1.cols, 0, image2.cols, image2.rows) );
  25   
  26   cvtColor(image1, sub_display1, CV_GRAY2BGR);
  27   cvtColor(image2, sub_display2, CV_GRAY2BGR);
  28 
  29   // Draw lines between matches
  30   int shift_bits = 4;
  31   int multiplier = 1 << shift_bits;
  32   for (std::vector<f2d::Match>::const_iterator i = matches.begin(), ie = matches.end(); i != ie; ++i) {
  33     const cv::KeyPoint& keypt1 = keypoints1[i->index1];
  34     const cv::KeyPoint& keypt2 = keypoints2[i->index2];
  35     cv::Point center1(keypt1.pt.x * multiplier, keypt1.pt.y * multiplier);
  36     cv::Point center2((keypt2.pt.x + image1.cols) * multiplier, keypt2.pt.y * multiplier);
  37     cv::Scalar color(std::rand() % 256, std::rand() % 256, std::rand() % 256);
  38     cv::line(display, center1, center2, color, 1, CV_AA, shift_bits);
  39   }
  40 }
  41 
  42 int main(int argc, char** argv)
  43 {
  44     if( argc != 4 )
  45     {
  46         cout << "Format:" << endl;
  47         cout << argv[0] << " [image1] [image2] [ransacReprojThreshold]" << endl;
  48 
  49         return -1;
  50     }
  51     double ransacReprojThreshold = atof(argv[3]);
  52 
  53     cout << "< Creating detector, descriptor extractor and descriptor matcher ..." << endl;
  54     f2d::SurfFeatureDetector detector;
  55     f2d::SurfDescriptorExtractor descriptorExtractor;
  56     f2d::BruteForceMatcher<f2d::L2<float> > descriptorMatcher;
  57 
  58     cout << "< Reading the images..." << endl;
  59     Mat img1 = imread( argv[1], 0 );
  60     Mat img2 = imread( argv[2], 0 );
  61     cout << ">" << endl;
  62     if( img1.empty() || img2.empty() )
  63     {
  64         cout << "Can not read images" << endl;
  65         return -1;
  66     }
  67 
  68     cout << endl << "< Extracting keypoints from the first image..." << endl;
  69     vector<KeyPoint> keypoints1;
  70     detector.detect( img1, keypoints1 );
  71     cout << keypoints1.size() << " points" << endl << ">" << endl;
  72 
  73     cout << "< Computing descriptors for keypoints from the first image..." << endl;
  74     Mat descriptors1;
  75     descriptorExtractor.compute( img1, keypoints1, descriptors1 );
  76     cout << ">" << endl;
  77 
  78     cout << endl << "< Extracting keypoints from the second image..." << endl;
  79     vector<KeyPoint> keypoints2;
  80     detector.detect( img2, keypoints2 );
  81     cout << keypoints2.size() << " points" << endl << ">" << endl;
  82 
  83     cout << "< Computing descriptors for keypoints from the second image..." << endl;
  84     Mat descriptors2;
  85     descriptorExtractor.compute( img2, keypoints2, descriptors2 );
  86     cout << ">" << endl;
  87     
  88     vector<f2d::Match> matches;
  89     descriptorMatcher.matchWindowless(descriptors1, descriptors2, matches);
  90         
  91     vector<Point2f> points1, points2;
  92     for(size_t i = 0; i < matches.size(); i++)
  93     {
  94     	points1.push_back(keypoints1[matches[i].index1].pt);
  95     	points2.push_back(keypoints2[matches[i].index2].pt);
  96     }
  97     Mat H = findHomography(Mat(points1), Mat(points2), CV_RANSAC, ransacReprojThreshold);
  98     Mat points1Projected;
  99     perspectiveTransform(Mat(points1), points1Projected, H);
 100     
 101     vector<f2d::Match> matchesFiltered;
 102     for(size_t i = 0; i < points1.size(); i++)
 103     {
 104     	Point2f point1 = points1Projected.at<Point2f>(i, 0);
 105     	double dist = norm(point1 - points2[i]);
 106     	if(dist < ransacReprojThreshold)
 107     	{
 108     		matchesFiltered.push_back(matches[i]);
 109     	}
 110     }
 111 
 112     namedWindow(winName, 1);
 113     Mat drawImg;
 114     drawMatchesOnly(img1, keypoints1, img2, keypoints2, matchesFiltered, drawImg);
 115     imshow(winName, drawImg);
 116     waitKey(0);
 117 
 118     return 0;
 119 }