#include <stdio.h>
#include "opencv2/core/core.hpp"
#include "opencv2/features2d/features2d.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/nonfree/nonfree.hpp"

using namespace cv;

void help()
{
	printf("\nThis program demonstrates using features2d detector, descriptor extractor and simple matcher\n"
			"Using the SURF desriptor:\n"
			"\n"
			"Usage:\n matcher_simple <image1> <image2>\n");
}

int main(int argc, char** argv)
{
	if(argc != 3)
	{
		help();
		return -1;
	}

	Mat img1 = imread(argv[1], CV_LOAD_IMAGE_GRAYSCALE);
	Mat img2 = imread(argv[2], CV_LOAD_IMAGE_GRAYSCALE);
	if(img1.empty() || img2.empty())
	{
		printf("Can't read one of the images\n");
		return -1;
	}

	// detecting keypoints
	SurfFeatureDetector detector(400);
	vector<KeyPoint> keypoints1, keypoints2;
	detector.detect(img1, keypoints1);
	detector.detect(img2, keypoints2);

	// computing descriptors
	SurfDescriptorExtractor extractor;
	Mat descriptors1, descriptors2;
	extractor.compute(img1, keypoints1, descriptors1);
	extractor.compute(img2, keypoints2, descriptors2);

	// matching descriptors
	BFMatcher matcher(NORM_L2);
    vector<DMatch> matches;
    matcher.match(descriptors1, descriptors2, matches);

	// drawing the results
	namedWindow("matches", 1);
	Mat img_matches;
	drawMatches(img1, keypoints1, img2, keypoints2, matches, img_matches);
	imshow("matches", img_matches);
	waitKey(0);

	return 0;
}