SURF 特征匹配

#include <stdio.h>
#include <iostream>
#include "opencv2/core/core.hpp"//因为在属性中已经配置了opencv等目录，所以把其当成了本地目录一样
#include <opencv2/nonfree/features2d.hpp>
#include "opencv2/highgui/highgui.hpp"
#include<opencv2/legacy/legacy.hpp>
/*这里用的是图像对图像集，注意FLANN的用法*/
using namespace cv;
using namespace std;

int main()
{
	Mat trainImage = imread("1.jpg"), trainImage_gray;
	cvtColor(trainImage, trainImage_gray, CV_BGR2GRAY);

	vector<KeyPoint> train_keypoint;
	Mat trainDescriptor;
	SurfFeatureDetector featureDector(80);//80是什么？
	featureDector.detect(trainImage_gray, train_keypoint);
	SurfDescriptorExtractor featureExtractor;

	featureExtractor.compute(trainImage_gray, train_keypoint, trainDescriptor);

	//创建基于FLANN的描述符匹配对象
	FlannBasedMatcher matcher;
	vector<Mat> train_desc_collection(1, trainDescriptor);//两个参数是什么
	matcher.add(train_desc_collection);//这两句什么意思
	matcher.train();

	VideoCapture cap("test.avi");
	unsigned int frameCount = 0;

	while (char(waitKey(1)) != ‘q‘)
	{
		int64 time0 = getTickCount();
		Mat testImage, testIMage_gray;
		cap >> testImage;
		if (testImage.empty())
			continue;
		cvtColor(testImage, testIMage_gray, CV_BGR2GRAY);

		vector<KeyPoint> test_keyPoint;
		Mat testDescriptor;
		featureDector.detect(testIMage_gray, test_keyPoint);
		featureExtractor.compute(testIMage_gray, test_keyPoint, testDescriptor);

		vector<vector<DMatch>> matches;
		matcher.knnMatch(testDescriptor, matches, 2);//对每个匹配，返回两个最近邻匹配

		vector<DMatch> goodMatches;
		for (int i = 0; i < matches.size(); i++)
		{
			if (matches[i][0].distance < 0.6*matches[i][1].distance)//第一个匹配与第二个匹配距离
				                                                    //足够小时，才认为这是一个好的匹配
				goodMatches.push_back(matches[i][0]);
		}

		Mat dstImage;
		drawMatches(testImage, test_keyPoint, trainImage, train_keypoint, goodMatches, dstImage);
		imshow("匹配窗口", dstImage);
		
		cout << cvGetTickFrequency() / (getTickCount() - time0) << endl;
	}
	


	waitKey(0);
	return 0;
}