使用Opencv2.4.9进行SIFT特征点提取和匹配

主要使用的类：FeatureDetector FeatureExtractor FeatureMatcher

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>  
#include <opencv2/features2d/features2d.hpp>
#include <opencv2/nonfree/nonfree.hpp>
#include <iostream>

using namespace cv;
using namespace std;

int main(){
	cv::initModule_nonfree();
	Mat img1_mat = imread("1.bmp",CV_LOAD_IMAGE_GRAYSCALE);
	Mat img2_mat = imread("2.bmp",CV_LOAD_IMAGE_GRAYSCALE);
	
	std::vector<KeyPoint> img1_keypoint,img2_keypoint;

        /*特征点检测*/
//	FeatureDetector *sift_detector = FeatureDetector::create("SIFT");
	Ptr<FeatureDetector> sift_detector = FeatureDetector::create("SIFT");
	sift_detector->detect(img1_mat,img1_keypoint);
	sift_detector->detect(img2_mat,img2_keypoint);

	/*在图片上显示特征点*/
	Mat img_kp_1,img_kp_2;
	drawKeypoints(img1_mat,img1_keypoint,img_kp_1,Scalar::all(-1),DrawMatchesFlags::DEFAULT);
	drawKeypoints(img2_mat,img2_keypoint,img_kp_2,Scalar::all(-1),DrawMatchesFlags::DEFAULT);
	imshow("sift_keypoint_image 1",img_kp_1);
	imshow("sift_keypoint_image 2",img_kp_2);

        /*特征向量提取*/
	Mat img1_descriptor,img2_descriptor;
	Ptr<DescriptorExtractor> sift_descriptor_extractor = DescriptorExtractor::create("SIFT");
	sift_descriptor_extractor->compute(img1_mat,img1_keypoint,img1_descriptor);
	sift_descriptor_extractor->compute(img2_mat,img2_keypoint,img2_descriptor);
        /*特征点匹配*/
	std::vector<DMatch> img_match;
	Ptr<DescriptorMatcher> bruteforce_matcher = DescriptorMatcher::create("BruteForce");
	bruteforce_matcher->match(img1_descriptor,img2_descriptor,img_match);

        /*在图片上显示匹配结果*/
	Mat match_img;
	drawMatches(img1_mat,img1_keypoint,img2_mat,img2_keypoint,accurate_match,match_img);
	imshow("match image",match_img);
	waitKey(0);

	system("pause");
	return 0;
}

　需要注意的地方：

如果完全按老版本的opencv的写法会出现下图中Access violation的异常，解决方法如下：

 

1.在新版本的opencv中，像SIFT，SURF等专利方法放在了单独的模块中，使用前需

　　a) include <opencv2/nonfree/nonfree.hpp>

　　b) 使用前添加语句 cv::initModule_nonfree()

　　c) 在链接库中添加 opencv_nonfree2.4.9.lib,一般在配置opencv时已经添加

2.FeatureDetector 等是三个抽象基类，不能直接实例化，也不能直接使用 *，必须用Ptr<>的方式来使用

　Ptr<FeatureDetector> sift_detector = FeatureDetector::create("SIFT");

运行结果如下：