OpenCV——Brisk特征检测、匹配与对象查找

检测并绘制特征点：

 #include <opencv2/opencv.hpp>
 #include <opencv2/xfeatures2d.hpp>
 #include <iostream>

 using namespace cv;
 using namespace cv::xfeatures2d;
 using namespace std;

 int main(int argc, char** argv) {
     Mat src = imread("test.jpg", IMREAD_GRAYSCALE);
     if (src.empty()) {
         printf("could not load image...\n");
         return -;
     }
     namedWindow("input image", CV_WINDOW_AUTOSIZE);
     imshow("input image", src);

     // BRISK特征点检测
     Ptr<BRISK> detector = BRISK::create();//创建一个BRISK类对象并初始化
     vector<KeyPoint> keypoints;
     detector->detect(src, keypoints, Mat());//找出关键点

     // 绘制关键点
     Mat keypoint_img;
     drawKeypoints(src, keypoints, keypoint_img, Scalar::all(-), DrawMatchesFlags::DEFAULT);
     imshow("KeyPoints Image", keypoint_img);

     waitKey();
     return ;
 }

匹配：

 #include <opencv2/opencv.hpp>
 #include <iostream>
 #include <math.h>

 using namespace cv;
 using namespace std;

 int main(int argc, char** argv) {
     Mat img1 = imread("fire_5.jpg", IMREAD_GRAYSCALE);
     Mat img2 = imread("数字.jpg", IMREAD_GRAYSCALE);
     if (img1.empty() || img2.empty()) {
         printf("could not load images...\n");
         return -;
     }
     imshow("box image", img1);
     imshow("scene image", img2);

     // extract akaze features
     Ptr<BRISK> detector = BRISK::create();
     vector<KeyPoint> keypoints_obj;
     vector<KeyPoint> keypoints_scene;
     Mat descriptor_obj, descriptor_scene;
     detector->detectAndCompute(img1, Mat(), keypoints_obj, descriptor_obj);
     detector->detectAndCompute(img2, Mat(), keypoints_scene, descriptor_scene);

     // matching
     FlannBasedMatcher matcher(new flann::LshIndexParams(, , ));
     //FlannBasedMatcher matcher;
     //FlannBasedMatcher matcher;
     vector<DMatch> matches;
     matcher.match(descriptor_obj, descriptor_scene, matches);

     // draw matches(key points)
     Mat akazeMatchesImg;
     /*
     drawMatches(img1, keypoints_obj, img2, keypoints_scene, matches, akazeMatchesImg);
     imshow("akaze match result", akazeMatchesImg);*/

     vector<DMatch> goodMatches;
     double minDist = , maxDist = ;
     for (int i = ; i < descriptor_obj.rows; i++) {
         double dist = matches[i].distance;
         if (dist < minDist) {
             minDist = dist;
         }
         if (dist > maxDist) {
             maxDist = dist;
         }
     }
     printf("min distance : %f", minDist);

     for (int i = ; i < descriptor_obj.rows; i++) {
         double dist = matches[i].distance;
         if (dist < max(1.5*minDist, 0.02)) {
             goodMatches.push_back(matches[i]);
         }
     }

     drawMatches(img1, keypoints_obj, img2, keypoints_scene, goodMatches, akazeMatchesImg, Scalar::all(-),
         Scalar::all(-), vector<char>(), DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS);
     imshow("good match result", akazeMatchesImg);

     waitKey();
     return ;
 }