Как получить доступ к точкам доступа на OpenCV Matcher?

Я использую этот алгоритм сопоставления FLANN для сопоставления точек интереса на 2 рисунках, код которых приведен ниже).

Есть момент, когда код находит список совпадающих точек:

std::vector<DMatch> good_matches;

Я хотел бы получить точки локализации (х, у) на обеих картинках. Создать карту смещения. Как я могу получить доступ к этим точкам локализации?

Ура,

#include <stdio.h>
#include <iostream>
#include "opencv2/core/core.hpp"#include "opencv2/nonfree/features2d.hpp"#include "opencv2/highgui/highgui.hpp"
using namespace cv;

void readme();

/** @function main */
int main(int argc, char** argv) {
if (argc != 3) {
readme();
return -1;
}

// Transform in GrayScale
Mat img_1 = imread(argv[1], CV_LOAD_IMAGE_GRAYSCALE);
Mat img_2 = imread(argv[2], CV_LOAD_IMAGE_GRAYSCALE);

// Checks if the image could be loaded
if (!img_1.data || !img_2.data) {
std::cout << " --(!) Error reading images " << std::endl;
return -1;
}

//-- Step 1: Detect the keypoints using SURF Detector
int minHessian = 400;

SurfFeatureDetector detector(minHessian);

std::vector<KeyPoint> keypoints_1, keypoints_2;

detector.detect(img_1, keypoints_1);
detector.detect(img_2, keypoints_2);

//-- Step 2: Calculate descriptors (feature vectors)
SurfDescriptorExtractor extractor;

Mat descriptors_1, descriptors_2;

extractor.compute(img_1, keypoints_1, descriptors_1);
extractor.compute(img_2, keypoints_2, descriptors_2);

//-- Step 3: Matching descriptor vectors using FLANN matcher
FlannBasedMatcher matcher;
std::vector<DMatch> matches;
matcher.match(descriptors_1, descriptors_2, matches);

double max_dist = 0;
double min_dist = 100;

//-- Quick calculation of max and min distances between keypoints
for (int i = 0; i < descriptors_1.rows; i++) {
double dist = matches[i].distance;
//      printf("-- DISTANCE =  [%f]\n", dist);
if (dist < min_dist)
min_dist = dist;
if (dist > max_dist)
max_dist = dist;
}

printf("-- Max dist : %f \n", max_dist);
printf("-- Min dist : %f \n", min_dist);

//-- Draw only "good" matches (i.e. whose distance is less than 2*min_dist )
//-- PS.- radiusMatch can also be used here.
std::vector<DMatch> good_matches;

for (int i = 0; i < descriptors_1.rows; i++) {
if (matches[i].distance < 2 * min_dist) {
good_matches.push_back(matches[i]);
}
}

//-- Draw only "good" matches
Mat img_matches;
drawMatches(img_1, keypoints_1, img_2, keypoints_2, good_matches,
img_matches, Scalar::all(-1), Scalar::all(-1), vector<char>(),
DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS);

//-- Show detected matches
imshow("Good Matches", img_matches);

for (int i = 0; i < good_matches.size(); i++) {
printf("-- Good Match [%d] Keypoint 1: %d  -- Keypoint 2: %d  \n", i,
good_matches[i].queryIdx, good_matches[i].trainIdx);
}

waitKey(0);

return 0;
}

/** @function readme */
void readme() {
std::cout << " Usage: ./SURF_FlannMatcher <img1> <img2>" << std::endl;
}