//必须转换为8位图像
Img.convertTo(img1, CV_8UC1,255,0);
current_image.convertTo(img2,CV_8UC1,255,0);
std::vector<cv::KeyPoint> keypoints1, keypoints2;
double minDistance = 10;
int blockSize = CORNER_BLOCKSIZE, gradientSize = CORNER_BLOCKSIZE;
bool useHarrisDetector = true;
double k = 0.04;
//使用Harris角点检测 keypoints 或者 SURF ORB
//int minHessian = CANNY_LOWTHRESHOLD;
//cv::Ptr<cv::xfeatures2d::SURF> detector = cv::xfeatures2d::SURF::create();
//detector->setHessianThreshold(minHessian);
cv::Ptr<cv::GFTTDetector> detector = cv::GFTTDetector::create(
MAX_CORNERS,
CORNER_QUALITYLEVEL,
minDistance,
blockSize,
useHarrisDetector,
k );
detector->detect(img1,keypoints1);
detector->detect(img2,keypoints2);
// Calculate descriptors xfeatures2d
//cv::Ptr<cv::ORB> extractor = cv::ORB::create();
cv::Ptr<cv::xfeatures2d::FREAK> extractor =
cv::xfeatures2d::FREAK::create(true,false,30.0f,4);
cv::Mat descriptors1, descriptors2;
extractor->compute( img1, keypoints1, descriptors1 );
extractor->compute( img2, keypoints2, descriptors2 );
// Matching descriptors using Brute Force
//cv::BFMatcher matcher(cv::NORM_L2,false);
//std::vector<cv::DMatch> matches;
//matcher.match(descriptors1, descriptors2, matches);
//也可以采用KNN Matcher
cv::Ptr<cv::DescriptorMatcher> matcher =
cv::DescriptorMatcher::create(cv::DescriptorMatcher::BRUTEFORCE);
matcher->knnMatch(current_descriptors, image_template.descriptors, knn_matches, 2);
//-- Filter matches using the Lowe's ratio test
const float ratio_thresh = 0.7f;
std::vector<cv::DMatch> good_matches;
for (size_t i = 0; i < knn_matches.size(); i++)
{
if (knn_matches[i][0].distance < ratio_thresh * knn_matches[i][1].distance)
{
good_matches.push_back(knn_matches[i][0]);
}
}
//-- Draw only "good" matches
cv::Mat img_matches,img1, img2;
current_image.convertTo(img1,CV_8UC1,255,0);
image_template.Image.convertTo(img2,CV_8UC1,255,0);
cv::drawMatches( img1, current_keypoints, img2, image_template.keypoints,
good_matches, img_matches, cv::Scalar::all(-1), cv::Scalar::all(-1),
vector<char>(), cv::DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS );
图像必须转换为8bit；
可以使用不同方法检测关键点和描述子;
两种方法来进行匹配BruteForce或者FLANNBased;
OpenCV参考：https://docs.opencv.org/3.4/d3/d46/classcv_1_1Algorithm.html
