2D Features framework6(Feature Description )
目标
在本教程中，您将学习如何：
-
使用cv :: DescriptorExtractor接口来查找与关键点相对应的特征向量。特别：
- 使用cv :: xfeatures2d :: SURF及其函数cv :: xfeatures2d :: SURF :: compute来执行所需的计算。
- 使用cv :: DescriptorMatcher来匹配特征向量
- 使用函数cv :: drawMatches绘制检测到的匹配。
- 警告
- 您需要OpenCV contrib模块才能使用SURF功能（备选方案是ORB，KAZE ...功能）。
理论
程序
#include <iostream>
#include "opencv2/core.hpp"
#ifdef HAVE_OPENCV_XFEATURES2D
#include "opencv2/highgui.hpp"
#include "opencv2/features2d.hpp"
#include "opencv2/xfeatures2d.hpp"
using namespace cv;
using namespace cv::xfeatures2d;
using std::cout;
using std::endl;
const char* keys =
"{ help h | | Print help message. }"
"{ input1 | box.png | Path to input image 1. }"
"{ input2 | box_in_scene.png | Path to input image 2. }";
int main( int argc, char* argv[] )
{
CommandLineParser parser( argc, argv, keys );
Mat img1 = imread( parser.get<String>("input1"), IMREAD_GRAYSCALE );
Mat img2 = imread( parser.get<String>("input2"), IMREAD_GRAYSCALE );
if ( img1.empty() || img2.empty() )
{
cout << "Could not open or find the image!\n" << endl;
parser.printMessage();
return -1;
}
//-- Step 1: Detect the keypoints using SURF Detector, compute the descriptors
int minHessian = 400;
Ptr<SURF> detector = SURF::create( minHessian );
std::vector<KeyPoint> keypoints1, keypoints2;
Mat descriptors1, descriptors2;
//检测关键点，并计算描述符
detector->detectAndCompute( img1, noArray(), keypoints1, descriptors1 );
detector->detectAndCompute( img2, noArray(), keypoints2, descriptors2 );
//-- Step 2: Matching descriptor vectors with a brute force matcher
// Since SURF is a floating-point descriptor NORM_L2 is used
//初始化参数是一个匹配器的类型参数
Ptr<DescriptorMatcher> matcher = DescriptorMatcher::create(DescriptorMatcher::BRUTEFORCE);
std::vector< DMatch > matches;
//输入，输入，输出
matcher->match( descriptors1, descriptors2, matches );
//-- Draw matches
Mat img_matches;
//最后是输出
drawMatches( img1, keypoints1, img2, keypoints2, matches, img_matches );
//-- Show detected matches
imshow("Matches", img_matches );
waitKey();
return 0;
}
#else
int main()
{
std::cout << "This tutorial code needs the xfeatures2d contrib module to be run." << std::endl;
return 0;
}
#endif