图像特征点—SIFT特征点

图像特征点—SIFT特征点

关于SIFT特征点，以下三篇博客说的非常详细，再次不再赘述。
https://mp.weixin.qq.com/s/XVB88f119gRqpwTTRvTyrA
https://mp.weixin.qq.com/s/Vx-8xsXd6aXoJupr0BEMow
https://mp.weixin.qq.com/s/8WAgDmc1R_9rGRjM9eanDg

OpenCV 代码测试

#include <iostream>
#include<opencv2/highgui/highgui.hpp>
#include<opencv2/imgproc/imgproc.hpp>
#include <opencv2/opencv.hpp> 
#include<opencv2/xfeatures2d.hpp>
#include<opencv2/core/core.hpp>
 
using namespace cv;  
using namespace std;
using namespace cv::xfeatures2d;

int main()
{
       Mat image = imread("../pig.jpg");

       Ptr<Feature2D> sift = xfeatures2d::SIFT::create();

       vector<KeyPoint> kps;
       Mat         descriptor;

       sift->detect(image,kps);
       sift->compute(image,kps,descriptor);

       Mat outImage;
       drawKeypoints(image,kps,outImage,Scalar::all(-1),0);
       imshow("SIFT",outImage);

       cout<<"特征点的数量："<<kps.size()<<endl;
       cout<<"描述子的维度:"<<descriptor.size()<<endl;


       waitKey(0);

}

测试效果

PS :Opencv中SIFT运行时直接报错问题

在用SIFT函数时，opencv报出一下错误：

OpenCV(3.4.3) Error: The function/feature is not implemented (This algorithm is patented and is excluded in this configuration; Set OPENCV_ENABLE_NONFREE CMake option and rebuild the library) in cv::xfeatures2d::SIFT::create, file D:\library\opencv-3.4.3\opencv_contrib-3.4.3\modules\xfeatures2d\src\sift.cpp, line 1207

原因是在编译opencv时没有选择 OPENCV_ENABLE_NONFREE。按照网上的说法，只要cmake时勾选这部分，然后重新编译即可。但是本机在配置了其他环境之后Opencv编译过程总是出错。

无奈之下只能调用ROS中的Opencv，调用方式如下：

set(OpenCV_DIR /opt/ros/kinetic/share/OpenCV-3.3.1-dev)
find_package(OpenCV REQUIRED)
include_directories(${OPenCV_DIRS})

参考博客：
https://blog.csdn.net/fxmfxm9304/article/details/86093564
https://blog.csdn.net/zhoukehu_CSDN/article/details/83145026