OpenCV 亚像素级的角点检测

 #include "opencv2/highgui/highgui.hpp"
 #include "opencv2/imgproc/imgproc.hpp"
 #include <iostream>
 #include <stdio.h>
 #include <stdlib.h>

 using namespace cv;
 using namespace std;

 /// Global variables
 Mat src, src_gray;

 int maxCorners = ;
 int maxTrackbar = ;

 RNG rng();
 char* source_window = "Image";

 /// Function header
 void goodFeaturesToTrack_Demo( int, void* );

 /** @function main */
 int main( int argc, char** argv )
 {
   /// Load source image and convert it to gray
   src = imread( argv[],  );
   cvtColor( src, src_gray, CV_BGR2GRAY );

   /// Create Window
   namedWindow( source_window, CV_WINDOW_AUTOSIZE );

   /// Create Trackbar to set the number of corners
   createTrackbar( "Max  corners:", source_window, &maxCorners, maxTrackbar, goodFeaturesToTrack_Demo);

   imshow( source_window, src );

   goodFeaturesToTrack_Demo( ,  );

   waitKey();
   return();
 }

 /**
  * @function goodFeaturesToTrack_Demo.cpp
  * @brief Apply Shi-Tomasi corner detector
  */
 void goodFeaturesToTrack_Demo( int, void* )
 {
   if( maxCorners <  ) { maxCorners = ; }

   /// Parameters for Shi-Tomasi algorithm
   vector<Point2f> corners;
   double qualityLevel = 0.01;
   double minDistance = ;
   int blockSize = ;
   bool useHarrisDetector = false;
   double k = 0.04;

   /// Copy the source image
   Mat copy;
   copy = src.clone();

   /// Apply corner detection
   goodFeaturesToTrack( src_gray,
                        corners,
                        maxCorners,
                        qualityLevel,
                        minDistance,
                        Mat(),
                        blockSize,
                        useHarrisDetector,
                        k );

   /// Draw corners detected
   cout<<"** Number of corners detected: "<<corners.size()<<endl;
   int r = ;
   for( int i = ; i < corners.size(); i++ )
      { circle( copy, corners[i], r, Scalar(rng.uniform(,), rng.uniform(,),
                                                  rng.uniform(,)), -, ,  ); }

   /// Show what you got
   namedWindow( source_window, CV_WINDOW_AUTOSIZE );
   imshow( source_window, copy );

   /// Set the neeed parameters to find the refined corners
   Size winSize = Size( ,  );
   Size zeroZone = Size( -, - );
   TermCriteria criteria = TermCriteria( CV_TERMCRIT_EPS + CV_TERMCRIT_ITER, , 0.001 );

   /// Calculate the refined corner locations
   cornerSubPix( src_gray, corners, winSize, zeroZone, criteria );

   /// Write them down
   for( int i = ; i < corners.size(); i++ )
      { cout<<" -- Refined Corner ["<<i<<"]  ("<<corners[i].x<<","<<corners[i].y<<")"<<endl; }
 }