OpenCV 亚像素级的角点检测

 1 #include "opencv2/highgui/highgui.hpp"
 2 #include "opencv2/imgproc/imgproc.hpp"
 3 #include <iostream>
 4 #include <stdio.h>
 5 #include <stdlib.h>
 6 
 7 using namespace cv;
 8 using namespace std;
 9 
10 /// Global variables
11 Mat src, src_gray;
12 
13 int maxCorners = 10;
14 int maxTrackbar = 25;
15 
16 RNG rng(12345);
17 char* source_window = "Image";
18 
19 /// Function header
20 void goodFeaturesToTrack_Demo( int, void* );
21 
22 /** @function main */
23 int main( int argc, char** argv )
24 {
25   /// Load source image and convert it to gray
26   src = imread( argv[1], 1 );
27   cvtColor( src, src_gray, CV_BGR2GRAY );
28 
29   /// Create Window
30   namedWindow( source_window, CV_WINDOW_AUTOSIZE );
31 
32   /// Create Trackbar to set the number of corners
33   createTrackbar( "Max  corners:", source_window, &maxCorners, maxTrackbar, goodFeaturesToTrack_Demo);
34 
35   imshow( source_window, src );
36 
37   goodFeaturesToTrack_Demo( 0, 0 );
38 
39   waitKey(0);
40   return(0);
41 }
42 
43 /**
44  * @function goodFeaturesToTrack_Demo.cpp
45  * @brief Apply Shi-Tomasi corner detector
46  */
47 void goodFeaturesToTrack_Demo( int, void* )
48 {
49   if( maxCorners < 1 ) { maxCorners = 1; }
50 
51   /// Parameters for Shi-Tomasi algorithm
52   vector<Point2f> corners;
53   double qualityLevel = 0.01;
54   double minDistance = 10;
55   int blockSize = 3;
56   bool useHarrisDetector = false;
57   double k = 0.04;
58 
59   /// Copy the source image
60   Mat copy;
61   copy = src.clone();
62 
63   /// Apply corner detection
64   goodFeaturesToTrack( src_gray,
65                        corners,
66                        maxCorners,
67                        qualityLevel,
68                        minDistance,
69                        Mat(),
70                        blockSize,
71                        useHarrisDetector,
72                        k );
73 
74 
75   /// Draw corners detected
76   cout<<"** Number of corners detected: "<<corners.size()<<endl;
77   int r = 4;
78   for( int i = 0; i < corners.size(); i++ )
79      { circle( copy, corners[i], r, Scalar(rng.uniform(0,255), rng.uniform(0,255),
80                                                  rng.uniform(0,255)), -1, 8, 0 ); }
81 
82   /// Show what you got
83   namedWindow( source_window, CV_WINDOW_AUTOSIZE );
84   imshow( source_window, copy );
85 
86   /// Set the neeed parameters to find the refined corners
87   Size winSize = Size( 5, 5 );
88   Size zeroZone = Size( -1, -1 );
89   TermCriteria criteria = TermCriteria( CV_TERMCRIT_EPS + CV_TERMCRIT_ITER, 40, 0.001 );
90 
91   /// Calculate the refined corner locations
92   cornerSubPix( src_gray, corners, winSize, zeroZone, criteria );
93 
94   /// Write them down
95   for( int i = 0; i < corners.size(); i++ )
96      { cout<<" -- Refined Corner ["<<i<<"]  ("<<corners[i].x<<","<<corners[i].y<<")"<<endl; }
97 }