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/**
* @function goodFeaturesToTrack_Demo.cpp
* @brief Demo code for detecting corners using Shi-Tomasi method
* @author OpenCV team
*/
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"
#include <iostream>
using namespace cv;
using namespace std;
/// Global variables
Mat src, src_gray;
int maxCorners = 23;
int maxTrackbar = 100;
RNG rng(12345);
const 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
CommandLineParser parser( argc, argv, "{@input | ../data/pic3.png | input image}" );
src = imread( parser.get<String>( "@input" ) );
if( src.empty() )
{
cout << "Could not open or find the image!\n" << endl;
cout << "Usage: " << argv[0] << " <Input image>" << endl;
return -1;
}
cvtColor( src, src_gray, COLOR_BGR2GRAY );
/// Create Window
namedWindow( source_window );
/// Create Trackbar to set the number of corners
createTrackbar( "Max corners:", source_window, &maxCorners, maxTrackbar, goodFeaturesToTrack_Demo );
imshow( source_window, src );
goodFeaturesToTrack_Demo( 0, 0 );
waitKey();
return 0;
}
/**
* @function goodFeaturesToTrack_Demo.cpp
* @brief Apply Shi-Tomasi corner detector
*/
void goodFeaturesToTrack_Demo( int, void* )
{
/// Parameters for Shi-Tomasi algorithm
maxCorners = MAX(maxCorners, 1);
vector<Point2f> corners;
double qualityLevel = 0.01;
double minDistance = 10;
int blockSize = 3, gradientSize = 3;
bool useHarrisDetector = false;
double k = 0.04;
/// Copy the source image
Mat copy = src.clone();
/// Apply corner detection
goodFeaturesToTrack( src_gray,
corners,
maxCorners,
qualityLevel,
minDistance,
Mat(),
blockSize,
gradientSize,
useHarrisDetector,
k );
/// Draw corners detected
cout << "** Number of corners detected: " << corners.size() << endl;
int radius = 4;
for( size_t i = 0; i < corners.size(); i++ )
{
circle( copy, corners[i], radius, Scalar(rng.uniform(0,255), rng.uniform(0, 256), rng.uniform(0, 256)), FILLED );
}
/// Show what you got
namedWindow( source_window );
imshow( source_window, copy );
}