2D Features framework 4(Detecting corners location in subpixels )
目标
在本教程中，您将学习如何：
- 使用OpenCV函数cv :: cornerSubPix来查找更精确的角点位置（比整数像素更精确）。
理论
程序
#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"
#include <iostream>
using namespace cv;
using namespace std;
Mat src, src_gray;
int maxCorners = 10;
int maxTrackbar = 25;
RNG rng(12345);
const char* source_window = "Image";
void goodFeaturesToTrack_Demo( int, void* );
int main( int argc, char** argv )
{
CommandLineParser parser( argc, argv, "{@input | lena11.jpg | 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 );
namedWindow( source_window );
createTrackbar( "Max corners:", source_window, &maxCorners, maxTrackbar, goodFeaturesToTrack_Demo );
imshow( source_window, src );
goodFeaturesToTrack_Demo( 0, 0 );
waitKey();
return 0;
}
void goodFeaturesToTrack_Demo( int, void* )
{
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;
Mat copy = src.clone();
goodFeaturesToTrack( src_gray,
corners,
maxCorners,
qualityLevel,
minDistance,
Mat(),
blockSize,
gradientSize,
useHarrisDetector,
k );
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 );
}
namedWindow( source_window );
imshow( source_window, copy );
Size winSize = Size( 5, 5 );
Size zeroZone = Size( -1, -1 );
//亚像素点检测。
TermCriteria criteria = TermCriteria( TermCriteria::EPS + TermCriteria::COUNT, 40, 0.001 );
//输入，输出，尺寸，零，准则
cornerSubPix( src_gray, corners, winSize, zeroZone, criteria );
for( size_t i = 0; i < corners.size(); i++ )
{
cout << " -- Refined Corner [" << i << "] (" << corners[i].x << "," << corners[i].y << ")" << endl;
}
}