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/**
* @file houghlines.cpp
* @brief This program demonstrates line finding with the Hough transform
*/
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"
using namespace cv;
using namespace std;
int main(int argc, char** argv)
{
// Declare the output variables
Mat dst, cdst, cdstP;
//![load]
const char* default_file = "sudoku.png";
const char* filename = argc >=2 ? argv[1] : default_file;
// Loads an image
Mat src = imread( samples::findFile( filename ), IMREAD_GRAYSCALE );
// Check if image is loaded fine
if(src.empty()){
printf(" Error opening image\n");
printf(" Program Arguments: [image_name -- default %s] \n", default_file);
return -1;
}
//![load]
//![edge_detection]
// Edge detection
Canny(src, dst, 50, 200, 3);
//![edge_detection]
// Copy edges to the images that will display the results in BGR
cvtColor(dst, cdst, COLOR_GRAY2BGR);
cdstP = cdst.clone();
//![hough_lines]
// Standard Hough Line Transform
vector<Vec2f> lines; // will hold the results of the detection
HoughLines(dst, lines, 1, CV_PI/180, 150, 0, 0 ); // runs the actual detection
//![hough_lines]
//![draw_lines]
// Draw the lines
for( size_t i = 0; i < lines.size(); i++ )
{
float rho = lines[i][0], theta = lines[i][1];
Point pt1, pt2;
double a = cos(theta), b = sin(theta);
double x0 = a*rho, y0 = b*rho;
pt1.x = cvRound(x0 + 1000*(-b));
pt1.y = cvRound(y0 + 1000*(a));
pt2.x = cvRound(x0 - 1000*(-b));
pt2.y = cvRound(y0 - 1000*(a));
line( cdst, pt1, pt2, Scalar(0,0,255), 3, LINE_AA);
}
//![draw_lines]
//![hough_lines_p]
// Probabilistic Line Transform
vector<Vec4i> linesP; // will hold the results of the detection
HoughLinesP(dst, linesP, 1, CV_PI/180, 50, 50, 10 ); // runs the actual detection
//![hough_lines_p]
//![draw_lines_p]
// Draw the lines
for( size_t i = 0; i < linesP.size(); i++ )
{
Vec4i l = linesP[i];
line( cdstP, Point(l[0], l[1]), Point(l[2], l[3]), Scalar(0,0,255), 3, LINE_AA);
}
//![draw_lines_p]
//![imshow]
// Show results
imshow("Source", src);
imshow("Detected Lines (in red) - Standard Hough Line Transform", cdst);
imshow("Detected Lines (in red) - Probabilistic Line Transform", cdstP);
//![imshow]
//![exit]
// Wait and Exit
waitKey();
return 0;
//![exit]
}
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