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/**
* @file CannyDetector_Demo.cpp
* @brief Sample code showing how to detect edges using the Canny Detector
* @author OpenCV team
*/
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
#include <iostream>
using namespace cv;
//![variables]
Mat src, src_gray;
Mat dst, detected_edges;
int lowThreshold = 0;
const int max_lowThreshold = 100;
const int ratio = 3;
const int kernel_size = 3;
const char* window_name = "Edge Map";
//![variables]
/**
* @function CannyThreshold
* @brief Trackbar callback - Canny thresholds input with a ratio 1:3
*/
static void CannyThreshold(int, void*)
{
//![reduce_noise]
/// Reduce noise with a kernel 3x3
blur( src_gray, detected_edges, Size(3,3) );
//![reduce_noise]
//![canny]
/// Canny detector
Canny( detected_edges, detected_edges, lowThreshold, lowThreshold*ratio, kernel_size );
//![canny]
/// Using Canny's output as a mask, we display our result
//![fill]
dst = Scalar::all(0);
//![fill]
//![copyto]
src.copyTo( dst, detected_edges);
//![copyto]
//![display]
imshow( window_name, dst );
//![display]
}
/**
* @function main
*/
int main( int argc, char** argv )
{
//![load]
CommandLineParser parser( argc, argv, "{@input | fruits.jpg | input image}" );
src = imread( samples::findFile( parser.get<String>( "@input" ) ), IMREAD_COLOR ); // Load an image
if( src.empty() )
{
std::cout << "Could not open or find the image!\n" << std::endl;
std::cout << "Usage: " << argv[0] << " <Input image>" << std::endl;
return -1;
}
//![load]
//![create_mat]
/// Create a matrix of the same type and size as src (for dst)
dst.create( src.size(), src.type() );
//![create_mat]
//![convert_to_gray]
cvtColor( src, src_gray, COLOR_BGR2GRAY );
//![convert_to_gray]
//![create_window]
namedWindow( window_name, WINDOW_AUTOSIZE );
//![create_window]
//![create_trackbar]
/// Create a Trackbar for user to enter threshold
createTrackbar( "Min Threshold:", window_name, &lowThreshold, max_lowThreshold, CannyThreshold );
//![create_trackbar]
/// Show the image
CannyThreshold(0, 0);
/// Wait until user exit program by pressing a key
waitKey(0);
return 0;
}
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