canny_edge_detection.cpp

#include <opencv2/opencv.hpp>
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
#include <iostream>
// using namespaces to nullify use of cv::function(); syntax and std::function();
using namespace std;
using namespace cv;


Mat src, src_gray;
Mat dst, detected_edges;
int lowThreshold = 0;
const int max_lowThreshold = 100;
const int ratioo = 3;
const int kernel_size = 3;
const char* window_name = "Edge Map";
static void CannyThreshold(int, void*)
{
    blur( src_gray, detected_edges, Size(3,3) );
    Canny( detected_edges, detected_edges, lowThreshold, lowThreshold*ratioo, kernel_size );
    dst = Scalar::all(0);
    src.copyTo( dst, detected_edges);
    imshow( window_name, dst );
}
int main( int argc, char** argv )
{
  CommandLineParser parser( argc, argv, "{@input | fruits.jpg | input image}" );
  src = imread( samples::findFile("./img/aibo_2005.jpg"/*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;
  }
  dst.create( src.size(), src.type() );
  cvtColor( src, src_gray, COLOR_BGR2GRAY );
  namedWindow( window_name, WINDOW_AUTOSIZE );
  createTrackbar( "Min Threshold:", window_name, &lowThreshold, max_lowThreshold, CannyThreshold );
  CannyThreshold(0, 0);
  waitKey(0);
  return 0;
}

/*
int main()
{
    // Reading image
    Mat img = imread("./img/aibo_2005.jpg");
    // Display original image
    imshow("original Image", img);
    waitKey(0);

    // Convert to graycsale
    Mat img_gray;
    cvtColor(img, img_gray, COLOR_BGR2GRAY);
    // Blur the image for better edge detection
    Mat img_blur;
    GaussianBlur(img_gray, img_blur, Size(3,3), 0);

    // Canny edge detection
    Mat edges;
    Canny(img_blur, edges, 100, 200, 3, false);

    // Display canny edge detected image
    imshow("Canny edge detection", edges);
    waitKey(0);
}
*/