main.cpp

#include <iostream>
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/core/core.hpp"

using namespace std;
using namespace cv;

int main(int argc, char **argv) {
  Mat image;
  image = imread("chessboard.png", CV_LOAD_IMAGE_COLOR);   // Read the file

  if(!image.data) {
    cerr << "Unable to find image" << endl;
    return -1;
  }

  namedWindow("original", CV_WINDOW_AUTOSIZE);
  imshow("original", image);

  Mat grayImage;
  cvtColor(image, grayImage, CV_BGR2GRAY);

  Mat harrisImage;
  cornerHarris(grayImage, harrisImage, 2, 3, 0.04);

  namedWindow("harris", CV_WINDOW_AUTOSIZE);
  vector<Mat> channels;

  Mat normalized;
  normalize(harrisImage, normalized, 0, 255, NORM_MINMAX, CV_32FC1, Mat() );

  /// Drawing a circle around corners
  for( int j = 0; j < normalized.rows ; j++ ) {
    for( int i = 0; i < normalized.cols; i++ ) {
      if( (int) normalized.at<float>(j,i) > 200 ) {
         circle(image, Point( i, j ), 8,  Scalar(0, 0, 0xff), 1, 1, 0 );
      }
    }
  }

  imshow("harris", image);


  while(true) {
    if (waitKey(30) == 27)
    {
      cout << "esc key is pressed by user" << endl;
      break;
    }
  }

  return 0;
}