OpenCV C++ Program for coin detection

The following is the explanation to the C++ code for coin detection in C++ using the tool OpenCV.

👁 Image
Things to know:

1. The code will only compile in Linux environment.
2. To run in windows, please use the file: 'coin.o' and run it in cmd. However if it does not run(problem in system architecture) then compile it in windows by making suitable and obvious changes to the code like: Use in place of .
3. Compile command: g++ -w coin.cpp -o coin.exe `pkg-config --libs opencv`
4. Run command: ./coin
5. The image containing coin/coins has to be in the same directory as the code. Before you run the code, please make sure that you have OpenCV installed on your // system.

#include "opencv2/highgui/highgui.hpp"
// highgui - an interface to video and image capturing.

#include "opencv2/imgproc/imgproc.hpp"
// imgproc - An image processing module that for linear and non-linear
 image filtering, geometrical image transformations, color space conversion and so on.
#include <iostream>
#include <stdio.h>
// The header files for performing input and output.
 
using namespace cv;
// Namespace where all the C++ OpenCV functionality resides.

using namespace std;
// For input output operations.
 
int main()
{
 Mat image;
 // Mat object is a basic image container. image is an object of Mat.

 image=imread("coin-detection.jpg",CV_LOAD_IMAGE_GRAYSCALE);
 // Take any image but make sure its in the same folder.
 // first argument denotes the image to be loaded. 
 // second argument specifies the image format as follows: 
 // CV_LOAD_IMAGE_UNCHANGED (<0) loads the image as it is. 
 // CV_LOAD_IMAGE_GRAYSCALE ( 0) loads the image in Gray scale. 
 // CV_LOAD_IMAGE_COLOR (>0) loads the image in the BGR format. 
 // If the second argument is not there, it is implied CV_LOAD_IMAGE_COLOR.

 vector coin;
 // A vector data type to store the details of coins.

 HoughCircles(image,coin,CV_HOUGH_GRADIENT,2,20,450,60,0,0 );
 // Argument 1: Input image mode
 // Argument 2: A vector that stores 3 values: x,y and r for each circle.
 // Argument 3: CV_HOUGH_GRADIENT: Detection method.
 // Argument 4: The inverse ratio of resolution.
 // Argument 5: Minimum distance between centers.
 // Argument 6: Upper threshold for Canny edge detector.
 // Argument 7: Threshold for center detection.
 // Argument 8: Minimum radius to be detected. Put zero as default
 // Argument 9: Maximum radius to be detected. Put zero as default

 int l=coin.size();
 // Get the number of coins.

 cout<<"\n The number of coins is: "<<l<<"\n\n";
 
 // To draw the detected circles.
 for( size_t i = 0; i < coin.size(); i++ )
 {
 Point center(cvRound(coin[i][0]),cvRound(coin[i][1]));
 // Detect center
 // cvRound: Rounds floating point number to nearest integer.
 int radius=cvRound(coin[i][2]);
 // To get the radius from the second argument of vector coin. 
 circle(image,center,3,Scalar(0,255,0),-1,8,0);
 // circle center
 // To get the circle outline. 
 circle(image,center,radius,Scalar(0,0,255),3,8,0);
 // circle outline
 cout<< " Center location for circle "<<i+1<<" :
 "<<center<<"\n Diameter : "<<2*radius<<"\n";
 }
 cout<<"\n";
 
 namedWindow("Coin Counter",CV_WINDOW_AUTOSIZE);
 // Create a window called 
 //"A_good_name". 
 // first argument: name of the window. 
 // second argument: flag- types: 
 // WINDOW_NORMAL : The user can resize the window. 
 // WINDOW_AUTOSIZE : The window size is automatically adjusted to fit the
 // displayed image() ), and you cannot change the window size manually. 
 // WINDOW_OPENGL : The window will be created with OpenGL support.
 
 imshow("Coin Counter",image);
 // first argument: name of the window 
 // second argument: image to be shown(Mat object)

 waitKey(0); // Wait for infinite time for a key press.

 Return 0; // Return from main function.
}

End of explanation.