//紅色的HSV值
int low_H = 0，low_S = 123，low_V = 100; 
int High_H = 5，High_S = 255，High_V = 255;

cvtColor（image，src，COLOR_BGR2HSV）; //從BGR-> HSV 
inRange（src，Scalar（low_H，low_S，low_V），Scalar（High_H，High_S，High_V），src）; //二值化

GaussianBlur（src，src，Size（5,3 ），2,2）;

HoughCircles（src，circles，CV_HOUGH_GRADIENT，1,50,15,7,10,30）; 
//找圓，最后兩個參數(shù)是圓半徑范圍，20是最小圓半徑，30是最大圓半徑

#include <iostream>
#include <vector>
#include <limits>
#include <opencv2/opencv.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <string>
#include <math.h> 
#include <iomanip>
#include <cstdio>
 
#pragma comment (lib, "opencv_core2413d.lib")
#pragma comment (lib, "opencv_highgui2413d.lib")
#pragma comment (lib, "opencv_imgproc2413d.lib")
#pragma comment (lib, "opencv_video2413d.lib")
#pragma comment (lib, "opencv_features2d2413d.lib")
 
using namespace std;
using namespace cv;
 
void drawCircle(Mat &input, const vector<Vec3f> &circles);
 
int main(){
 
 Mat image, src;//加載進來的圖片
 
 vector<Vec3f> circles;//識別出來的圓，每一行是一個圓，第一列是圓心的x坐標，第二列是圓心的y坐標，第三列是圓的半徑
 image = imread("D:/code/map3.png");
 Mat result = imread("D:/code/map3.png");//結(jié)果圖
 
 //紅色的HSV值
 int low_H = 0,low_S = 123,low_V = 100;
 int High_H = 5,High_S = 255,High_V = 255;
 
 cvtColor(image, src, COLOR_BGR2HSV);//從BGR->HSV
 inRange(src, Scalar(low_H, low_S, low_V), Scalar(High_H, High_S, High_V), src);//二值化
 
 //Reduce the noise so we avoid false circle detection
 GaussianBlur(src, src, Size(5, 3), 2, 2);
 
 HoughCircles(src, circles, CV_HOUGH_GRADIENT, 1, 50, 15, 7,10,30);//找圓,最后兩個參數(shù)是圓半徑范圍，20是最小圓半徑，30是最大圓半徑
 
 drawCircle(result, circles);//畫圓
 
 namedWindow("Display window1", WINDOW_NORMAL);//展示結(jié)果
 namedWindow("Display window2", WINDOW_NORMAL);
 resizeWindow("Display window1", 1240, 680);
 resizeWindow("Display window2", 1240, 680);
 imshow("Display window1", image);
 imshow("Display window2", result);
 waitKey(0);
 
 return 0;
}
 
void drawCircle(Mat &input, const vector<Vec3f> &circles){
 for (int i = 0; i<circles.size(); i++){
 Point center(cvRound(circles[i][0]), cvRound(circles[i][1]));
 int radius = cvRound(circles[i][2]);
 circle(input, center, radius, Scalar(255, 0, 0), 3, 8, 0);
 }
}