識別帶顏色的圓,首先需要先查詢該顏色的HSV值,
下圖部分紫色歸爲紅色了:
比如紅色:
//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;
然後將圖片從BGR轉化成HSV,接着二值化:
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
如果有噪聲可以去噪(這一步可以沒有):
GaussianBlur(src,src,Size(5,3 ),2,2);
接着用HoughCircles來找圓,後面的參數可以根據需要自己設置:
HoughCircles(src,circles,CV_HOUGH_GRADIENT,1,50,15,7,10,30); //找圓,最後兩個參數是圓半徑範圍,20是最小圓半徑,30是最大圓半徑
HoughCircles介紹:
HoughCircles
(image,method,dp,minDist [,circles [,param1 [,param2 [,minRadius [,maxRadius]]]]])
參數: |
|
---|
完整代碼:
#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座標,第二列是圓心的y座標,第三列是圓的半徑
image = imread("D:/code/map3.png");
Mat result = imread("D:/code/map3.png");//結果圖
//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,最後兩個參數是圓半徑範圍,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);
}
}