C++利用Opencv实现多个圆形检测
作者:开门大弟子
霍夫圆检测是opencv中用来检测圆的重要算法,简单的说,霍夫圆检测就是对图像中的弧线做切线,再在切点位置做切线的垂线,然后看这些垂线能交于一点的个数,这个在方法中是自己设定的
主要是利用霍夫圆检测、面积筛选等完成多个圆形检测,具体代码及结果如下。
第一部分是头文件(common.h):
#pragma once #include<opencv2/opencv.hpp> #include<opencv2/highgui.hpp> #include<iostream> using namespace std; using namespace cv; extern Mat src; void imageBasicInformation(Mat& src);//图像基本信息 const Mat houghCirclePre(Mat& srcPre);//霍夫圆检测预处理 void houghCircle(Mat& srcPreHough);//霍夫圆检测 const Mat RectCirclePre(Mat& srcPre);//面积筛选拟合圆的预处理 void AreaCircles(Mat& AreaInput);//面积筛选拟合圆检测
第二部分是主函数:
#include"common.h" Mat src; int main() { src = imread("1.jpg",1); if (src.empty()) { cout << "图像不存在!" << endl; } else { namedWindow("原图", 1); imshow("原图", src); imageBasicInformation(src); Mat srcPreHough = houghCirclePre(src); houghCircle(srcPreHough); Mat RectCir = RectCirclePre(src); AreaCircles(RectCir); waitKey(0); destroyAllWindows(); } return 0; }
第三部分为霍夫圆检测函数(hough.cpp)
主要包括输出图像的基本信息函数:void imageBasicInformation(Mat& src)
霍夫圆检测预处理函数:const Mat houghCirclePre(Mat& srcPre)
霍夫圆检测函数:void houghCircle(Mat& srcPreHough)
#include"common.h" Mat graySrc, srcPre;//灰度图,霍夫检测预处理, Mat threshold_grayaSrc;//二值化图 Mat erode_threshold_graySrc, dilate_threshold_graySrc;//二值化后腐蚀,二值化后膨胀 void imageBasicInformation(Mat& src) { int cols = src.cols; int rows = src.rows; int channels = src.channels(); cout << "图像宽为:" << cols << endl; cout << "图像高为:" << rows << endl; cout << "图像通道数:" << channels << endl; } const Mat houghCirclePre(Mat& srcPre) { double houghCirclePreTime = static_cast<double>(getTickCount()); cvtColor(srcPre, graySrc, COLOR_BGR2GRAY); GaussianBlur(graySrc, graySrc, Size(3, 3), 2, 2);//滤波 threshold(graySrc, threshold_grayaSrc, 150, 255, 1);//二值化 Mat element = getStructuringElement(MORPH_RECT, Size(15, 15)); dilate(threshold_grayaSrc, dilate_threshold_graySrc, element);//膨胀 erode(dilate_threshold_graySrc, erode_threshold_graySrc, element);//腐蚀 houghCirclePreTime = ((double)getTickCount() - houghCirclePreTime) / getTickFrequency(); cout << "霍夫圆预处理时间为:" << houghCirclePreTime << "秒" << endl; return erode_threshold_graySrc; } void houghCircle(Mat& srcPreHough) { cout << "进入霍夫圆检测" << endl; vector<Vec3f> circles; HoughCircles(srcPreHough, circles, HOUGH_GRADIENT, 1, 60, 1, 35, 0, 0); cout << "圆的个数" << circles.size() << endl; for (size_t i = 0;i < circles.size();i++) { Point center(cvRound(circles[i][0]), cvRound(circles[i][1])); int radius = cvRound(circles[i][2]); circle(src, center, 3, Scalar(0, 255, 0), -1, 8, 0);//画圆心 circle(src, center, radius, Scalar(0, 0, 255), 3, 8, 0);//画圆 } namedWindow("霍夫检测结果", 0); imshow("霍夫检测结果", src); imwrite("霍夫圆检测结果.jpg", src);//保存检测结果 }
第四部分为利用面积筛选拟合圆检测(AreaCircle.cpp)
主要包括预处理函数:const Mat RectCirclePre(Mat& srcPre)
面积筛选拟合圆检测函数:void AreaCircles(Mat& AreaInput)
#include"common.h" Mat graySrcArea, thresholdGraySrc;//灰度图像,二值化图像 Mat dilateThresholdGraySrc, erodeThresholdGraySrc;//二值化后膨胀图像,膨胀之后的腐蚀图像 const Mat RectCirclePre(Mat& srcPre) { cvtColor(srcPre, graySrcArea, COLOR_BGR2GRAY); GaussianBlur(graySrcArea, graySrcArea, Size(3, 3), 2, 2); threshold(graySrcArea, thresholdGraySrc, 100, 255, 1);//二值化,阈值要根据自己的图像自己调整 Mat element = getStructuringElement(MORPH_RECT, Size(15, 15)); dilate(thresholdGraySrc, dilateThresholdGraySrc, element);//膨胀 erode(dilateThresholdGraySrc, erodeThresholdGraySrc, element);//腐蚀 return erodeThresholdGraySrc; } void AreaCircles(Mat& AreaInput) { vector<vector<Point>> RectContours; vector<Vec4i> Hierarchy; findContours(AreaInput, RectContours, Hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0)); Mat drawing = Mat::zeros(src.size(), CV_8UC3); for (int i = 0;i < RectContours.size();i++) { double area = contourArea(RectContours[i]); cout << area << endl;//输出所有计算出来的面积,方便下一步设置阈值 if (area > 15000 && area < 100000)//根据上一步计算的阈值设置范围 { drawContours(drawing, RectContours, i, Scalar(0, 255, 0), 2,8, Hierarchy, 0, Point()); RotatedRect Rect = fitEllipse(RectContours[i]); circle(src, Rect.center, 2, Scalar(0, 255, 0), 2, 8, 0);//在原图画出圆心 ellipse(src, Rect, Scalar(0, 0, 255), 2);//在原图画出轮廓 } } namedWindow("面积筛选拟合圆", 0); imshow("面积筛选拟合圆", src); imwrite("面积筛选拟合圆.jpg", src);//保存检测结果 }
结果如下(自己画的两个圆):
原图:
以下为霍夫圆检测结果:
以下为面积筛选拟合圆结果:
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