OpenCV C++ 代码：识别图像中的圆形，测量距离和半径

#include <opencv2/opencv.hpp> #include #include #include <math.h>

using namespace cv; using namespace std;

int main() { // 读入图片 Mat img = imread('test.jpg', IMREAD_COLOR); if (img.empty()) { cout << '读取图片失败！' << endl; return -1; }

// 转为灰度图
Mat gray;
cvtColor(img, gray, COLOR_BGR2GRAY);

// 高斯滤波
Mat blur;
GaussianBlur(gray, blur, Size(5, 5), 0);

// Canny边缘检测
Mat edges;
Canny(blur, edges, 50, 150);

// 查找圆形轮廓
vector<Vec3f> circles;
HoughCircles(edges, circles, HOUGH_GRADIENT, 1, 50, 200, 50, 0, 0);

// 绘制圆形轮廓
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(img, center, radius, Scalar(0, 0, 255), 2, LINE_AA);
    circle(img, center, 3, Scalar(0, 255, 0), -1, LINE_AA);
}

// 查找刻度线
vector<Vec4i> lines;
HoughLinesP(edges, lines, 1, CV_PI / 180, 50, 50, 10);

// 计算刻度线总长度
double total_length = 0.0;
for (size_t i = 0; i < lines.size(); i++)
{
    Point pt1(lines[i][0], lines[i][1]);
    Point pt2(lines[i][2], lines[i][3]);
    line(img, pt1, pt2, Scalar(0, 255, 0), 2, LINE_AA);
    total_length += norm(pt1 - pt2);
}

// 计算基准长度
double base_length = total_length / 5.0;

// 测量面积最大的圆心到其他每一个圆的圆心的距离
double max_distance = 0.0;
Point max_center;
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]);
    double area = CV_PI * pow(radius, 2);
    if (area > max_distance)
    {
        max_distance = area;
        max_center = center;
    }
}
for (size_t i = 0; i < circles.size(); i++)
{
    Point center(cvRound(circles[i][0]), cvRound(circles[i][1]));
    double distance = norm(max_center - center) * base_length / circles[0][2];
    if (distance > max_distance)
    {
        max_distance = distance;
    }
}

// 输出圆的信息
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]);
    double distance = norm(max_center - center) * base_length / circles[0][2];
    cout << '圆心位置：' << center << '，半径大小：' << distance << 'cm' << endl;
}

// 测量任意不相同的两个圆的圆心之间的距离
double max_circle_distance = 0.0;
for (size_t i = 0; i < circles.size(); i++)
{
    for (size_t j = i + 1; j < circles.size(); j++)
    {
        Point center1(cvRound(circles[i][0]), cvRound(circles[i][1]));
        Point center2(cvRound(circles[j][0]), cvRound(circles[j][1]));
        double distance = norm(center1 - center2) * base_length / circles[0][2];
        if (distance > max_circle_distance)
        {
            max_circle_distance = distance;
        }
    }
}
cout << '任意不相同的两个圆的圆心之间的最大距离为：' << max_circle_distance << 'cm' << endl;

// 显示结果
imshow('Result', img);
waitKey(0);

return 0;

}