opencv 如何检测hough圆内的的颜色 能给个具体的代码例子吗 谢谢大噶了

然后我该怎么检测圆里面的颜色呢 请给个具体例子谢谢 新手小白真的搞不懂

 while (1)
{
    cap >> frame;
    if (frame.empty())
        break;
    frame1 = frame.clone();
    dst = Mat::zeros(frame.size(), frame.type());
    mask = Mat::zeros(frame.size(), CV_8U);
    cvtColor(frame, gray, COLOR_BGR2GRAY);
    vector<Vec3f> circles;
    HoughCircles(gray, circles, HOUGH_GRADIENT, 1, 10, 40, 40, 10, 25);
    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(mask, center, radius, Scalar(255), -1);
        frame1.copyTo(dst, mask);
        //绘制圆心
        circle(frame, center, 3, Scalar(0, 255, 0), -1, 8, 0);
        //绘制圆的轮廓
        circle(frame, center, radius, Scalar(155, 50, 255), 3, 8, 0);
        circle(mask, center, radius, Scalar(255), -1);
    }