kolo, srednica na obrazie, open cv

Witam, czy mógłby ktoś pomóc mi wyznaczyć długość srednicy/promienia okregu znalezionego na zdjęciu za pomocą poniższej metody.

public class metody {
        public static opencv_core.IplImage kolo(String zrodlo){
        opencv_core.IplImage src = cvLoadImage(zrodlo);
        opencv_core.IplImage gray = cvCreateImage(cvGetSize(src), 8, 1);
        cvCvtColor(src, gray, CV_BGR2GRAY);
        cvSmooth(gray, gray, CV_GAUSSIAN, 3);
        opencv_core.CvMemStorage mem = opencv_core.CvMemStorage.create();
        opencv_core.CvSeq circles = cvHoughCircles(
                gray, //Input image
                mem, //Memory Storage
                CV_HOUGH_GRADIENT, //Detection method
                1, //Inverse ratio
                100, //Minimum distance between the centers of the detected circles
                100, //Higher threshold for canny edge detector
                100, //Threshold at the center detection stage
                15, //min radius
                500 //max radius
        );
        for (int i = 0; i < circles.total(); i++) {
            opencv_core.CvPoint3D32f circle = new opencv_core.CvPoint3D32f(cvGetSeqElem(circles, i));
            opencv_core.CvPoint center = cvPointFrom32f(new opencv_core.CvPoint2D32f(circle.x(), circle.y()));
            int radius = Math.round(circle.z());
            cvCircle(src, center, radius, opencv_core.CvScalar.GREEN, 6, CV_AA, 0);
        }
        //cvShowImage("Result", src);
        cvWaitKey(0);
        return src;
    }
}