hough circle transform error

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Hello guys , I am trying to do hough circle transform in order to find pupil in eyeROI.But It doesnt work ..Do you have any idea about how to fix this problem ? Here is the code :

#include "opencv2/objdetect/objdetect.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>

using namespace std;
using namespace cv;

/** Global variables */
String face_cascade_name = "haarcascade_frontalface_alt.xml";
String eyes_cascade_name = "haarcascade_eye_tree_eyeglasses.xml";
CascadeClassifier face_cascade;
CascadeClassifier eyes_cascade;
String window_name = "Capture - Face detection";
String window_name2 = "right eye";
String window_name3 = "left eye";



Rect shrinkRect(Rect rect, int width_percent, int height_percent)
{
    if (width_percent > 100) width_percent = 100;
    if (height_percent > 100) height_percent = 100;

    Rect newrect;
    newrect.width = (rect.width * width_percent) / 100;
    newrect.height = (rect.height * height_percent) / 100;
    newrect.x = rect.x + (rect.width - newrect.width) / 2;
    newrect.y = rect.y + (rect.height - newrect.height) / 2;

    return newrect;
}

Rect expandRect(Rect rect, int width_percent, int height_percent)
{
    // not tested strongly
    Rect newrect;
    newrect.width = rect.width + ((rect.width * width_percent) / 100);
    newrect.height = rect.height + ((rect.height * height_percent) / 100);
    newrect.x = rect.x + (rect.width - newrect.width) / 2;
    newrect.y = rect.y + (rect.height - newrect.height) / 2;

    return newrect;
}

void updateEyeRects(vector<Rect> eyes, Rect& leftEyeRect, Rect& rightEyeRect)
{
    if (eyes.size() < 2) return;
    Rect intersection = eyes[0] & eyes[1];
    if (intersection.width > 1) return;

    if (eyes[0].x < eyes[1].x)
    {
        leftEyeRect = eyes[0];
        rightEyeRect = eyes[1];
    }
    else
    {
        leftEyeRect = eyes[1];
        rightEyeRect = eyes[0];
    }
}

std::vector<Rect> detectEyes(Mat frame, Rect faceRect)
{
    std::vector<Rect> faces;
    if (faceRect.width > 0)
    {
        faces.push_back(faceRect);
    }

    std::vector<Rect> eyes;
    Mat frame_gray;

    cvtColor(frame, frame_gray, COLOR_BGR2GRAY);

    //-- Detect faces
    if (faces.size() == 0)
    {
        equalizeHist(frame_gray, frame_gray);
        face_cascade.detectMultiScale(frame_gray, faces, 1.1, 2, 0, Size(80, 80));
    }

    for (size_t i = 0; i < faces.size(); i++)
    {
        faces[i].height -= faces[i].height / 2;
        faces[i].y += faces[i].height / 3;
        Mat faceROI = frame_gray(faces[i]);
        equalizeHist(faceROI, faceROI);
        //-- In each face, detect eyes
        eyes_cascade.detectMultiScale(faceROI, eyes, 1.1, 2, 0 | CASCADE_SCALE_IMAGE, Size(30, 30));

        for (size_t j = 0; j < eyes.size(); j++)
        {
            eyes[j].x += faces[i].x;
            eyes[j].y += faces[i].y;
        }
    }
    return eyes;
}






int main(int argc, char** argv)
{
    VideoCapture capture;
    Mat frame;

    //-- 1. Load the cascade
    if (!face_cascade.load(face_cascade_name))
    {
        printf("--(!)Error loading face cascade\n");
        return -1;
    };
    if (!eyes_cascade.load(eyes_cascade_name))
    {
        printf("--(!)Error loading eyes cascade\n");
        return -1;
    };

    // Read the video stream or open the web cam
    if (argc > 1)
        capture.open(argv[1]);
    else
        capture.open(0);

    if (!capture.isOpened())
    {
        printf("--(!)Error opening video capture\n");
        return -1;
    }
    Mat left_frame, right_frame;
    Rect leftEyeRect;
    Rect rightEyeRect;
    vector<Rect> eyes;
    int fail_count = 0;

    while (capture.read(frame))
    {
        double t = (double)getTickCount();
        if (frame.empty())
        {
            printf(" --(!) No captured frame -- Break!");
            break;
        }

        if ((eyes.size() < 2) & !(leftEyeRect.width & rightEyeRect.width))
        {
            putText(frame, "Searching for an eye pair..", Point(20, 20), 0, 0.6, Scalar(0, 255, 0));
            eyes = detectEyes(frame, Rect());
            updateEyeRects(eyes, leftEyeRect, rightEyeRect);
        }
        else
        {
            Rect eyesRect(leftEyeRect | rightEyeRect);
            eyesRect = expandRect(eyesRect, 30, 300);
            eyesRect = eyesRect & Rect(0, 0, frame.cols, frame ...