OpenCV speed traffic sign detection

Question

I have a problem detecting speed traffic signs with opencv 2.4 for Android. I do the following:

\"capture frame -> convert it to HSV -> extract red areas -> detect

Answer 1

private void findEllipses(Mat input){
    Mat thresholdOutput = new Mat();
    int thresh = 150;

    List contours = new ArrayList();
    MatOfInt4 hierarchy = new MatOfInt4();

    Imgproc.threshold(source, thresholdOutput, thresh, 255, Imgproc.THRESH_BINARY);
    //Imgproc.Canny(source, thresholdOutput, 50, 180);
    Imgproc.findContours(source, contours, hierarchy, Imgproc.RETR_LIST, Imgproc.CHAIN_APPROX_SIMPLE);
//      source = thresholdOutput;
    RotatedRect minEllipse[] = new RotatedRect[contours.size()];

    for(int i=0; i minEllipseSize && temp.size().height < maxEllipseSize){
            double a = Imgproc.fitEllipse(temp).size.height;
            double b = Imgproc.fitEllipse(temp).size.width;
            if(Math.abs(a - b) < 10)
                minEllipse[i] = Imgproc.fitEllipse(temp);
        }
    }

    detectedObjects.clear();
    for( int i = 0; i< contours.size(); i++ ){
        Scalar color = new Scalar(180, 255, 180);
        if(minEllipse[i] != null){
            detectedObjects.add(new DetectedObject(minEllipse[i].center));
            DetectedObject detectedObj = new DetectedObject(minEllipse[i].center);
            Core.ellipse(source, minEllipse[i], color, 2, 8);
        }
    }
}