//Get fingertips from binary img (Reference:http://www.javaadvent.com/2012/12/hand-and-finger-detection-using-javacv.html)
    String finger2SVM(Mat img, int fingers)
    {
        String result = null;



        defectMat.fromList(defectPoints);

        List<Integer> dList = defects.toList();
        Point[] contPts = contours.get(cMaxId).toArray();
        Point pastDefVec = null;
        int i;
        for (i = 0; i < nextDefectId.size(); i++)
        {
            int currentId = nextDefectId.get(i);
            int curId = dList.get(currentId);

            Point curDefectPt = contPts[curId];
            Point curDefVec = new Point();
            curDefVec.x = curDefectPt.x - inCircle.x;
            curDefVec.y = curDefectPt.y - inCircle.y;

            if (pastDefVec != null) {
                double dotProduct = curDefVec.x*pastDefVec.x +
                        curDefVec.y*pastDefVec.y;
                double crossProduct = curDefVec.x*pastDefVec.y -
                        pastDefVec.x*curDefVec.y;
                if (crossProduct <= 0)
                    break;
            }
            pastDefVec = curDefVec;

        }

        int beginId = i;
        int currtId = 0;

        ArrayList<Point> fingerTips = new ArrayList<Point>();

        if (nextDefectId.size() > 0) {
            boolean end = false;

            for (int j = beginId; ; j++)
            {
                if (j == nextDefectId.size())
                        {

                    if (end == false) {
                        j = 0;
                        end = true;
                    }
                    else
                        break;
                }

                if ((j == beginId) && (end == true))
                    break;

                int currentId = nextDefectId.get(j);
                int curId = dList.get(currentId);

                Point resultPts = contPts[curId];
                Point fin0 = contPts[dList.get(currentId-2)];
                Point fin1 = contPts[dList.get(currentId-1)];
                fingerTips.add(fin0);
                fingerTips.add(fin1);

                Core.circle(img, resultPts, 2, new Scalar(0, 0, 255), -5);//Good defect in resultPts

                currtId++;
            }

        }

        int k = 0;
        features.clear();
        for (int j = 0; j < fingerTips.size(); )
        {
            if (k > 5) // only 5 fingers
                break;
            Point resultFingers = fingerTips.get(j);
            if ((j%2 == 0)) {
                if (j != 0) {
                    Point prevFinPoint = fingerTips.get(j-1);
                    resultFingers.x = (resultFingers.x + prevFinPoint.x)/2;
                    resultFingers.y = (resultFingers.y + prevFinPoint.y)/2;
                }
                if (j == (fingerTips.size() - 2) )
                    j++;
                else
                    j += 2;
            } else
                j++;
            Point disFinger = new Point(resultFingers.x-inCircle.x, resultFingers.y-inCircle.y);
            double dis = Math.sqrt(disFinger.x*disFinger.x+disFinger.y*disFinger.y);
            Double f1 = (disFinger.x)/inCircleRadius;
            Double f2 = (disFinger.y)/inCircleRadius;
            features.add(f1);
            features.add(f2);


            Core.line(img, inCircle, resultFingers, new Scalar(24, 77, 9), 2);
            Core.circle(img, resultFingers, 2, Scalar.all(0), -5);

            Core.putText(img, Integer.toString(count), new Point(resultFingers.x - 10, resultFingers.y - 10), Core.FONT_SIMPLEX, 0.5, Scalar.all(0));

            k++;

        }

        result = fingerSVMInput(fingers);




        return result;
    }


//Convert to SVM input file
    String fingerSVMInput(int label)
    {
        String result = Integer.toString(label) + " ";
        int i;
        for (i = 0; i < features.size(); i++)
        {
            int label = i + 1;
            result = result + label + ":" + features.get(i) + " ";
        }
        result = result + "\n";
        return result;
    }