Finger tracking / counting using openCv convexity defects

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C++

recognition

Hi all, Just a quick question. I have been working on a basic hand/ finger tracking code using OpenCv and the ConvexHull and ConvexityDefects method. Basically i am able to create a contour of the hand. I now need to be able to count the number of fingers. I no that the start and the end points of the Convex Hull are the finger tips but i am unsure how to count them and also how to highlight them by drawing circles or them or something. I kinda what my code to preform something like this http://www.youtube.com/watch?v=mGpTE1RkEvQ[^]

This is a sample part of my code so far:

cvFindContours( hsv_mask, storage, &contours, sizeof(CvContour), CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE, cvPoint(0,0) );

CvSeq* contours2 = NULL;

CvRect rect = cvBoundingRect( contours2, 0 );

cvRectangle( bitImage, cvPoint(rect.x, rect.y + rect.height), cvPoint(rect.x + rect.width, rect.y), CV_RGB(200, 0, 200), 1, 8, 0 );

CvSeq* hull = cvConvexHull2( contours2, 0, CV_CLOCKWISE, 0 );

CvSeq* defect = cvConvexityDefects( contours2, hull, dftStorage );

CvBox2D box = cvMinAreaRect2( contours2, minStorage );

cvDrawContours( bg, contours2,  CV_RGB( 0, 200, 0), CV_RGB( 0, 100, 0), 1, 1, 8, cvPoint(0,0));

I have played around with it and I can now draw the fingertip points using this code

for(;defect;defect = defect->h_next) 
{ 
        int nomdef = defect->total;
        if(nomdef == 0)  
	continue; 
	defectArray = (CvConvexityDefect*)malloc(sizeof(CvConvexityDefect)*nomdef);
				
	cvCvtSeqToArray (defect, defectArray, CV_WHOLE_SEQ);
	for(i=0; i<nomdef;>
	{ 
		cvCircle( bg, *(defectArray[i].end), 5, CV_RGB(255,0,0), -1, 8,0);  
		cvCircle( bg, *(defectArray[i].start), 5, CV_RGB(0,0,255), -1, 8,0); 
		cvCircle( bg, *(defectArray[i].depth_point), 5, CV_RGB(0,255,255), -1, 8,0); 
					
	}

	j++;
	free(defectArray);
	}

However i am still getting a lot of false positives. Also if any one could suggest any methods to now count the fingers that would be wonderful

Any help would be very much appreciated
Thanks