How to delete additional circles in OpenCV's Finger Detection?

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i'm developing an app to recognize hand gestures... My program detect 3 useless points.. how can I make sure they are not detected?

i am using opencv 4.0.1 and microsoft visual studio 2017.

this is the code:

//FIND CONVEX HULLS
int largestcontour = 0; int maxarea = 0; 
for (int i = 0; i < contours.size(); i++) {
     double a = contourArea(contours[i]);
     if (a > maxarea)
     {
         maxarea = a;
         largestcontour = i;
     } }

 vector<vector<Point> hull(contours.size());
vector<vector<int> >  hullsI(contours.size());
 vector<vector<Vec4i>>  defects(contours.size());

 for (int i = 0; i < contours.size(); i++) {
     convexHull(contours[i], hull[i], false);
     convexHull(contours[i], hullsI[i], false);
     if (hullsI[i].size() > 3)
     {
         convexityDefects(contours[i], hullsI[i], defects[i]);
     } }

 if (maxarea > 100) {
     drawContours(drawing, hull, largestcontour, Scalar(255, 0, 255),
 3, 8, vector<Vec4i>(), 0, Point());

     for (int j = 0; j < defects[largestcontour].size(); ++j)
     {
         const Vec4i& v = defects[largestcontour][j];
         float depth = v[3] / 256;
         if (depth > 5) //  filter defects by depth
         {
             int startidx = v[0]; Point ptStart(contours[largestcontour][startidx]);
             int endidx = v[1]; Point ptEnd(contours[largestcontour][endidx]);
             int faridx = v[2]; Point ptFar(contours[largestcontour][faridx]);

             line(drawing, ptStart, ptEnd, Scalar(0, 255, 0), 1);
             line(drawing, ptStart, ptFar, Scalar(0, 255, 0), 1);
             line(drawing, ptEnd, ptFar, Scalar(0, 255, 0), 1);

             //DRAW POINTS
             circle(drawing, ptFar, 9, Scalar(0, 255, 0), 2);
             circle(drawing, ptEnd, 9, Scalar(0, 0, 255), 2);

         }
     } }

thanks