# How to count Convexity Defects ?

Hi friends, I have written some code to detect hand. This code can detect my hand and cam find convexity defects but i dont know how to count convexity defects. Please help me. i am very confuse. Please help :) Thank you so much.... :)

#include <iostream>

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include<Windows.h>
using namespace cv;
using namespace std;

int minH = 0, maxH = 20, minS = 30, maxS = 150, minV = 60, maxV = 255;
Mat frame;
int Count=0 ;
int fingers = 0;

float innerAngle(float px1, float py1, float px2, float py2, float cx1, float cy1)
{

float dist1 = std::sqrt((px1 - cx1)*(px1 - cx1) + (py1 - cy1)*(py1 - cy1));
float dist2 = std::sqrt((px2 - cx1)*(px2 - cx1) + (py2 - cy1)*(py2 - cy1));

float Ax, Ay;
float Bx, By;
float Cx, Cy;

//find closest point to C
//printf("dist = %lf %lf\n", dist1, dist2);

Cx = cx1;
Cy = cy1;
if (dist1 < dist2)
{
Bx = px1;
By = py1;
Ax = px2;
Ay = py2;

}
else {
Bx = px2;
By = py2;
Ax = px1;
Ay = py1;
}

float Q1 = Cx - Ax;
float Q2 = Cy - Ay;
float P1 = Bx - Ax;
float P2 = By - Ay;

float A =acos((P1*Q1 + P2*Q2) / (sqrt(P1*P1 + P2*P2) * sqrt(Q1*Q1 + Q2*Q2)));

A = A * 180 / CV_PI;

return A;
}

void CallbackFunc(int event, int x, int y, int flags, void* userdata)
{
Mat RGB = frame(Rect(x, y, 1, 1));
Mat HSV;
cvtColor(RGB, HSV, CV_BGR2HSV);
Vec3b pixel = HSV.at<Vec3b>(0, 0);
if (event == EVENT_LBUTTONDBLCLK) // on double left clcik
{
cout << "Click" << endl;
int h = pixel.val[0];
int s = pixel.val[1];
int v = pixel.val[2];
if (Count == 0)
{
minH = h;
maxH = h;
minS = s;
maxS = s;
minV = v;
maxV = v;
}
else
{
if (h < minH)
{
minH = h;
}
else if (h > maxH)
{
maxH = h;
}
if (s < minS)
{
minS = s;
}
else if (s > maxS)
{
maxS = s;
}
if (v < minV)
{
minV = v;
}
else if (v > maxV)
{
maxV = v;
}

}
Count++;
}
cout << pixel << endl;
}
int main()
{
cv::VideoCapture cap(0);
const char* windowName = "Fingertip detection";
cv::namedWindow(windowName);
cv::setMouseCallback(windowName, CallbackFunc, NULL);
int inAngleMin = 200, inAngleMax = 300, angleMin = 180, angleMax = 359, lengthMin = 10, lengthMax = 80;
/*   cv::createTrackbar("Inner angle min", windowName, &inAngleMin, 360);
cv::createTrackbar("Inner angle max", windowName, &inAngleMax, 360);
cv::createTrackbar("Angle min", windowName, &angleMin, 360);
cv::createTrackbar("Angle max", windowName, &angleMax, 360);
cv::createTrackbar("Length min", windowName, &lengthMin, 100);
cv::createTrackbar("Length max", windowName, &lengthMax, 100);*/
while (1)
{
cap >> frame;
cv::Mat hsv;
cv::cvtColor(frame, hsv, CV_BGR2HSV);
cv::inRange(hsv, cv::Scalar(minH, minS, minV), cv::Scalar(maxH, maxS, maxV), hsv);
// Pre processing
int blurSize = 5;
int elementSize = 5;
cv::medianBlur(hsv, hsv, blurSize);
cv::Mat element = cv::getStructuringElement(cv::MORPH_ELLIPSE, cv::Size(2 * elementSize + 1, 2 * elementSize + 1), cv::Point(elementSize, elementSize));
cv::dilate(hsv, hsv, element);
// Contour detection
vector<std::vector<cv::Point> > contours;
vector<cv::Vec4i> hierarchy;
cv::findContours(hsv, contours, hierarchy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE, cv::Point(0, 0));
size_t largestContour = 0;
for (size_t i = 1; i < contours.size(); i++)
{
if (cv::contourArea(contours ...
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       for (size_t i = 0; i < convexityDefects.size(); i++)