how to add open cv blobs library in Visual studio 2013.

edit

I am not able to add open cv blobs library with visual studio 2013, i need to calculate contourArea which needs blobs library ,how can i add those libraries. EDIT:-I had used all the instructions given below my contourArea() is still showing undefined,please help?

    #include <opencv2/opencv.hpp>

    #include<stdio.h>
    #include<iostream>

    using namespace std;
    using namespace cv;

   int main()
    {
        // open the image   
        cv::Mat &image= cv::imread("cancer.jpg");
        vector<vector<Point> > contours;
        cv::Canny(image, // gray-level image
            contours, // output contours
            125, // low threshold
            350);

        for(unsigned int i=0;i<contours.size(),i++)
    {
         cout << "# of contour points: " << contours[i].size() << endl ;

         for(unsigned int j=0;j<contours[i].size(),j++)
         {
             cout << "Point(x,y)=" << contours[i][j] << endl;
         }

         cout << " Area: " << contourArea(contours[i]) << endl;//its contourArea() is undefined
    }

        cvWaitKey(0);
    }