can't use findhomography

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Hello, I'm have code use findhomography function. It can compile but when i run it have error my code:

and my error

Please help me. Sorry because my English not good The best is give me a video to use it, thanks.

#include "opencv2/calib3d/calib3d.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/features2d/features2d.hpp"
#include <iostream>
using namespace std;
using namespace cv;

int main()
{
  Mat I1,I2,I3;
  I1=imread("D:\detect\box.png");
  I2=imread("D:\detect\box_in_scene.png");
  I3=findHomography(I1,I2,CV_RANSAC,2);
  system("PAUSE");
  return 1; 
}