void writeMatToFile(cv::Mat& m, const char* filename) 
{ 
 std::ofstream fout(filename); 
 
 if (!fout) 
 { 
 std::cout << "File Not Opened" << std::endl; 
 return; 
 } 
 
 for (int i = 0; i<m.rows; i++) 
 { 
 for (int j = 0; j<m.cols; j++) 
 { 
 fout << m.at<float>(i, j) << "\t"; 
 } 
 fout << std::endl; 
 } 
 
 fout.close(); 
}