void salt(cv::Mat image, int n)

void salt(cv::Mat image, int n) {
 int i,j;
  for (int k=0; k<n; k++) {  // rand() is the random number generator
   i= std::rand()%image.cols;
   j= std::rand()%image.rows;   if (image.type() == CV_8UC1) { // gray-level image
   image.at<uchar>(j,i)= 255; 
  } else if (image.type() == CV_8UC3) { // color image
   image.at<cv::Vec3b>(j,i)[0]= 255; 
    //image.at<cv::Vec3b>(j,i)[1]= 255; 
    //image.at<cv::Vec3b>(j,i)[2]= 255; 
    cv::Mat_<cv::Vec3b> im2(image);
    im2(j,i)[1]=255;
    im2(j,i)[2]=255;  }
  }
 }