I have an image. I want to modify the image in such a way that the value of each pixel is increased by a particular margin. Next I want to save the newly created image and display it. 

I tried changing each pixel value but was only able to set it to constant value. I don't want all the pixels to be constant but their value should increase by (lets say) 50.

```
#include <iostream>
#include "opencv2/highgui/highgui.hpp"

using namespace std;
using namespace cv;

int main()
{
  Mat image;
  image =   imread("/home/rohit_136/Desktop/image.jpg",CV_LOAD_IMAGE_UNCHANGED);
  for (int i = 0; i < image.cols; i++) {
    for (int j = 0; j < image.rows; j++) {
      Vec3b intensity = image.at<Vec3b>(j, i)=50
    }
  }
  return 0;
}

```