pkg load image

clear
clc

I = imread('cameraman.bmp');
I2 = I;

for i = 1 : 256
  for j = 1 : 256
    temp = randi([-50 50]);
    I2(i,j) = I(i,j) + temp;
  endfor
endfor

Imean = mean(mean(I));
Imedian = median(median(I));

Imean2 = mean(mean(I2));
Imedian2 = median(median(I2));

countSame = 0;
for i = 1 : 256
  for j = 1 : 256
    if (I(i,j)==I2(i,j))
      countSame = countSame + 1;
    end
  endfor
endfor


subplot(1,2,1), imshow(I,[0 255]), title('Original')
subplot(1,2,2), imshow(I2,[0 255]), title('Random change')