Adding Uniform Random Noise to Image

cerend=im2double(ceros);
[r,c]=size(cerend);
noise=rand(r,c)-0.22;
subplot(2,2,1);
imshow(cerend+noise);
title('[-0.22 0.22] noise range');


ceren_grayd=im2double(ceren_gray);
[r2,c2]=size(ceren_grayd);
noise1=rand(r2,c2)-0.22;
subplot(2,2,2);
imshow(ceren_grayd+noise1);
title('[-0.22 0.22] noise range');



ceren1d=im2double(ceros);
[r,c]=size(ceren1d);
noise2=rand(r,c)-0.32;
subplot(2,2,3);
imshow(ceren1d+noise2);
title('[-0.32 0.32] noise range');


ceren_grayd1=im2double(ceren_gray);
[r2,c2]=size(ceren_grayd);
noise3=rand(r2,c2)-0.32;
subplot(2,2,4);
imshow(ceren_grayd1+noise3);
title('[-0.32 0.32] noise range');
subplot(2,2,1);
imhist(ceros);
title('Original image of ceros histogram');

subplot(2,2,2);
imhist(cerend+noise);
title('Noisy image of ceros histogram');


subplot(2,2,3);
imhist(ceren_gray);
title('Original image of ceren_gray of histogram');

subplot(2,2,4);
imhist(ceren_grayd+noise1);
title('Noisy image of ceren_gray histogram');