matlab code to generate background noise in a color image

provide the code to generate background noise ie, white spot like in a color image

Answer 1

[Image Analyst]

Were my responses in your duplicate question http://www.mathworks.com/matlabcentral/answers/76170-how-to-generate-background-noise-in-a-color-image not what you were looking for? You could have continued the discussion there instead of posting a new question like it's brand new.

Answer 2

[Michael Nauheimer]

How much noise is wanted? And do you want Gaussian white noise or just random noise?

If you image data is saved in A, I would say you could add Gaussian white noise by doing as shown below.

thesize = size(A);
noisesize = 20; % You choose!
for i = 1:3;
  Y(:,:,i) = uint8(double(A(:,:,i))+wgn(thesize(1),thesize(2),noisesize));
end

And then you output data should be in Y with white noise added.

[Image Analyst]

No, he wants salt and pepper noise like he stated in the duplicate of this: http://www.mathworks.com/matlabcentral/answers/76170-how-to-generate-background-noise-in-a-color-image