Matlab code for adding Gaussian noise of 30 db

To an image I want to add the Gaussian noise of 5db to 50 db.Tried with the following code. But in the output image display,the output is common for 5db and 50 db

I = im2double(imread(('D:\Nithya\Original Brodatz\D001.gif')));

varI = std2(I)^2;

SNRdB = 5;

for i=1:numel(SNRdB)

sigma_noise = sqrt(varI/10^(SNRdB(i)/10));

N = sigma_noise*randn(size(I));

IN1 = I+N; % using randn

IN2 = imnoise(I, 'Gaussian', 0, sigma_noise^2); % using imnoise

imshow([IN1 IN2])

title(['SNR = ' int2str(SNRdB(i)) 'dB' ...

', \sigma_{noise} = ' num2str(sigma_noise)]);

end

Answer 1

[Image Analyst]

SNRdB is not a vector, so it makes no sense to do SNRdB(i) in your loop. You will only get one value, whatever value it is, not both 5 and 50.