I am using Matlab function imnoise to add gaussian noise to one image. However, it seems that adjacent samples of the noise is correlated. I am using matlab code below to add noise.
I = imread('eight.tif'); J = imnoise(I, 'gaussian', 0, 0.02); figure; imshow(I); figure; imshow(J);
From the image, it contains many short vertical gray lines which maybe be image structures for some cases. Is the noise really additive white gaussian noise(AWGN)?