Consider a noisy image
g(x,y)formed by the addition of noise
n(x,y)to an original image
f(x,y); that is
g(x,y) = f(x,y) + n(x,y)
where the assumption is that at every pair of coordinates
(x,y)the noise is uncorrelated and has zero average value.
What does it mean for noise to be uncorrelated and have zero average value. I know the term uncorrelated for random variables, and mean of probability distribution function, but I can't understand these concept for images.
How can noise have zero expected value at every pair of coordinates
(x,y), or be uncorrelated ?