How to add additive noise to an image? I have the following image I and I want to add additive noise using the array N below. Can you please give me a calculation example of how to achieve this?

Do I have to move from image space to frequency space?

Thank you in advance!
You don't have to go to the frequency domain to add noise. I'm not completely sure what you mean by adding it, because those number in N are quite big. Are those variances or actually sample values?

Adding them together can simply be done by well... adding them together (value by value). Since they both have the same size, this is possible.

Normally one would give a noise distribution with its paramters. Those random numbers can then be generated and added to each element of the matrix.