1. A method of processing image signals using an image sensor having an array of image sensor pixels and processing circuitry, wherein the array of image sensor pixels includes a first group of image sensor pixels responsive to light of a first color, a second group of image sensor pixels responsive to light of a second color, and a third group of image sensor pixels responsive to light of a third color, the method comprising: with the first group of image sensor pixels, generating first image signals in response to light of the first color; with the second group of image sensor pixels, generating second image signals in response to light of the second color; with the third group of image sensor pixels, generating third image signals in response to light of the third color; and with the processing circuitry, performing filtering operations on the first image signals, the second image signals, and the third image signals that increase noise correlations associated with first image signals, the second image signals, and the third image signals, wherein the filtering operations performed on the first, second, and third image signals that increase the noise correlations increase and decrease noise fluctuations in the first, second, and third image signals together in a correlated manner.