Embodiments describe noise reduction methods and systems for imaging devices having a pixel array having a plurality of pixels, each pixel representing one of a plurality of captured colors and having an associated captured pixel value. Noise reduction methods filter a captured pixel value for a respective pixel based on the captured pixel values associated with pixels in a window of pixels surrounding the respective pixel. Disclosed embodiments provide a low cost noise reduction filtering process that takes advantage of the correlations among the red, green and blue color channels to efficiently remove noise while retaining image sharpness. A noise model can be used to derive a parameter of the noise reduction methods.