A computed tomography (CT) imaging system is provided including processing circuitry configured to obtain a plurality of basis images that are combined to generate a target image; de-noise the basis images using a noise-reduction method to generate de-noised basis images; calculate noise maps of the basis images by subtracting the de-noised basis images from the basis images; calculate a weight for each of the noise maps using the target image and the calculated noise maps; and generate a reduced-noise target image using the target image, the calculated noise maps, and the calculated weights.