1. A image processing method, comprising: obtaining a first set of characterization values, which represents a first group of pixels that are associated with a denoising pixel in an image; obtaining a second set of characterization values, which represents a second group of pixels that are associated with a denoising reference pixel; and using the first set of characterization values and the second set of characterization values to determine a similarity between the denoising pixel and the denoising reference pixel.