1. A method of processing a medical image, the medical image comprising a plurality of pixel values, the method comprising: (a) deriving a plurality of dominant directions of image structure from the medical image, wherein each dominant direction is derived from differences between pixel-values in one of a plurality of small regions throughout the medical image and independently of information outside the image; and (b) providing processed pixel values throughout the medical image, wherein the processed pixel values are determined from the derived plurality of dominant directions by taking into account amounts of directionality of the dominant directions so that weak direction structures in the image are substantially discarded and strong directional structures in the image are substantially preserved, whereby a processed medical image is provided.