1. A method for reducing an artifact in an image, the method comprising: detecting edges in the image and creating an edge image; forming a gain image using the edge image; and forming a reduced-artifact image using the gain image, wherein the step of forming the gain image further comprises, for a first pixel of the edge image, steps comprising: determining a maximum value of the edge image over a window of the edge image comprising the first pixel and at least one other pixel; performing averaging to determine an average maximum edge value and an average first edge value; and computing a gain value using a ratio of the average first edge value and the average maximum edge value.