1. A method for filtering an input image to produce an output image comprising: defining a bilateral filter comprising a spatial filter and a range filter; generating a set of power images from an input image to approximate an application of the range filter, in which pixel intensities in the input image are multiplied by each other to produce the set of power images; applying the spatial filter to the set of power image to determine responses; and combining the responses on a pixel-by-pixel basis to produce a bilaterally filtered output image.