1. A method for modifying a digital image by applying a median filter using a computer system comprising a central processor and memory comprising: allocating memory locations in said memory for a set of histograms; loading a first image data set into said memory locations for said set of histograms; computing a first plurality of median values of said first image data set from said data in said memory locations for said set of histograms; partially updating said memory locations for said set of histograms with a second image data set; and, computing a second plurality of median values of said second image data set from said updated data in said memory locations for said set of histograms.