Two-dimensional median filter algorithm for parallel reconfigurable computers

A fast and flexible median filter algorithm is presented which scales well with window size. It is based on the use of image histograming. Two accumulator arrays are used to determine the median value of a discrete sequence of numbers. Speed-up factors of 3 and 4 are achieved over conventional histograming methods (those using single accumulator arrays). Two approaches have been implemented with optimisation in mind. Worst- and best-case machine performance boundaries are defined. Timings are given for both types of parallel architecture.