Novel sorting network-based architectures for rank order filters

This paper presents two novel sorting network-based architectures for computing high sample rate non recursive rank order filters. The proposed architectures consist of significantly fewer comparators than existing architectures that are based on bubble-sort and Batcher´s odd-even merge sort. The reduction in the number of comparators is obtained by sorting the columns of the window only once, and by merging the sorted columns in a way such that the set of candidate elements for the output is very small. The number of comparators per output are reduced even further by processing a block of outputs at a time