Fast median filtering algorithms for mesh computers

摘要

Two fast algorithms for median filtering of images using parallel computers having 2-D mesh interconnections are given. Both algorithms assume that an n × n image is loaded onto the mesh with one processing element per pixel. One algorithm performs median filtering over d × d neighborhoods in O(d2) time and works with pixel values in an arbitrarily large range. This algorithm, while theoretically suboptimal, achieves a lower constant than a previously published asymptotically—optimal algorithm and is simpler to program. The second algorithm assumes that the range of pixel values is limited and relatively small, and it accomplishes median filtering in O(d) time.