Fingerprint pre-processing on a hexagonal grid

A procedure for fingerprint preprocessing on a hexagonal grid is presented. The procedure consists of four stages: filtering to smooth the fingerprint ridges; adaptive segmentation to separate the foreground from the background ridges; noise removal eliminating pores and spurs; and thinning that reduces the ridges to a width of one pixel. Each stage of the procedure is explained in detail along with the appropriate diagrams. It is found that the algorithms are fast and efficient and give promising results when implemented on a hexagonal grid