All-digital ring-wedge detector applied to fingerprint recognition

Abstract

An all-digital ring-wedge detector system is presented that simulates the analog multielement array commonly used in coherent optoelectronic processors. The system is applicable with either hard-copy or digital imagery. Using neural-network software, we demonstrate high accuracy for the recognition of fingerprints, including both orientation and wide-scale size-independent sortings by using ring-only and wedge-only input neurons, respectively. Also, the system is applied on windowed subregions of fingerprint imagery, providing a feature set that summarizes localized information about spatial-frequency content and edge-angle correlations. Examples are presented in which this localized spatial-frequency information is used to produce local ridge-orientation maps and to detect regions of poor print quality. In summary, both direct-image data and spatial-transform data are found to be important.

Automated taxonomic classification of phytoplankton sampled with imaging‐in‐flow cytometry

“…For the final features, we used digital diffraction pattern sampling (custom MATLAB code), previously shown to be effective for fingerprint and other pattern recognition problems (Berfanger and George 1999). We implemented a modified version of the method developed by George and Wang (1994), applied to the simplified boundary images.…”

Modified geometry of ring-wedge detector for sampling Fourier transform of fingerprints for classification using neural networks

“…The reduction in dimensionality is quite important but should be done with caution so that it contains sufficient information for the subsequent classification to be effective. Mostly the RWDs have been designed with 32 rings and 32 wedges [1,3,6]. The rings make the output rotational invariant and the wedges make them scale invariant.…”

“…Berfanger and George [3] applied RWD to fingerprint identification. O'Toole and Stark [4] sampled FT in the form of rings for textural pattern recognition.…”