All-digital ring-wedge detector applied to fingerprint recognition

An all-digital ring-wedge detector system is presented that simulates the a nalog multielement array commonly used in coherent optoelectronic processor s. 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. Al so, the system is applied on windowed subregions of fingerprint imagery, pr oviding a feature set that summarizes localized information about spatial-f requency content and edge-angle correlations. Examples are presented in whi ch this localized spatial-frequency information is used to produce local ri dge-orientation maps and to detect regions of poor print quality. In summar y, both direct-image data and spatial-transform data are found to be import ant. (C) 1999 Optical Society of America.