A method of identifying fingerprints, the method including the steps of: acquiring a test image (20) formed by a number of test points characterized by different grey levels defining a test surface; determining significant points (21) in the test image; and verifying the similarity (22) between regions surrounding the significant points and corresponding regions of a reference image whose points present different grey levels defining a reference surface. The similarity between the regions (22) is verified by computing the integral norm of portions of the test and reference surfaces; and the integral norm is computed using flash cells (42, 43) programmed with a threshold value correlated to the value of the grey levels in the reference region, by biasing (56) the flash cells with a voltage value correlated to the grey level in the test region, and measuring the charge flowing through the flash cells.
Method and device for identifying fingerprints
KOVACS VAJNA, Zsolt Miklos
2003-01-01
Abstract
A method of identifying fingerprints, the method including the steps of: acquiring a test image (20) formed by a number of test points characterized by different grey levels defining a test surface; determining significant points (21) in the test image; and verifying the similarity (22) between regions surrounding the significant points and corresponding regions of a reference image whose points present different grey levels defining a reference surface. The similarity between the regions (22) is verified by computing the integral norm of portions of the test and reference surfaces; and the integral norm is computed using flash cells (42, 43) programmed with a threshold value correlated to the value of the grey levels in the reference region, by biasing (56) the flash cells with a voltage value correlated to the grey level in the test region, and measuring the charge flowing through the flash cells.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.