Method and device for identifying fingerprints

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.