System and method for counting ridges in a captured print image

Abstract

A system and method for counting ridges in a captured print image frame is described. A pixel path through the captured print image frame is traversed. A hysteresis band for the pixel path is determined. A number of crossings of the determined hysteresis band is counted while traversing the pixel path. A number of print ridges based on the counted number of hysteresis band crossings is determined.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 400,103, filed Aug. 2, 2002 (Atty. Dkt. No. 1823.0680000), which is herein incorporated by reference in its entirety.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The invention relates generally to the field of fingerprint scanner technology and, more particularly, to counting ridges in a captured fingerprint image frame. [0004] 2. Background Art [0005] Biometrics are a group of technologies that provide a high level of security. Fingerprint capture and recognition is an important biometric technology. Law enforcement, banking, voting, and other industries increasingly rely upon fingerprints as a biometric to recognize or verify identity. See, Biometrics Explained, v. 2.0, G. Roethenbaugh, International Computer Society Assn. Carlisle, Pa. 1998, pages 1-34 (incorporated herein by reference in its entirety). [0006] Fingerprint scanners having...

AI Technical Summary

Benefits of technology

"The present invention is a system and method for counting fingerprint ridges in a captured fingerprint image frame. The system includes a camera for capturing the fingerprint image, a memory for storing the captured image, and a ridge counter module for traversing a pixel path through the captured image and determining a hysteresis band for the pixel path. The hysteresis band is determined based on the first and second ridge pixel value peaks and the center pixel value between them. The number of fingerprint ridges is determined based on the number of hysteresis band crossings, which is determined by sequentially detecting pixel values along the pixel path range from the hysteresis band first edge value to the hysteresis band second edge value. The system can be used with any type of print including, but not limited to a print of all or part of a finger, palm, hand, toe, and foot. The technical effect of the invention is to provide a reliable and accurate method for counting fingerprint ridges in captured fingerprint images."

Problems solved by technology

A very dry skin surface on a clean fingerprint capture surface may result in a low intensity level of reflected light.

On the other hand, an oily skin surface and / or a less-clean fingerprint capture surface may result in a high level of reflected light.

Additional factors, such as the location of the finger, the pressure applied to press the finger to the platen, and the ambient environment may affect whether an acceptable quality fingerprint image is captured.

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