Contactless fingerprint biometrics interoperability guidance updated

The U.S. National Institute of Standards and Technology has issued recommendations to bridge the gap between contactless fingerprint biometrics capture and legacy contact-based systems. The voluntary changes to the ANSI/NIST standard first published three years ago are intended to allow images from contactless systems to be ingested and processed by existing systems with minimal changes.

The differences between images collected with contact and contactless fingerprint biometrics systems are sufficient to keep them separate, NIST says, even when they will ultimately be processed by the same system.

NIST SP 500-334r1, the “Contactless Fingerprint Capture and Data Interchange Best Practice Recommendation,” “introduces an informative pathway for the integration of images captured by these contactless devices into existing systems.”

NIST investigated contactless fingerprint biometrics systems from multiple vendors in 2019, and its findings have in part informed the latest recommendation.

The revision and extension of the ANSI/NIST standard makes minor changes to the biometric data exchange to make contactless friction ridge data “not readily ingestible by existing systems.” The changes preserve backwards-compatibility of existing biometric records, and include optional provisions for storing data from the original capture sensor in case future algorithms can improve the interoperability of images through reprocessing.

NIST cautions, however, that an equivalent to FBI Appendix F Certification for the quality and usefulness of contactless fingerprints does not exist.

The document’s capture and collection guidance addresses motion stability, background and lighting effects, and guidance is also provided for subject positioning. Fingerprint quality assessment algorithms like NFIQ2 are not to be used with contactless fingerprints.

The lack of useful information from quality assessment systems about the usefulness of contactless fingerprint biometrics is part of the benefit to the market of NIST’s initial publication of SP 500-334, Veridium’s John Callahan explained to Biometric Update at the time.

The data interchange guidance addresses ANSI/NIST Type-9, 13, 14, 15, 19 and 20 records and their structure at some length, making up nearly half of the 24-page document. A new impression type (IMP) code is provided for contactless capture, and a modified structure for each record type.

Article Topics

biometrics  |  contactless biometrics  |  fingerprint biometrics  |  fingerprint recognition  |  NIST  |  standards