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The purpose of the MINEX04 test was to determine the feasibility of using minutiae data (rather than image data) as the interchange medium for fingerprint information between different fingerprint matching systems. The results of MINEX04 have implications that affect planning decisions for projects such as Personal Identity Verification (PIV). PIV was initiated by Homeland Security Presidential Directive 12 [5]. This mandated the establishment of a common identification standard for federal employees and contractors. It required interoperable use of identity credentials to control physical and logical access to federal government locations and systems.
MINEX04 was designed to evaluate whether various populations and combinations of encoding schemes, enrolled templates, probe templates, and fingerprint matchers will produce successful matches. There were two categories of encoding schemes; the first were proprietary minutiae templates generated by the participants (called vendor); the second were standard minutiae templates. These standard templates are based on INCITS (International Committee for Information Technology Standards) 378 Finger Minutiae Format for Data Interchange [6]. There were two standard template types evaluated in MINEX04, but for the purposes of this study, we focus on just the results of using the standard ‘A’ templates nicknamed “MIN:A”, which contain only the minutiae attributes {x, y, ?, type, quality}.
A total of 14 vendor participated in MINEX04. These vendor are identified in the MINEX04 report and subsequently in this report by assigned letters. The identities of these vendor are not germane to the purpose of this report, so identities are not revealed herein, however the vendor key is published in the full MINEX04 report. Each vendor had to supply NIST with a software development kit (SDK) that creates an INCITS 378 MIN: A template from an image produces a comparison score from two MIN:A templates 3 . In this way, matching accuracy could be computed and compared in combinations of three dimensions: a gallery (enrolment) template, matched to a probe (authentication) template, matched with a specific vendor’s fingerprint minutiae matcher. A simple nomenclature “XY_Z” has been adopted to represent the possible combinations, where X represents the vendor that generated the enrollment template, Y represents the vendor that generated the authentication template, and Z is the vendor that developed the template matcher. Standard template matching within MINEX04 was tested in two modes. The first comprised of standard templates being generated and matched by the same vendor, referred to as Native Matching and nicknamed “MIN:A.XX_X” The second involved testing the interoperability of matching a standard template from one vendor with a standard template generated by a different vendor and then matched potentially by yet another different vendor. While all the possible combinations of interoperability were studied in MINEX04, there is one combination that has greatest operational relevance.
This is the interoperable scenario where a subject is enrolled in vendor-P’s system, but then attempts to authenticate with a different vendor-Q’s system. This is the case when a person enrolled by one agency’s system visits and presents his credentials to a different agency. In this scenario, the subject presents his finger to vendor-Q’s system and a standard template is generated; this template is then matched to vendor-P’s enrolled template with the match being conducted by vendor-Q’s matcher. This is referred to as Scenario 1 Interoperability and nicknamed “MIN:A.YX_X”. For the purposes of this study, only MIN: A.XX_X and MIN: A.YX_X template-matcher combinations are analyzed. MINEX04 used four different and distinct collections of fingerprints (called datasets) named: POEBVA, POE, DOS, & DHS2. A description of these datasets and their NIST Fingerprint Image Quality (NFIQ) distributions are documented in the MINEX04 report. All datasets used were comprised of left and right-index fingers using live-scan plain impressions. The subject sample sizes of each dataset were 60 thousand mates and 120 thousand non-mates. The testing was performed by using the second instance of the mates as the enrollment image and the first instance as the authentication image. So for each dataset there were 60 thousand mate (genuine) template comparison scores. The non-mate scores were generated by comparing the non-mate authentication samples to the same enrollment images used with the mates. This generated 120 thousand non-mate (impostor) template comparison scores.
One and two-finger authentication was evaluated in the MINEX04 test. The two-finger comparison scores were produced in a score-level fusion process by summing a subject’s left and right-index finger comparison scores. Given a set of genuine and a set of impostor two-finger template comparison scores, performance measures of False Non-Match Rate (FNMR) and False Match Rate (FMR) were computed and Detection Error Tradeoff (DET) characteristic curves compared.
Source: US Department of Commerce National Institute of Standards and Technology 2006