Examination of the Impact of Fingerprint Spatial Area Loss on Matcher Performance in Various Mobile Identification Scenarios

Background: NIST conducted a study of the FBI Repository for Individuals of Special Concern (RISC) system using various gallery and Mobile ID [MOBID] acquisition profile combinations to examine performance characteristics of the various profiles in terms of matching effectiveness and throughput. Results: The predominant RISC operational case of Mobile ID FAP10 (fingerprint acquisition profile 10) using the left and right index fingers is at a marked disadvantage in terms of matcher performance compared to the larger FAP20 and FAP30 cases using the same fingers. In terms of false non-identification rate (FNIR), FAP10 submissions fail to identify their target approximately twice as often as FAP20 or FAP30. FAP30 appears to be best/optimal and its performance is on a par with (if not slightly better) than the uncropped control case. False positive identification rates remain relatively flat across all the cases examined. Conclusion: System false non-identification rates suffer a significant performance penalty in the typical operational case of FAP10 two index finger (2,7) capture. FNIR performance can be markedly improved by either adopting FAP20 or FAP30 capture. To preserve legacy FAP10 equipment, it may be possible to utilize four finger capture (i.e., 2,3,7,8) with the smaller FAP10 to help mitigate some of the large performance penalty incurred with FAP10 in two finger operation, but this may increase the risk of sequencing errors from additional fingers having to be captured. Utilizing additional fingers or larger FAPs can also help mitigate performance penalties when a database of only-rolled or only-flat fingerprint impressions is used rather than one populated with complete FD-249 records.