2013
John Song
Albuquerque, NM
NIST has developed the NIST Ballistics Identification System (NBIS) based on 3D topography measurements on correlation cells. The Congruent Matching Cells (CMC) method is used for ballistics identifications using three identification parameters of the paired correlation cells. The number of congruent matching cell pairs is determined by the three identification parameters associated with their thresholds. An error rate calculation procedure based on the CMC method is also proposed for the error rate report of ballistics identifications. In order to test the CMC method and to verify the proposed numerical identification criterion, 40 cartridge cases fired from handguns with 10 consecutively manufactured pistol slides are measured by a 3D confocal microscope and correlated by the CMC method. Initial tests support both the proposed CMC method and the numerical identification criterion for ballistics identifications. The proposed CMC method suggests that an empirical Identification Criterion of at least 6 matching cell pairs be used for separating the matching and non-matching topographies.