Advancing the Understanding of 3D Imaging for Firearms Identification

Houston Forensic Science Center, in collaboration with CSAFE, has been awarded an NIJ grant to conduct a study focused on comparability of images acquired by 3D instruments manufactured by different vendors. The vendors participating in this study are Cadre (TopMatch), Leeds (Evofinder), or LeadsOnline/ Ultra FT (Quantum). The main purpose of this study is to evaluate whether trained Firearms Examiners can form conclusions of Identification and/or Exclusion when virtually comparing scans acquired by different systems.  This study consists of two phases: 1. Physical comparisons and 2. Virtual comparisons. In Phase 1, each participant is asked to perform (10) comparisons (each consisting of 3 known test fires and 1 unknown) using their comparison microscope and current method of comparison. Half of the participants receive fired bullets and half receive fired cartridge cases.
In Phase 2 of the study, the same participants will be given a virtual test consisting of (10) virtual comparisons (each consisting of 3 knowns and 1 unknown) of either fired bullets or fired cartridge cases. Each participant will be given access to software from either Cadre (TopMatch), Leeds (Evofinder), or LeadsOnline/ Ultra FT (Quantum) to view and compare the images. Participants will receive instructions on how to use the software and will be able to ask questions as needed. Each test kit will consist of a combination of scans from the (3) instruments listed above. While each of the vendors utilizes X3P file format, there are di erences in the appearance and resolution of images obtained. While the evaluations of the virtual kits have not started yet, we do not anticipate seeing a lot of difficulties in comparing scans of cartridge cases from different acquisition systems. For bullet scans, we encountered a surprising variety in the scans between systems, some due to the nature of the system, some due to post processing routines