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Advanced Scan Matching, Scalable Search, and Visualization Tools for the Analysis of 3D Scans of Cartridge Casings in Firearm Forensics

NCJ Number
Date Published
July 2018
25 pages
In this report, researchers who began development of a 3D surface topography imaging and analysis system for firearm forensics in 2013 describe methods and findings for the current project that extended their work and enabled continued adoption of 3D in the crime lab.

Specifically. the current project sought to improve the matching algorithm to enable recall for minimally marked cartridge cases; significantly increase the speed of a database search by developing a distributed computing version of the search method; and create and release free 3D viewer software for use by firearm and toolmark examiners. These three goals were completed successfully. Regarding the first objective, researchers determined that although it is impossible to achieve the same performance on minimally marked cartridge cases as with well-marked cartridge cases, they were able to recall approximately 25 percent of the minimally marked cartridge cases in the set. Regarding the second objective, the project developed and tested a scalable computing platform for remote search. The solution was implemented on the AWS platform and allows parallelization of data storage and search. Scalable solutions, such as the one developed in this project, will become increasingly important, given the size of 3D surface topography files, the increasing number of entries in scan databases, and the increasing sophistication of comparison algorithms. Regarding the third objective, the project continued to expand and support the only free X3P viewer for firearm forensics. Major sections of this report describe materials and methods used, as well as data results and analysis. 7 figures and 9 references

Date Published: July 1, 2018