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Optical Topography Increases Potential for Firearms Identification

NCJ Number
Date Published
May 2017
6 pages
Based on recent research funded by the National Institute of Justice, this article reports that in contrast to traditional approaches to the identification of ballistic markings, optical topography provides a three-dimensional view of the surface of a bullet or cartridge case at resolutions that can capture the full range of subclass and individual characteristics, and the implications of this finding are discussed.

Agencies have begun using this technology to develop searchable databases and to complement the use of the comparison microscope in making difficult comparisons. The detail in an optical topography image can supplement image data used in completed comparisons and clarify the basis on which an examiner has made a decision. Optical topography produces reference-collection searches that are more rapid and accurate than other methods. If an agency uses this technology with the Bureau of Alcohol, Tobacco, Firearms and Explosives' (ATF's) National Integrated Ballistic Information Network (NIBIB), it can also provide more interjurisdictional links with greater reliability. A version of the technology is being incorporated into new NIBIN workstations for use in database searching, which makes it a more powerful tool. Using optical-topography data greatly increases the chances that if a bullet or cartridge case fired from a particular gun has been entered into NIBIN, it will be near the top of the list in a comparison search. Also, with optical topography, examiners from two different labs should theoretically be able to examine evidence and research the same objective, quantitative conclusion, even if they are using different instruments. Implications of this technology for investigations by small and rural departments are also discussed in this article.

Date Published: May 1, 2017