Applications of Surface Metrology in Toolmark Identification

Published

January 8, 2014

Author(s)

Xiaoyu Alan Zheng, Johannes A. Soons, Theodore V. Vorburger, Jun-Feng Song, Thomas Brian Renegar, Robert M. Thompson

Abstract

Surface metrology is commonly used to characterize functional engineering surfaces. The technologies developed offer opportunities to improve forensic toolmark identification. In 2009, a report by the National Academies called into question, amongst others, the objectivity of visual toolmark identification by firearms examiners. The National Academies recommended development of objective toolmark identification criteria and characterization of error rates. The National Institute of Standards and Technology (NIST) uses its experience in surface metrology to develop objective identification criteria, measurement methods, and reference artefacts. Objectivity is improved through measurement of areal surface topography and application of unambiguous surface similarity metrics, such as the maximum value (ACCFMAX) of the areal cross correlation function. Case studies were performed on consecutively manufactured tools, such as gun barrels and breechfaces, to demonstrate that even in this worst case scenario, all the tested tools imparted unique surface topographies that were identifiable. These studies provide scientific support for toolmark evidence admissibility in criminal court cases.

Citation

Journal of Physics: Conference Series

Volume

2

Issue

1

Pub Type

Journals

Download Paper

https://doi.org/10.1088/2051-672X/2/1/014012

Local Download

Keywords

Striated Toolmarks, Impression Toolmarks, Areal Cross Correlation Function

Citation

, X. , Soons, J. , Vorburger, T. , Song, J. , , T. and Thompson, R. (2014), Applications of Surface Metrology in Toolmark Identification, Journal of Physics: Conference Series, [online], https://doi.org/10.1088/2051-672X/2/1/014012, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=913337 (Accessed December 3, 2024)