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Objective Comparison of Marks from Slip-Joint Pliers

NCJ Number
AFTE Journal Volume: 46 Issue: 2 Dated: Spring 2014
Date Published
0 pages

This article reports experimental results from a statistical analysis algorithm for objectively comparing toolmarks using data files obtained using optical profilometry data.


The algorithm employed has successfully been used to compare striated marks produced by screwdrivers. In this study, quasi-striated marks produced by the cutting surfaces of slip-joint pliers were examined. Marks were made by cutting both copper and lead wire. Data files were obtained using an optical profilometer that uses focus variation to determine surface roughness. Early efforts using the comparative algorithm yielded inconclusive results when the comparison parameters used were the same as those employed successfully for screw-driver marks. Further experiments showed that the algorithm could successfully be used to separate known matches from non-matches by changing the comparison parameters. Results are presented from the analysis of the copper wires (publisher abstract modified)

Date Published: January 1, 2014