Manipulative Virtual Tools for Tool Mark Characterization

• NCJ Number: 241443
• Author(s): S. Zhang; L. S. Chumbley
• Date Published: January 2012
• Length: 50 pages
• Publication Series: NIJ Research Report
• Grant Number(s): 2009-DN-R-119
• Agencies: NIJ-Sponsored
• Publication Type: Report (Grant Sponsored)

Annotation

This final NIJ (National Institute of Justice) report presents the results of a study that developed manipulative virtual tools for use in characterizing tool marked surfaces.

Abstract

Preliminary findings from the study on the development of manipulative virtual tools for use in characterizing tool marked surfaces include the following: the method developed in the study was able to distinguish between matches and non-matches in a majority of the scans, with only a few false negatives being reported; the method was also able to generally distinguish between marks made at high and low angles; and the angle on the real mark predicted by the virtual mark could often achieved to within 5 degrees of the actual angle. The primary purpose for the development of the virtual tools is to improve the scientific basis for toolmark identifications. In the study, a 3-dimensional computer simulation of a tool tip was created and used to make "virtual toolmarks," allowing for the force, twist of the tool, and angle of attack of the tool tip to be varied. These toolmarks were manipulated to produce a range of markings, allowing examiners to obtain the best possible match to the actual tool to be found. The findings from the study indicate that in the right conditions, the virtual tool developed in this study can be made to generate 'virtual marks' for quantitative and objective toolmark characterization. Figures and references