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Angular Determination of Toolmarks Using a Computer-Generated Virtual Tool

NCJ Number
Journal of Forensic Sciences Volume: 60 Issue: 4 Dated: July 2015 Pages: 878-884
Date Published
7 pages

A blind study was conducted to determine whether virtual toolmarks created using a computer could be used to identify and characterize angle of incidence of physical tool marks.


Six sequentially manufactured screwdriver tips and one random screwdriver were used to create toolmarks at various angles. An apparatus controlled tool angle. Resultant toolmarks were randomly coded and sent to the researchers, who scanned both tips and toolmarks using an optical profilometer to obtain 3D topography data. Developed software was used to create virtual marks based on the tool topography data. Virtual marks generated at angles from 30 to 85 degrees (5-degree increments) were compared to physical toolmarks using a statistical algorithm. Twenty of twenty toolmarks were correctly identified by the algorithm. On average, the algorithm misidentified the correct angle of incidence by -6.12 degrees. This study presents the results, their significance, and offers reasons for the average angular misidentification. (Publisher abstract modified)

Date Published: January 1, 2015