title: Virtual tool mark generation for efficient striation analysis.
abstract: This study introduces a tool mark analysis approach based upon 3D scans of screwdriver tip and marked plate surfaces at the micrometer scale from an optical microscope. An open-source 3D graphics software package is utilized to simulate the marking process as the projection of the tip's geometry in the direction of tool travel. The edge of this projection becomes a virtual tool mark that is compared to cross-sections of the marked plate geometry using the statistical likelihood algorithm introduced by Chumbley et al. In a study with both sides of six screwdriver tips and 34 corresponding marks, the method distinguished known matches from known nonmatches with zero false-positive matches and two false-negative matches. For matches, it could predict the correct marking angle within ±5-10°. Individual comparisons could be made in seconds on a desktop computer, suggesting that the method could save time for examiners.
authors: Ames Laboratory, Iowa State University, 2096 Black Engineering, Ames, IA, 50011.
authors: Laura
authors: L
authors: Ekstrand
authors: Song
authors: S
authors: Zhang
authors: Taylor
authors: T
authors: Grieve
authors: L Scott
authors: LS
authors: Chumbley
authors: M James
authors: MJ
authors: Kreiser
keywords: computer simulation; forensic science; screwdriver; statistics; striae; tool mark comparison