Success Story: Advancing 3D Virtual Microscopy for Firearm Forensics

• NCJ Number: 252709
• Date Published: March 2019
• Length: 2 pages
• Grant Number(s): 2012-DN-BX-K058; 2013-R2-CX-K005; 2014-DN-BX-K012; 2015-DN-BX-K032; 2016-DN-BX-0182; 2017-IJ-CX-0024; 2018-DU-BX-0216
• Agencies: NIJ-Sponsored
• Publication Type: Research (Applied/Empirical); Report (Technical Assistance); Report (Study/Research); Report (Grant Sponsored); Program/Project Description
• Award: Applied Research, Development, and Method Validation for a Statistically Based Comparison of Tool Marks using GelSight-Based 3D Imaging and Novel Comparison Algorithms for Firearm Forensics; Applied Research and Development of a Three-dimensional Topography System for Imaging and Analysis of Striated and Impressed Tool Marks for Firearm Identification using GelSight; Applied Research and Development of a Three-dimensional Topography System for Firearm Identification using GelSight; Applied Research, Development, and Method Validation of Toolmark Imaging, Virtual Casing Comparison, and In-Lab Verification for Firearms Forensics; Advanced Scan Matching, Scalable Search, and Visualization Tools for the Analysis of 3D Scans of Cartridge Casings in Firearm Forensics; Evaluation of 3D Virtual Comparison Microscopy for Firearm Forensics within the Crime Lab; Firearm Forensics Black-Box Studies for Examiners and Algorithms using Measured 3D Surface Topographies

Annotation

This report describes the features and uses of the TopMatch-3D system for imaging firearms evidence.

Abstract

Developed by a team at Cadre Forensics, the TopMatch-3D system based the hardware on a patented imaging technology that uses a thin electrometric gel to produce accurate measurements of microscopic surface features. The Cadre team also developed specialized image matching algorithms that automatically detect and compare the 3 D impression features observed on a surface with one or many other possible matches. When used for virtual comparison microscopy (VCM), the system enables firearm examiners to accurately and efficiently reach conclusions without waiting for the physical exchange of evidence. Additional in=lab validation studies are being conducted to quantify the performance of the system under casework conditions. The TopMatch-3D desktop scanner is on the market and is used in casework by multiple agencies, including the FBI's Firearms/Toolmarks Unit. Based on forensic practitioner feedback, Cadre has developed an autosampler scanning tray that accepts up to 15 cartridge cases at a time. Collaborative testing services (CTS) has partnered with Cadre to offer a VCM proficiency test for training purposes. Cadre recently released the TopMatch-3D Portable Scanner, a hand-held system that can be used for triage or pre-screening at the crime scene to assist in selecting the highest priority evidence for further analysis.