Version 1.1 / Date of Issue: 2.09.16 / Issuing Authority: Forensic Science Standards Board (FSSB)

OSAC RESEARCH NEEDS ASSESSMENT FORM

Title of research need: Resolution Requirements for 3D Virtual Comparison Microscopy

Keyword(s): virtual comparison microscopy (VCM), toolmarks, 3D

Submitting subcommittee(s): Firearm and Toolmarks Date Approved:

(If SAC review identifies additional subcommittees, add them to the box above.)

Background Information:

1. Description of research need:

Evaluation of instrument resolution required and/or recommended for virtual comparison microscopy and 

three dimensional toolmark comparisons. Assessment of sizes/scale of impressed and striated toolmarks 

utilized by examiners. 

2. Key bibliographic references relating to this research need:

Pierre Duez M.A.Sc., Todd Weller M.S., Marcus Brubaker Ph.D., Richard E. Hockensmith B.S. II, Ryan Lilien M.D., Ph.D., 

Development and Validation of a Virtual Examination Tool for Firearm Forensics, Journal of Forensic Sciences, 

Summer. 2018

Vorburger T.V., Rhee H.G., Renegar R.B., Song J, Zheng, X.A., “Comparison of Optical and Stylus Methods for 

Measurement of Rough Surfaces,” International Journal of Advanced Manufacturing Technology, 33(1):110-118, 2007

3a. In what ways would the research results improve current laboratory capabilities?

Significant research has been performed in the area of measuring and recording microscopic toolmarks. 

The measured toolmarks can be displayed “virtually”, i.e. on a computer screen, and compared using 

visualization software. High-resolution scans increase file size and acquisition time; low-resolution scans 

may result in the inability to reach source conclusions. Thus it would be useful to know: 1) what are the size 

of features used by examiners for comparison, 2) at what resolution do examiners lose the ability to discern 

the ground truth regarding source attribution, and 3) what resolution range (lateral and vertical) is 

recommended to digitize these features with sufficient fidelity. 

3b. In what ways would the research results improve understanding of the scientific basis for the 

subcommittee(s)?

As the Firearms and Toolmarks OSAC subcommittee writes standards on 3D instrumentation and VCM, 

having research that provides recommendations about resolution requirements would be helpful to both 

laboratories and manufacturers. 
Version 1.1 / Date of Issue: 2.09.16 / Issuing Authority: Forensic Science Standards Board (FSSB)

3c. In what ways would the research results improve services to the criminal justice system?

Standardize/provide best practice recommendations for VCM resolutions 

4. Status assessment (I, II, III, or IV): I Major gap in 

current 

knowledge

Minor gap in 

current 

knowledge

No or limited

current research 

is being conducted

I III

Existing current 

research is being 

conducted

II IV

This research need has been identified by one or more subcommittees of OSAC and is being provided as an 

informational resource to the community.

Approvals:

Subcommittee Approval date: 5/4/2018

(Approval is by majority vote of subcommittee. Once approved, forward to SAC.)

SAC

1. Does the SAC agree with the research need? Yes x No

2. Does the SAC agree with the status assessment? Yes x No

If no, what is the status assessment of the SAC:

Approval date: 5/4/2018

(Approval is by majority vote of SAC. Once approved, forward to NIST for posting.)