Semester

Spring

Date of Graduation

2011

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Forensic and Investigative Science

Committee Chair

Keith B. Morris

Committee Member

Suzanne Bell

Committee Member

Carl Necker

Abstract

When entering cartridge case exhibits into the Integrated Ballistics Identification System (IBIS®), examiners have the ability to manually manipulate three parameters: lighting intensity, ring selection and exhibit orientation. User guidelines for these settings are subjective, and the effect of examiner variation is largely unknown. If examiner variation negatively affects the returned correlation scores, the ability of the system to return true positives will be compromised. By entering cartridge cases into IBIS® 88 separate times, using 88 different combinations of parameter settings, the effect of these variables was determined. Analysis of variance testing revealed that no variable has a statistically significant effect on average true positive combined correlation scores or results list position. This did not change when the parameters were tested individually or in combination. Results indicate that examiner variability of cartridge case image acquisition has no effect on the outcome of IBIS®. The system’s matching algorithm is robust enough to handle exhibit entry and data collection without the intervention of human input. For this reason, acquisition could be completely automated, allowing examiners to focus on the decision making stage of cartridge case comparison.

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