Automatic Comparison and Evaluation of Impressions Left by a Firearm on Fired Cartridge Cases

Riva, Fabiano; Champod, Christophe

doi:10.1111/1556-4029.12382

Cited by 49 publications

(64 citation statements)

References 16 publications

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“…In the final step, we convert each similarity score into a statement of probability, specifically a “random match probability” given a known database. Both and propose methods for computing likelihood ratios, which are a ratio of the densities of similarity scores using nonmatch versus match distributions. In , a parametric distribution applicable to all guns is proposed, while proposes case‐specific distributions, determined empirically by conducting test fires for each make and model of gun.…”

Section: Methodsmentioning

confidence: 99%

A Fully Automatic Method for Comparing Cartridge Case Images,

Tai

Eddy

2017

Journal of Forensic Sciences

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When a gun is fired, it leaves marks on cartridge cases that are thought to be unique to the gun. In current practice, firearms examiners inspect cartridge cases for "sufficient agreement," in which case they conclude that they come from the same gun, testifying in courts as such. A 2016 President's Council of Advisors on Science and Technology report questioned the scientific validity of such analysis (President's Committee of Advisors on Science and Technology, Washington, DC, Executive Office of the President). One recommendation was to convert firearms analysis to an objective method. We propose a fully automated, open-source method for comparing breechface marks on cartridge cases using 2D optical images. We improve on existing methodology by automating the selection of marks, and removing the effects of circular symmetry. We propose an empirical computation of a "random match probability" given a known database, which can be used to quantify the weight of evidence. We demonstrate an improvement in accuracy on images from controlled test fires.

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Section: Methodsmentioning

confidence: 99%

A Fully Automatic Method for Comparing Cartridge Case Images,

Tai

Eddy

2017

Journal of Forensic Sciences

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“…Modern automated techniques using 3D images have also been proposed by Riva and Champod (2014). However, the authors focused on cartridge cases and not bullets.…”

Section: Figmentioning

confidence: 99%

Automatic matching of bullet land impressions

Hare¹,

Hofmann²,

Carriquiry³

2017

Ann. Appl. Stat.

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In 2009, the National Academy of Sciences published a report questioning the scientific validity of many forensic methods including firearm examination. Firearm examination is a forensic tool used to help the court determine whether two bullets were fired from the same gun barrel. During the firing process, rifling, manufacturing defects, and impurities in the barrel create striation marks on the bullet. Identifying these striation markings in an attempt to match two bullets is one of the primary goals of firearm examination. We propose an automated framework for the analysis of the 3D surface measurements of bullet land impressions which transcribes the individual characteristics into a set of features that quantify their similarities. This makes identification of matches easier and allows for a quantification of both matches and matchability of barrels. The automatic matching routine we propose manages to (a) correctly identify land impressions (the surface between two bullet groove impressions) with too much damage to be suitable for comparison, and (b) correctly identify all 10,384 land-to-land matches of the James Hamby study (Hamby, Brundage and Thorpe, 2009).

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“…This kind of comparison traditionally uses optical microscopes, but to complete comparisons beyond human capability, to properly deal with open cases , and to perform a less subjective approach , forensic laboratories worldwide are implementing electronic solutions. Many commercial systems are currently available to implement a ballistic database and to perform automated comparisons .…”

mentioning

confidence: 99%

Influence Factors Regarding the Effectiveness of Automated Ballistic Comparison on 0.38 Special Caliber Bullets and Cartridge Cases

Santos

Muterlle

2018

Journal of Forensic Sciences

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Factors influencing effectiveness of automated comparisons, test-fired bullets, and cartridge cases from 0.38 Special revolvers were logged into the Evofinder Ballistic ID System. Tests were performed as follows: First test correlated test-fires of the same type, second test compared different types of ammunition components, third test replicated the second test in a larger database, and fourth test replicated the third test with students having no previous firearm identification experience. System effectiveness with projectiles in the first test was 0.89. With cartridge cases, effectiveness was 0.79 with combined results, but analysis of separate results by breech face and firing pin revealed low effectiveness by breech face (0.40). In the second, third, and fourth tests, effectiveness with projectiles were 0.61, 0.51, and 0.44. In addition, these tests had effectiveness with cartridge cases equivalent to 0.55, 0.43, and 0.44. Results are useful to establish routine protocols, system improvements, or comparative assessment of other electronic systems.

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Automatic Comparison and Evaluation of Impressions Left by a Firearm on Fired Cartridge Cases

Cited by 49 publications

References 16 publications

A Fully Automatic Method for Comparing Cartridge Case Images,

A Fully Automatic Method for Comparing Cartridge Case Images,

Automatic matching of bullet land impressions

Influence Factors Regarding the Effectiveness of Automated Ballistic Comparison on 0.38 Special Caliber Bullets and Cartridge Cases

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