85 research outputs found

    Assessing Forensic Ballistics Three-Dimensionally through Graphical Reconstruction and Immersive VR Observation

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    © The Author(s) 2022. This article is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.A crime scene can provide valuable evidence critical to explain reason and modality of the occurred crime, and it can also lead to the arrest of criminals. The type of evidence collected by crime scene investigators or by law enforcement may accordingly effective involved cases. Bullets and cartridge cases examination is of paramount importance in forensic science because they may contain traces of microscopic striations, impressions and markings, which are unique and reproducible as “ballistic fingerprints”. The analysis of bullets and cartridge cases is a complicated and challenging process, typically based on optical comparison, leading to the identification of the employed firearm. New methods have recently been proposed for more accurate comparisons, which rely on three-dimensionally reconstructed data. This paper aims at further advancing recent methods by introducing a novel immersive technique for ballistics comparison by means of Virtual Reality. Users can three-dimensionally examine the cartridge cases shapes through intuitive natural gestures, from any vantage viewpoint (including internal iper-magnified views), while having at their disposal sets of visual aids which could not be easily implemented in desktop-based applications. A user study was conducted to assess viability and performance of our solution, which involved fourteen individuals acquainted with the standard procedures used by law enforcement agencies. Results clearly indicated that our approach lead to faster adaptation of users to the UI/UX and more accurate and explainable ballistics examination results.Peer reviewe

    Objective analysis of toolmarks in forensics

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    Since the 1993 court case of Daubert v. Merrell Dow Pharmaceuticals, Inc. the subjective nature of toolmark comparison has been questioned by attorneys and law enforcement agencies alike. This has led to an increased drive to establish objective comparison techniques with known error rates, much like those that DNA analysis is able to provide. This push has created research in which the 3-D surface profile of two different marks are characterized and the marks\u27 cross-sections are run through a comparative statistical algorithm to acquire a value that is intended to indicate the likelihood of a match between the marks. The aforementioned algorithm has been developed and extensively tested through comparison of evenly striated marks made by screwdrivers. However, this algorithm has yet to be applied to quasi-striated marks such as those made by the shear edge of slip-joint pliers. The results of this algorithm\u27s application to the surface of copper wire will be presented. Objective mark comparison also extends to comparison of toolmarks made by firearms. In an effort to create objective comparisons, microstamping of firing pins and breech faces has been introduced. This process involves placing unique alphanumeric identifiers surrounded by a radial code on the surface of firing pins, which transfer to the cartridge\u27s primer upon firing. Three different guns equipped with microstamped firing pins were used to fire 3000 cartridges. These cartridges are evaluated based on the clarity of their alphanumeric transfers and the clarity of the radial code surrounding the alphanumerics

    Forensic comparison of fired cartridge cases: Feature-extraction methods for feature-based calculation of likelihood ratios

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    We describe and validate a feature-based system for calculation of likelihood ratios from 3D digital images of fired cartridge cases. The system includes a database of 3D digital images of the bases of 10 cartridges fired per firearm from approximately 300 firearms of the same class (semi-automatic pistols that fire 9 mm diameter centre-fire Luger-type ammunition, and that have hemispherical firing pins and parallel breech-face marks). The images were captured using Evofinder®, an imaging system that is commonly used by operational forensic laboratories. A key component of the research reported is the comparison of different feature-extraction methods. Feature sets compared include those previously proposed in the literature, plus Zernike-moment based features. Comparisons are also made of using feature sets extracted from the firing-pin impression, from the breech-face region, and from the whole region of interest (firing-pin impression + breech-face region + flowback if present). Likelihood ratios are calculated using a statistical modelling pipeline that is standard in forensic voice comparison. Validation is conducted and results are assessed using validation procedures and validation metrics and graphics that are standard in forensic voice comparison

    Evaluating the utilisation of Integrated Ballistic Identification System (IBIS) in the investigation of firearms-related crimes in Pretoria

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    The rise in firearms-related crimes which involve a repeated use of firearms by criminal syndicates in South Africa, has become a huge concern and has reached alarming levels. The aim of this research was to evaluate the role played by SAPS Forensic Science Laboratory in use of the integrated ballistic identification system (IBIS) in the investigation of firearms-related crimes, with the objectives to understand what is IBIS, and the purpose therefore to evaluate and understand the processes employed using IBIS in the investigation of firearms hence the following questions were answered: What is the meaning of IBIS and how is it used in the investigations of firearms? The researcher evaluated how forensic analysts are currently examining exhibits (firearms, cartridge cases and bullets) with the use of IBIS and highlighted the inefficiencies that hinder effective use of the IBIS system. A qualitative approach was adopted in conducting the study, where interviews, documents and personal experiences were used as data collection methods. The researcher made use of an empirical design, as the information available on the research topic was limited. The empirical design, together with a qualitative research approach, allowed for real-life observations. The researcher used purposive sampling to select ballistic experts with experience and knowledge of IBIS and firearms-related investigations. With limited time available for the research, purposive sampling is somewhat less costly, more readily accessible, more convenient and selects only those individuals that are relevant to research design. In terms of the use of IBIS in the investigation of firearms-related crimes, the research found that IBIS was not sufficiently utilised in the investigation of firearms-related crimes. Though useful and efficient when used effectively, there are inefficient processes impeding the use of the IBIS system to its full potential. Recommendations are that Forensic Science Laboratory (FSL) Ballistics Section management optimally utilise IBIS in the investigation of firearms-related crimes. This can be achieved through further training of the ballistic analysts and the development of new management procedures to be implemented specifically to govern the operation of the system.Police PracticeM.A. (Criminal Justice

    Recognition of Important Features on Weapon Shells

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    Text se zabývá automatickým rozpoznáváním a porovnáváním markantních rysů na nábojnicích, tak aby se zlepšila efektivita podobných manuálních balistických systémů. Práce reší problematiku programování aplikace pro automatické rozpoznávání a porovnávání markantních rysů na použitých nábojnicích.The text covers the automated recognition and comparison of features on used cartridge cases, in order to increase e ectivity of similar manual ballistic systems. The work is addresing the issue of programming the application for automated recognition and comparison of features on used cartridge cases.
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