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

© 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

Surface and topography metrology in firearm evidence identification and engineering surface quality control

This thesis is a topical review on the application of Surface and Topography Metrology in Firearm Evidence Identification and Engineering Surface Quality Control. It summarizes my research work at the National Institute of Standards and Technology (NIST) from 1987 to present, where I’m a Project Lead for the Forensic Topography and Surface Metrology since 1997. I started my research in surface metrology since 1982 -- after my MS study at the Harbin Institute of Technology (HIT, Harbin, China) from 1978 to 1981. In 1985, I designed, manufactured and patented the Precision Random Profile Roughness Specimens in Beijing aimed to provide a reference standard for quality control of smooth engineering surfaces [1]. These specimens were manufactured with Ra values ranging from 0.015 μm to 0.1 μm -- less than 1/10 of the similar specimens developed by PTB (Physikalisch-Technische Bundesanstalt) in Germany. These specimens were successfully used by U.S. manufacturers for measurement unification and quality control of smooth engineering surfaces, and were included in ASME B46 surface standard in 1995. Microform metrology is a subfield of surface metrology that involves surface measurements of complex geometry features on the micrometer scale. In 1995, I led a team at NIST which established a Microform Calibration System with the lowest calibration uncertainty in the world for calibration of Rockwell hardness (HR) diamond indenters. Based on the precision calibration of HR indenters and the control of other influencing quantities, I proposed a “Metrological Approach” to unifying international HRC scales with metrological traceability. I led an international HRC comparison among five National Metrological Institutes (NMIs). The comparison results strongly supported the proposed Metrological Approach. I drafted a joint paper for five NMIs entitled “Establishing a worldwide unified Rockwell hardness scale with metrological traceability” which was published at the Metrologia 34, 1997 in Paris [4]. Surface and topography metrology provides strong support to firearm evidence identifications. Based on my experience in developing surface standards, measurement systems, uncertainty and traceability procedures, I led a research team which developed the NIST Standard II Reference Material (SRM) Bullets and Cartridge Cases, and the NIST 2D/3D Topography Measurement System [5]. We formulated a National Traceability and Quality System using the SRM Bullets and Cartridge Cases to support ballistics identifications within the National Integrated Ballistics Information Network (NIBIN) in the United States [6]. I have recently invented a Congruent Match Cells (CMC) method for accurate ballistics identification and error rate estimation [7], which can serve as a statistical foundation for estimating error rates in firearm evidence identifications, thus emulating methods used for forensic identification of DNA evidences [8]

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

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

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

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

A critical review of the current state of forensic science knowledge and its integration in legal systems

Forensic science has a significant historical and contemporary relationship with the criminal justice system. It is a relationship between two disciplines whose origins stem from different backgrounds. It is trite that effective communication assist in resolving underlying problems in any given context. However, a lack of communication continues to characterise the intersection between law and science. As recently as 2019, a six-part symposium on the use of forensic science in the criminal justice system again posed the question on how the justice system could ensure the reliability of forensic science evidence presented during trials. As the law demands finality, science is always evolving and can never be considered finite or final. Legal systems do not always adapt to the nature of scientific knowledge, and are not willing to abandon finality when that scientific knowledge shifts. Advocacy plays an important role in the promotion of forensic science, particularly advocacy to the broader scientific community for financial support, much needed research and more testing. However, despite its important function, advocacy should not be conflated with science. The foundation of advocacy is a cause; whereas the foundation of science is fact. The objective of this research was to conduct a qualitative literature review of the field of forensic science; to identify gaps in the knowledge of forensic science and its integration in the criminal justice system. The literature review will provide researchers within the field of forensic science with suggested research topics requiring further examination and research. To achieve its objective, the study critically analysed the historical development of, and evaluated the use of forensic science evidence in legal systems generally, including its role regarding the admissibility or inadmissibility of the evidence in the courtroom. In conclusion, it was determined that the breadth of forensic scientific knowledge is comprehensive but scattered. The foundational underpinning of the four disciplines, discussed in this dissertation, has been put to the legal test on countless occasions. Some gaps still remain that require further research in order to strengthen the foundation of the disciplines. Human influence will always be present in examinations and interpretations and will lean towards subjective decision making.JurisprudenceD. Phil

The Gun Subsidy

Despite thousands of gun deaths annually, the United States has failed to reach consensus on any means of addressing the public health crisis that is gun violence. The issue has become politically polarized, constitutionalized, and an object of pessimism and despair. We propose a regulatory system in which gun manufacturers would be strictly liable to a federal fund for deaths caused by their guns, paired with a subsidy that will serve to ensure the availability of guns sufficient to meet the rights the Supreme Court has found in the Second Amendment. While strict liability of this kind can indeed serve its traditional purposes of spreading costs and incentivizing better designs and processes, our primary goal is to alter the political economy around the issue of gun violence more generally. If manufacturers bear an increasing share of the costs created by their products, they will endeavor not only to produce products and advertise them in ways likely to reduce those costs but also to advocate for regulations that may do the same. While our proposal may not depolarize the issue entirely, it at least attempts to focus the minds and experience of those who know guns best on effective means of reducing guns’ social costs

Models and Analysis of Vocal Emissions for Biomedical Applications

The MAVEBA Workshop proceedings, held on a biannual basis, collect the scientific papers presented both as oral and poster contributions, during the conference. The main subjects are: development of theoretical and mechanical models as an aid to the study of main phonatory dysfunctions, as well as the biomedical engineering methods for the analysis of voice signals and images, as a support to clinical diagnosis and classification of vocal pathologies

Databook for human factors engineers. Volume 2 - Common formulas, metrics, definitions

Human factors engineering manual including mathematical formulas, nomographs, conversion tables, units of measurement, and nomenclature