Image matching algorithms for breech face marks and firing pins in a database of spent cartridge cases of firearms

On the market several systems exist for collecting spent ammunition data for forensic investigation. These databases store images of cartridge cases and the marks on them. Image matching is used to create hit lists that show which marks on a cartridge case are most similar to another cartridge case. The research in this paper is focused on the different methods of feature selection and pattern recognition that can be used for optimizing the results of image matching.The images are acquired by side light images for the breech face marks and by ring light for the firing pin impression. For these images a standard way of digitizing the images used. For the side light images and ring light images this means that the user has to position the cartridge case in the same position according to a protocol. The positioning is important for the sidelight, since the image that is obtained of a striation mark depends heavily on the angle of incidence of the light. In practice, it appears that the user positions the cartridge case with +/-10 degrees accuracy.We tested our algorithms using 49 cartridge cases of 19 different firearms, where the examiner determined that they were shot with the same firearm. For testing, these images were mixed with a database consisting of approximately 4900 images that were available from the Drugfire database of different calibers.In cases where the registration and the light conditions among those matching pairs was good, a simple computation of the standard deviation of the subtracted gray levels, delivered the best-matched images. For images that were rotated and shifted, we have implemented a "brute force" way of registration. The images are translated and rotated until the minimum of the standard deviation of the difference is found. This method did not result in all relevant matches in the top position. This is caused by the effect that shadows and highlights are compared in intensity. Since the angle of incidence of the light will give a different intensity profile, this method is not optimal.For this reason a preprocessing of the images was required. It appeared that the third scale of the "à trous" wavelet transform gives the best results in combination with brute force. Matching the contents of the images is less sensitive to the variation of the lighting.The problem with the brute force method is however that the time for calculation for 49 cartridge cases to compare between them, takes over 1 month of computing time on a Pentium II-computer with 333MHz. For this reason a faster approach is implemented: correlation in log polar coordinates. This gave similar results as the brute force calculation, however it was computed in 24h for a complete database with 4900 images.A fast pre-selection method based on signatures is carried out that is based on the Kanade Lucas Tomasi (KLT) equation. The positions of the points computed with this method are compared. In this way, 11 of the 49 images were in the top position in combination with the third scale of the à trous equation. It depends however on the light conditions and the prominence of the marks if correct matches are found in the top ranked position. All images were retrieved in the top 5% of the database. This method takes only a few minutes for the complete database if, and can be optimized for comparison in seconds if the location of points are stored in files.For further improvement, it is useful to have the refinement in which the user selects the areas that are relevant on the cartridge case for their marks. This is necessary if this cartridge case is damaged and other marks that are not from the firearm appear on it.     

Influence of ballistic and autopsy parameters on the manner of death in case of long firearms fatalities

A retrospective study was carried out on 132 fatalities due to gunshot wounds secondary to long firearms. One group of suicide (n=72) and one group of homicide (n=60) were statistically compared regarding age and sex of the victim, number of shots, range of fire, direction of the projectile(s), anatomical distribution of entrance sites, weapon and ammunition types and the nature of eventual associated traumatic lesions. The frequency of suicide was higher when the victim's age increased. Females constituted about 43% of the homicide victims and about 8% of the suicide victims. 51.5% of the homicide victims and about 10% of the suicide victims had sustained more than one gunshot wound. Close range was respectively found in 53.5% of the homicide cases and in all suicide cases. Most of the suicide cases (85% of the cases) showed typical entrance sites. Entrance sites in the limbs and lateral or posterior wall of the chest were only encountered in homicide cases. Associated traumatic lesions were found in about 23% of the homicide cases and in 18% of the suicide cases. In case of suicidal gunshots to the left chest, both upwards and downwards directions, and also both right-to-left and left-to-right directions can occur. From 22 suicide cases showing entrance wound in the mouth, a downwards direction was found in only one. This study underlines the importance but also the limits of the autopsy findings (including direction of the projectile(s) related to the entrance site) for giving an indication of the manner of death (homicide vs. suicide).     

Echo correlation analysis and the acoustic evidence in the Kennedy assassination revisited.

A Dallas Police Department recording contemporaneous with the Kennedy assassination contains five impulsive sounds that have the acoustic waveform of Dealey Plaza gunfire. One of the sounds matches the echo pattern of a test shot fired from the Grassy Knoll. The shock wave precedence associated with this pattern is consistent with the muzzle velocity of a .30 calibre rifle. Criticism of the acoustic identifications on statistical grounds is based on erroneous assumptions concerning the assignment of values to the parameters that determine the probability that random noises could resemble gunshot patterns. A conservative estimate of the true value of the probability that the putative Grassy Knoll shot is attributable to random radio noise is no greater than 0.037. Alleged asynchroneity of the sounds with the time of the assassination stemmed from several incorrect assumptions. Whatever their origin, the gunshot-like sounds occur exactly synchronous with the time of the shooting.     

The evaluation of evidence in the forensic investigation of fire incidents (Part I): an approach using Bayesian networks

The forensic investigation of the origin and cause of a fire incident is a particularly demanding area of expertise. As the available evidence is often incomplete or vague, uncertainty is a key element. The present study is an attempt to approach this through the use of Bayesian networks, which have been found useful in assisting human reasoning in a variety of disciplines in which uncertainty plays a central role. The present paper describes the construction of a Bayesian network (BN) and its use for drawing inferences about propositions of interest, based upon a single, possibly non replicable item of evidence: detected residual quantities of a flammable liquid in fire debris.     

Event Studies and the Law: Part I: Technique and Corporate Litigation

Event studies are among the most successful uses of econometricsin policy analysis. By providing an anchor for measuring theimpact of events on investor wealth, the methodology offersa fruitful means for evaluating the welfare implications ofprivate and government actions. This article is the first ina set of two that review the use and impact of the event studymethodology in the legal domain. This article begins by brieflyreviewing the event study methodology and its strengths andlimitations for policy analysis. It then reviews in detail howevent studies have been used to evaluate the wealth effectsof corporate litigation: defendants experience economicallymeaningful and statistically significant wealth losses uponthe filing of the suit, whereas plaintiff firms experience nosignificant wealth effects upon filing a lawsuit. Also, thereis a significant wealth increase for defendant firms when theysettle a suit with another firm, in contrast to other typesof plaintiffs, and in contrast to the settling plaintiff firms.These findings suggest that, at a minimum, lawsuits are nota value-enhancing way for corporations to settle their disagreementswith other corporations. In addition, the market appears toimpose a higher sanction on firms than actual criminal sanctions,and reputational losses are of equal magnitude for civil finesas for criminal ones. The article concludes with some recommendationsfor researchers: the standards for conducting an event studyare well established; researchers can increase the power ofan event study by increasing the sample size, and by narrowingthe public announcement period to as short a time frame as possible.The companion article reviews the use of event studies in corporatelaw and regulation.     

Older and more recent evidence on racial discrimination in sentencing

Examination of previous studies of racial discrimination in sentencing indicates more widespread evidence of discrimination than allowed in three separate reviews by M. J. Hindelang [(1969).J. Crim. Law Criminal. Police Sci. 60: 306–313], J. Hagan [(1975). InThe Aldine Crime and Justice Annual, Aldine, Chicago], and G. Kleck [(1981).Am. Social. Rev. 46: 783-805]. It is not the case, as these reviewers suggest, that racial discrimination is a thing of the past, shown almost exclusively for capital offences from the American South, and often supported only because relevant legal variables were not controlled. In addition, analysis of recent (1977) data from a non-Southern state (Pennsylvania) covering noncapital offenses and including recommended controls shows that evidence of racial disparity in sentencing is revealed more clearly when separate analyses are conducted within levels of urbanization. The labeling perspective and conflict theory guide our interpretation.     

CONTU revisited: the case against copyright protection for computer programs in machine-readable form

Professor Samuelson casts a critical eye on the Final Report of the National Commission on New Technological Uses of Copyrighted Works (CONTU) which recommended that copyright protection be extended to machine-readable versions of computer programs. CONTU appears to have misunderstood computer technology and misinterpreted copyright tradition in two significant respects. The Commission failed to take into account the historical importance of disclosure of the contents of protected works as a fundamental goal of both the copyright and patent laws. It also erroneously opined that the utilitarian character of a work was no bar to its copyrightability when both the statute and the case law make clear that utilitarian works are not copyrightable. Since computer programs in machine-readable forms do not disclose their contents and are inherently utilitarian, copyright protection for them is inappropriate. Congress acted on CONTU's recommendation without understanding the significance of these conceptual flaws. Professor Samuelson recommends the creation of a new form of intellectual property law specifically designed for machine-readable programs.     

Worldwide policy trends in agricultural extension: Part I

Agricultural extension is one of the oldest and most important prototypes for technology-transfer organizations. The purpose of this paper is to help policymakers to keep track of how extension is developing in countries throughout the world. Such attention is especially warranted as extension has come under attack both in its identification with the public sector and in how that tie is expressed. Five fundamental models for organizing extension are outlined: farmingsystems research and extension, farming-information dissemination, training and visit, communications for technology transfer, and the cooperative-extension system of the U.S. Part I of this two-part paper outlines the major policy issues raised by these models and Part II (to be published in a later issue) will provide an in-depth discussion of a central issue underlying these models: the appropriate role of public- versus private-sector extension.     

Trajectory reconstructions. I: Trace evidence in flight

This paper reviews the use of trace evidence recovered from spent bullets in helping to establish trajectories. The use of information derived from such trace evidence combined with that from geometrical techniques of trajectory reconstruction and other data is discussed. Five cases are reviewed in which the analysis of trace evidential materials adhering to bullets was used to help reconstruct the event.     

The trust in Spanish and Italian private international law: Part I

Civil Law jurisdictions' recognition of trusts depends on theindividual conflict of law rules of each jurisdiction. The HagueConvention on the Recognition and Enforcement of Trusts intendsto bring a degree of certainty into how a foreign trust is received.However, the matter is complicated, in particular, as to thestatus granted in each jurisdiction to the convention. Thisarticle, based on a paper presented at the convention on CatalanCivil Law, ‘Los patrimonios fiduciarios y el trust’,held in Tarragona on 20 and 21 October 2005, examines the positionof trusts under the conflict of law rules in Italy and in Spainand the impact made on the recognition of trusts by the HagueConvention. This article appears in two parts; in this firstpart the position in Italy is examined and the second part concludeswith the position in Spain.     

New perspectives in the use of ink evidence in forensic science: Part III: Operational applications and evaluation

The research reported in this series of article aimed at (1) automating the search of questioned ink specimens in ink reference collections and (2) at evaluating the strength of ink evidence in a transparent and balanced manner. These aims require that ink samples are analysed in an accurate and reproducible way and that they are compared in an objective and automated way. This latter requirement is due to the large number of comparisons that are necessary in both scenarios. A research programme was designed to (a) develop a standard methodology for analysing ink samples in a reproducible way, (b) comparing automatically and objectively ink samples and (c) evaluate the proposed methodology in forensic contexts.This report focuses on the last of the three stages of the research programme. The calibration and acquisition process and the mathematical comparison algorithms were described in previous papers [C. Neumann, P. Margot, New perspectives in the use of ink evidence in forensic science—Part I: Development of a quality assurance process for forensic ink analysis by HPTLC, Forensic Sci. Int. 185 (2009) 29–37; C. Neumann, P. Margot, New perspectives in the use of ink evidence in forensic science—Part II: Development and testing of mathematical algorithms for the automatic comparison of ink samples analysed by HPTLC, Forensic Sci. Int. 185 (2009) 38–50].In this paper, the benefits and challenges of the proposed concepts are tested in two forensic contexts: (1) ink identification and (2) ink evidential value assessment. The results show that different algorithms are better suited for different tasks. This research shows that it is possible to build digital ink libraries using the most commonly used ink analytical technique, i.e. high-performance thin layer chromatography, despite its reputation of lacking reproducibility. More importantly, it is possible to assign evidential value to ink evidence in a transparent way using a probabilistic model. It is therefore possible to move away from the traditional subjective approach, which is entirely based on experts’ opinion, and which is usually not very informative.While there is room for the improvement, this report demonstrates the significant gains obtained over the traditional subjective approach for the search of ink specimens in ink databases, and the interpretation of their evidential value.     

Moral theories of torts: Their scope and limits: Part I

One approach to legal theory is to provide some sort of rational reconstruction of all or of a large body of the common law. For philosophers of law this has usually meant trying to rationalize a body of law under one or another principle of justice. This paper explores the efforts of the leading tort theorists to provide a moral basis — for the law of torts. The paper is divided into two parts. In the first part I consider and reject the view that tort law is best understood as falling either within the ambit of the principle of retributive justice, a comprehensive theory of moral responsibility, or an ideal of fairness inherent in the idea that one should impose on others only those risks others impose on one. The second part of the paper distinguishes among various conceptions of corrective or compensatory justice and considers arguments — including previous arguments by the author himself — to the effect that tort law is best understood as rooted in principles of corrective justice. This paper argues that although the use of principles of justice may render defensible many (but by no means all) of the claims to repair and to liability recognized in torts, it cannot explain why we have adopted a tort system as the approach to vindicating those claims. Some other principle — probably not one of justice — is needed to explain why it is that the victims claims to repair is satisfied by having his losses shifted to his injurer — rather than through some other means of doing so. The paper concludes that the law of torts cannot be understood — in the sense of being given a rational reconstruction — under any one principle of morality.