Determining the Effectiveness of Noncontact Three-Dimensional Surface Scanning for the Assessment of Open Injuries

Noncontact three-dimensional (3D) surface scanning methods are used within forensic medicine to record traumas and other related findings. A structured light scanning technique is one of these methods and the most suitable for the forensic field. An assessment of the efficiency of different structured light scanners with forensic injuries is essential to validate this technique for wound documentation. The purpose of this study was to evaluate the capability of the HP structured light scanner Pro S3 for digitizing open injuries having complicated areas and depths. Fifteen simulated injuries on mannequins were scanned and assessed. Comparisons between 3D and direct wound measurements were made. The results showed that the technique was able to create detailed 3D results of the extensive injuries. Statistical significance tests revealed no difference between the two measurement methods. Because the scanner is applicable for routine work, it should be considered to confirm the same results on real cadavers and actual wounds.     

Improved Area of Origin Estimation for Bloodstain Pattern Analysis Using 3D Scanning

An important component of crime scene reconstruction is bloodstain pattern analysis (BPA). Where BPA concerns impact patterns, estimating the area of origin is critical information for scene reconstruction. Traditionally, this is achieved by measuring individual bloodstains and performing trigonometric calculations; however, 3D scanning has been proposed as a viable alternative for overcoming logistical and practical concerns with the manual method. Therefore, this project aimed to establish whether the FARO Focus 3D scanner and FARO Zone 3D software can improve the accuracy of area of origin estimates relative to the manual method. We created a series of eight bloodstain impact patterns and performed paired analysis using the two methods to estimate areas of origin for each pattern. Our data suggested that FARO-derived estimates were generally more accurate than using the manual method. FARO-estimated heights of origin areas were generally closer to the true distance. Both methods underestimated the distance from the wall for most patterns originating 150mm or greater from the wall, but overestimated distances for patterns originating closer to the wall. The degree to which distances were underestimated increased significantly the further the blood source was from the wall and was greater for FARO-derived estimates. The results of this research contribute to the validation of these instruments for operational implementation for BPA and should be considered alongside the practical benefits of 3D scanning relative to manual methods. Further, 3D scanning can provide reliable BPA reconstruction documentation for technical review and court presentation.     

现场分析处理技术的研究与思考

随着科技的发展，三维信息、三维虚拟现实动画已经越来越多的出现在人们的视野中。国内一些公安机关已经将三维虚拟技术应用到犯罪现场数据采集中，为了减少三维采集数据处理的时间，提高应用数据的效率。本文将研究方向定位在研发一个集一维信息、二维信息、三维信息、漫游系统、三维仿真动画等功能于一身的三维制作平台，并探讨其在案件侦查中的运用。     

A Holistic Multi-Scale Approach to Using 3D Scanning Technology in Accident Reconstruction

Three-dimensional scanning and documentation methods are becoming increasingly employed by law enforcement personnel for crime scene and accident scene recording. Three-dimensional documentation of the victim's body in such cases is also increasingly used as the field of forensic radiology and imaging is expanding rapidly. These scanning technologies enable a more complete and detailed documentation than standard autopsy. This was used to examine a fatal pedestrian-vehicle collision where the pedestrian was killed by a van while crossing the road. Two competing scenarios were considered for the vehicle speed calculation: the pedestrian being projected forward by the impact or the pedestrian being carried on the vehicle's bonnet. In order to assist with this, the impact area of the accident vehicle was scanned using laser surface scanning, the victim was scanned using postmortem CT and micro-CT and the data sets were combined to virtually match features of the vehicle to injuries on the victim. Micro-CT revealed additional injuries not previously detected, lending support to the pedestrian-carry theory.     

Swedish crime scene technicians: facilitations,epistemic frictions and professionalization from the outside

ABSTRACT

This article investigates the role of crime scene technicians in the Swedish criminal justice system, and particularly how Swedish crime scene technicians not only examine crime scenes but also facilitate the criminal justice system’s joint production of forensic evidence. It proposes thinking about the criminal justice system as a conglomeration of epistemic cultures, that is, of communities with different ways of producing and understanding forensic evidence. Such a perspective makes it possible to understand interprofessional frictions as epistemic frictions as well as to draw attention to the facilitations, mediations and translations that crime scene technicians perform. This perspective also makes it possible to illuminate how the crime scene technicians’ professionalization – a professionalization from the outside – affects both their future crime scene work and their facilitations.     

犯罪现场层次论

犯罪现场层次是犯罪现场存在表现及其被侦查人员认知的程度。犯罪现场是由犯罪时间、犯罪空间、犯罪嫌疑人条件、犯罪痕迹物证、犯罪活动过程、犯罪心理、犯罪证据等各种层次构成的复合体。研究犯罪现场层次论也是研究犯罪现场构成要素的存在及其在不同层面的联系。犯罪现场层次也是研究和揭示犯罪现场存在的一种认知。研究犯罪现场层次问题,也可以使我们对犯罪现场状况及其勘查工作质量给以程度判定。     

The Reconstruction of the Dynamic of a Murder Using 3D Motion Capture and 3D Model Buildings: The Investigation of a Dubious Forensic Case

Photographic surveying is fundamental to crime scene investigation. It is performed using 2D images; however, this method is limited because it does not offer a detailed view. We present a 3D (three‐dimensional) experimental model that has clarified unsolved aspects of a homicide. A woman was found dead in her home. Considering the large number of injuries on the victim, signs of the use of two weapons, and the absence of traces of the killer/s, several hypotheses about the dynamics and the number of offenders were made. The forensic surveys suggested that a single offender had used two weapons at the same time, but this hypothesis was considered to be impossible by investigators. Our 3D model allowed us to experimentally reproduce the murder and compare various dynamics. The model was used as evidence in Court to prove the hypothesis of a single killer and demonstrate that no other people were involved.     

对“四战”背景下强化犯罪现场勘查工作的思考

“四战”对刑事技术和侦查工作提出了新的要求,现场勘查工作还存在如现场勘查不到位、现场勘查指挥不力、信息化手段运用不充分、侦查员与技术员缺乏沟通等诸多问题,强化现场勘查工作是适应“四战”需要。     

Forensic Terrestrial Photogrammetry from a Single Image

Abstract:  Forensic terrestrial photogrammetry is one of the most valuable and low-cost resources of spatial data available today. Due to the ephemeral crime scene characteristics, these photographs can often capture information that is never to be seen again. This paper presents a novelty approach for the documentation, analysis, and visualization of crime scenes for which only a single perspective image is available. The photogrammetric process consists of a few well-known steps in close-range photogrammetry: features extraction, vanishing points computation, camera self-calibration, 3D metric reconstruction, dimensional analysis, and interactive visualization. Likewise, the method incorporates a quality control of the different steps accomplished sequentially. As a result, several cases of study are presented in the experimental results section in order to test their viability. The full approach can be applied easily through the free software, sv3DVision, which has been evaluated by a number of police officers, forensic scientists, and forensic educators satisfactorily.     

犯罪现场新概念

犯罪现场的概念伴随犯罪的产生而产生，也伴随着犯罪的变化而变化，现实斗争呼唤对犯罪现场概念的进一步认识。比较国内外的探索轨迹不难看出，传统的犯罪现场概念背离了科学定义规范，使其外延既有扩大的一面,又有缩小的成分。科学而切合现实的概念应当这样表述犯罪现场是指发生和存在犯罪行为的地点和场所。     

现场勘查指挥中存在的问题及其对策探析

现场勘查工作对刑事案件的侦破起着十分重要的作用,随着法制化进程的不断推进,对现场勘查各环节的规范化要求日益提高。当前各级公安机关都十分重视犯罪现场勘查仪器、设备的投入,然而硬件的完善只能为做好犯罪现场勘查工作提供技术支持,因此加强对犯罪现场勘查的环节控制,提出有针对性的解决对策就显得十分重要。     

Geomatic techniques in forensic science: A review

The purpose of this review paper is to highlight various geomatic techniques that crime scene reconstructionists or forensic practitioners can use to document different kinds of scenes, highlighting the advantages, disadvantages, and when best to use each technology. This paper explores geomatic techniques such as a total station, photogrammetry, laser scanners and structured light scanners and how they can be used to reconstruct crime scenes. The goal of this paper is not to discredit manual methods, as they are long standing and reliable, but instead to shed light on alternative methods that may produce equally or more accurate results with a more visually appealing final product. It is important for law enforcement and forensic professionals to understand the advantages and disadvantages of each technique, knowing when certain techniques should be used (and when they should not), and being able to revert to traditional methods if required.     

犯罪现场生物检材的发现、提取策略

在改进现场生物检材的发现和提取技术的同时,也要进行理论创新和体系构建,才能够更好地指导实践。全局的观点、具体案件具体分析和犯罪现场重建对于现场勘查中有效地发现、提取和利用生物检材是十分重要的。     

Application of non-contact scanning to forensic podiatry: A feasibility study

Foot impression evidence recovered from crime scenes can be available in the form of barefoot prints, sock-clad footprints, or as impressions within footwear. In some cases, suspects leave their footwear at the scene of the crime, and the insoles from the footwear can be important in linking a person to the footwear. The application of 3D data-collecting technology is becoming more and more popular within forensic science and has been used to recover footwear impression evidence. The present study is a feasibility study to discover if 3D data capturing devices can be applied to insoles; to capture the footprint impression for measurement using the Gunn method (a method used in forensic podiatry casework). Three different methods of data capture were conducted; Adobe Photoshop, MeshLab, and calipers used directly on the insole. Paired t-tests and Intraclass Correlation Coefficient (ICC) were conducted for all three data capture methods. Seven measurements used in this study were significantly different across all three methods. ICC scores were moderate to excellent for the Photoshop method, poor to good for the 3D method, and moderate to excellent for the Direct method.     

浅议模拟画像在侦查中的应用

模拟画像是实现对犯罪嫌疑人相貌视觉形象刻画的技术手段。模拟画像应成为犯罪现场勘查工作的一项基本的规范性内容。模拟画像技术要求勘查现场的应解决的主要问题和勘查重点有:(一)寻找、发现目击犯罪嫌疑人的受害人和其他证人;(二)访问、记录目击者对犯罪嫌疑人的感知过程;(三)提取、记录目击者对犯罪嫌疑人体貌特征的记忆;(四)对目击者的调查访问要讲究技巧。模拟画像在侦查中运用应注意的问题:(一)相貌学知识非常重要;(二)必须注意目击者的个体差异对模拟画像的影响;(三)证人之间不要有互相影响的情况;(四)对重要目击者的保护;(五)必要时重新进行模拟画像;(六)划定侦查范围非常重要;(七)可以确定犯罪嫌疑人,不能否定犯罪嫌疑人。     

The Influence of New Technologies on the Visual Attention of CSIs Performing a Crime Scene Investigation

Currently, a series of promising new tools are under development that will enable crime scene investigators (CSIs) to analyze traces in situ during the crime scene investigation or enable them to detect blood and provide information on the age of blood. An experiment is conducted with thirty CSIs investigating a violent robbery at a mock crime scene to study the influence of such technologies on the perception and interpretation of traces during the first phase of the investigation. Results show that in their search for traces, CSIs are not directed by the availability of technologies, which is a reassuring finding. Qualitative findings suggest that CSIs are generally more focused on analyzing perpetrator traces than on reconstructing the event. A focus on perpetrator traces might become a risk when other crime‐related traces are overlooked, and when analyzed traces are in fact not crime‐related and in consequence lead to the identification of innocent suspects.     

Smartphone and Tablet Applications for Crime Scene Investigation: State of the Art,Typology, and Assessment Criteria

The use of applications on mobile devices is gradually becoming a new norm in everyday life, and crime scene investigation is unlikely to escape this reality. The article assesses the current state of research and practices by means of literature reviews, semistructured interviews, and a survey conducted among crime scene investigators from Canada and Switzerland. Attempts at finding a particular strategy to guide the development, usage, and evaluation of applications that can assist crime scene investigation prove to be rather challenging. Therefore, the article proposes a typology for these applications, as well as criteria for evaluating their relevance, reliability, and answer to operational requirements. The study of five applications illustrates the evaluation process. Far away from the revolution announced by some stakeholders, it is required to pursue scientific and pragmatic research to set the theoretical foundations that will allow a significant contribution of applications to crime scene investigation.     

犯罪现场勘查存在的问题及其对策

通过现场勘查,就是要查清事件的性质,即研究和了解犯罪分子作案情况、作案动机和手段;研究和了解犯罪分子本人的特点和特征;发现和提取犯罪分子作案遗留的痕迹、物证;为侦查破案提供各方面的犯罪信息。侦查人员依靠这些犯罪信息,“再现犯罪”,确定侦查范围,制定侦查计划,采取侦查措施,进行侦查破案。     

An evaluation of measurement uncertainty of trajectory angles using a 3D laser scanner

Measuring trajectory angles of bullet defects at a crime scene is an important part of crime scene investigation as these angles can be used for shooting incident reconstructions. The Washington State Patrol Crime Scene Response Team (WSP CSRT) had a desire to report and use measured trajectory angles. To report quantitative measurements, a statement of uncertainty for the measurement must also be reported due to an accreditation requirement through the ANSI National Accreditation Board (ANAB), through which the WSP CSRT is accredited. This evaluation examined the measurement uncertainty of the 3D laser scanning method that the WSP CSRT utilizes for measuring the vertical and azimuth angles from trajectory rods fitted to bullet defects. Three studies were performed which examined the variation of vertical and azimuth angle measurements from trajectory rods on flat surfaces, the variation of azimuth angle measurements from a trajectory rod on a curved surface, and a traceability study with known vertical and azimuth angle measurements. Seven common substrates were selected as target materials and were shot with 9 mm Luger and 0.45 Auto caliber bullets. A vehicle with one bullet defect was utilized for the curved surface study. The WSP's current fleet of Trimble X7 3D laser scanners, the WSP Criminal Investigation Division (CID) Detectives who operate these scanners, and the Forensic Scientists responsible for trajectory rod placement and angle measurements were utilized. An overall measurement uncertainty of +/− 2.6 degrees at an approximate 95% confidence interval was determined for all trajectory angles measured from trajectory rods.