道路交通事故速度重建技术现状

事故车辆行驶速度是道路交通事故调查的重要内容,也是公安交通管理部门进行事故认定,法院进行司法审判的关键技术依据。目前事故车辆行驶速度调查的主要途径是办案单位委托具有专业技术能力的司法鉴定机构进行速度重建,使用的方法主要有基于事故形态的速度重建、基于模拟软件的速度重建、基于车载记录数据的速度重建和基于视频图像的速度重建。通过从速度重建的技术发展、执业类别和能力验证等方面介绍了我国道路交通事故速度重建技术的发展现状。     

Relative effects of posture and activity on human height estimation from surveillance footage

Height estimations based on security camera footage are often requested by law enforcement authorities. While valid and reliable techniques have been established to determine vertical distances from video frames, there is a discrepancy between a person's true static height and their height as measured when assuming different postures or when in motion (e.g., walking). The aim of the research presented in this report was to accurately record the height of subjects as they performed a variety of activities typically observed in security camera footage and compare results to height recorded using a standard height measuring device. Forty-six able bodied adults participated in this study and were recorded using a 3D motion analysis system while performing eight different tasks. Height measurements captured using the 3D motion analysis system were compared to static height measurements in order to determine relative differences. It is anticipated that results presented in this report can be used by forensic image analysis experts as a basis for correcting height estimations of people captured on surveillance footage.     

基于3D激光扫描、多刚体重建和遗传算法优化的车-人碰撞事故再现模拟与损伤分析

目的利用3D激光扫描技术,结合多刚体动力学和遗传算法优化对一起汽车与自行车及其骑车人碰撞的交通事故进行再现模拟与损伤分析,为法医学死因鉴定提供生物力学依据。方法利用3D激光扫描技术对肇事汽车进行测量,根据测量数据建立人-自行车-汽车多刚体模型,并设置优化变量的取值范围,利用多目标遗传算法,带精英策略的快速非支配排序遗传算法求最优近似解,并与事故现场附近监控视频记录进行比较。结果事故车辆激光扫描重建结果良好,通过遗传算法优化收敛所获得的最优近似解中的假人、自行车、汽车的动力学行为与监控视频中所记录的三者动力学行为相符合,假人的损伤参数也与事故中骑车人的损伤情况及部位相一致。结论利用3D激光扫描技术,结合多刚体动力学和遗传算法优化可以对人-自行车-汽车碰撞前的运动状态、碰撞致伤过程进行重建,并对受害者的损伤进行力学分析,在交通事故受害人致伤方式鉴定及死因分析中具有应用价值。     

视频方法鉴定车速的准确性研究

目的通过实验研究用视频方法鉴定车速结果的准确性及其影响因素。方法在选定的实验场地上,让实验车辆以一定速度匀速通过一段距离,使用高空、垂直、斜角和车载四个位置的摄像机同时录制,将车速计算结果进行比较。结果理论和实验数据分析表明,误差的大小主要取决于:车速和帧速率,车体上参考点和路上参考点的对齐效果,还有行车距离的大小和播放器屏幕的大小等。结论用视频方法进行车速鉴定,相对于传统的用力学公式进行计算,其准确性和可信度较好;一般条件下,误差可在5%~10%之间估算;夜晚条件下,可在车灯的轮廓线上选择车体上参考点,炫目情况除外。     

基于视频的车速鉴定方法

视频监控设备的广泛应用为各类案件的侦破及取证提供了重要线索。利用高质量视频图像进行近景摄影测量、运动物体识别及跟踪的方法和技术已经较为成熟,但利用广角、低像素的视频监控录像定量描述车辆行驶速度的技术研究尚未开展。针对交通事故技术鉴定的实际需求,根据速度的一般计算方法和计算机视觉的基本原理,提出可以应用目前广泛使用的公共视频监控设备所拍摄的录像进行车辆速度计算的方法。     

The body-worn camera perspective bias

Objectives

Footage from body-worn cameras (BWCs) is sometimes used to assess the quality of police interventions. This study investigates whether there is a “body-worn camera perspective bias,” in which the point of view provided by the footage influences perception of an intervention.

Methods

Participants with different backgrounds (undergraduate students and police candidates) were randomly allocated to a group that looked at one of two videos showing a fictional police intervention during which lethal force was used against a subject; both videos showed exactly the same intervention, but one had been filmed with a BWC and the other with a surveillance camera installed in a top corner of the room. Participants were then asked to rate the appropriateness of the intervention.

Results

No camera perspective bias was found among university respondents. However a significant camera perspective bias was found among police candidates: respondents’ opinions on the appropriateness of the intervention were significantly different when the film was from the body-worn camera than when it was seen from the surveillance camera. This result may be explained by the finding that viewers of the BWC footage reported that the subject was further from the officer.

Conclusions

Results suggest that the more training individuals have in analyzing police interventions, the more affected they will be by the camera perspective in these interventions. One implication of these results is that the perspective of people assigned and trained to evaluate the appropriateness of an intervention (e.g., members of a committee monitoring police misconduct) might be biased if only video footage from a BWC is presented.

     

The forensic investigation of vehicle–pedestrian collisions: A review

Rapid urbanisation, a steady increase in the number of vehicles, speeding, negligence in road safety, and other factors have led to the inevitable worldwide growth of road traffic accidents involving pedestrians. According to the ‘Global Status Report on Road Safety’ released by the World Health Organization, road traffic collisions are one of the leading causes of death for people of all ages, with approximately 1.35 million road fatality deaths occurring globally each year. Figures from the report also highlight that a large part of road deaths involves pedestrians as the most vulnerable road users. Therefore, forensic examination of vehicle–pedestrian collisions has become increasingly important in the detection, investigation and reduction of road casualties and permanent development of this discipline is urgently needed. Thus, this article aims to review the capability and effectiveness of forensic examination in tackling road fatalities and explores the most important aspects of this discipline, such as nature of a vehicle–pedestrian collision, common issues resolved by this type of examination and typical physical evidence used in the reconstruction of vehicle–pedestrian collisions. Moreover, the paper outlines the latest advances and approaches in the field.     

基于单车事故车速鉴定的取证技术

车速鉴定正成为道路交通事故司法鉴定的重要项目。单车事故由于其特殊性往往简单化处理。单车事故主要类型包括碰撞护栏、侧翻与坠崖等。单车事故车速鉴定原理主要是基于能量守恒定律。在分析三类事故常用鉴定计算公式基础上,对其取证要点进行了探究,包括护栏变形、车辆变形、圆周运动半径、坠车飞行距离等测量。并指出其他事故现场痕迹物证要素的测量对于车速鉴定可以起到辅助佐证的作用。     

多层螺旋CT在交通事故损伤生物力学分析中的应用

目的探讨多层螺旋CT(multi-slice computed tomography,MSCT)及三维重建技术在交通事故损伤生物力学分析方面的应用价值。方法以真实案例为基础,通过MSCT扫描获得尸体断层影像,进行三维图像重建,结合尸体解剖、车辆勘验等结果综合分析交通事故撞击、碾压和挤压等行为方式中的生物力学过程,并与尸体解剖结果进行对比。结果 MSCT和三维重建获得了不同受力部位骨折的位置、骨折线走向以及骨内碎裂状况等原位特征,其对于骨折的精细还原优于尸体解剖。结论 MSCT和三维重建技术在原位特征的再现、图像的易操作性以及证据的保全等方面凸显优势,可对道路交通事故损伤生物力学分析起补充和引导作用。     

Application of 3-D computer graphics for facial reconstruction and comparison with sculpting techniques

Facial reconstruction has until now been carried out by the sculpting technique. This method involves building a face with clay or other suitable material on to a skull or its cast, taking into account appropriate facial thickness measurements together with information provided by anthropologists such as approximate age, sex, race and other individual idiosyncrasies. A method for facial reconstruction is presented using 3-D computer graphics and is compared with the manual technique. The computer method involves initially digitising a skull using a laser scanner and video camera interfaced to a computer. A face, from a data bank which has previously digitised facial surfaces, is then placed over the skull in the form of a mask and the skin thickness is altered to conform with the underlying skull. The advantage of the computer method is its speed and flexibility. We have shown that the computer method for reconstructing a face is feasible and furthermore has the advantage over the manual technique of speed and flexibility. Nevertheless, the technique is far from perfect. Further facial thickness data needs collecting and the method requires evaluation using both known control skulls and later unknown remains.     

Pre-set estimation-based in-silico silhouette-based methodology for improving the robustness to viewing direction difference for assisting forensic gait analysis

Forensic gait analysis is used to visually and quantitatively analyze information regarding the appearance and style of walking that can be presented as evidence in the court. The demand for analyzing CCTV pedestrian footage in video surveillance has been increasing. The dependence of the accuracy of semiautomatic silhouette-based analysis, often used in forensic science, on the differences in the viewing directions is a very challenging issue that is yet to be resolved for real case applications. Currently, the different viewing directions used in comparison footage significantly decrease the accuracy of same person analysis when using the silhouette-based method, often used in the Japanese forensic science domain. A calibration-based method was previously prosed to resolve this problem, but it requires performing an elaborate measurement procedure at the camera installation site for an accurate analysis. In this study, we propose a novel in-silico silhouette-based analysis method that significantly expands the number of viewing direction pre-set settings to 900 from the 24 used in the previous method. Several software tools have been developed to ensure that all the procedures can be executed on a computer. The experimental results confirm that the accuracy of the proposed method is comparable to that of the calibration-based method. Furthermore, the practical comparison results from actual consultation confirmed the effectiveness of the proposed method under existing viewing direction differences. We therefore anticipate that the proposed method will be beneficial for improving the analysis accuracy in real cases and therefore serve as a substitute of the previous method.     

交通事故中车辆安全技术状况检验及典型案例车速计算

目的 针对导致交通事故的各种原因就车辆因素进行了较详细的分析.方法 对进行车辆技术状况检验的着手方面、要点做了相关分析并结合相关实例进行举例分析,对造成事故中的关键因素车速的计算及计算方法做了简要讨论.结果 总结了进行整车配置、制动系统、转向系统、汽车灯光与信号系统与轮胎检验时需注意的要点.根据车速计算方法,得出一起追尾事故中某货车在事发时未达到高速公路最低限速的鉴定结论.结论 进行车辆安全技术状况检验时,需注意相关要点,以尽量避免道路交通事故的发生.     

电动两轮车侧翻倒地滑动摩擦系数实验研究

目的两轮车侧翻倒地后的滑行摩擦系数是利用两轮车碰撞后倒地滑行距离进行速度计算的关键参数,论文通过试验研究提出用于道路交通事故速度计算的电动两轮车侧翻倒地滑动摩擦系数。方法在综合分析电动两轮车侧倒滑行摩擦系数影响因素的基础上,利用正交试验设计摩擦系数实验方案,并采用实车牵引的方法,在不同速度条件下,分别在干燥、潮湿的沥青混凝土路面及水泥混凝土路面上进行实验。结果实验所得数据显示,电动两轮车侧翻倒地滑动摩擦系数的范围为0.40～0.60。结论通过对所得数据进行处理,提出适用于电动两轮车交通事故再现的摩擦系数范围。     

Determination of average vehicle speed utilizing reverse projection

Reverse projection photogrammetry has long been used to estimate the height of an individual in forensic video examinations. A natural extrapolation would be to apply the same technique on a video to estimate the speed of an object by determining the distance traveled between two points over a set amount of time. To test this theory, five digital video recorders (DVRs) were connected to a single fixed camera to record a vehicle traveling down a track. The vehicle's speed was measured through Doppler radar by a trained operator and the speedometer of the vehicle was also recorded with a video camera. The recorded video was examined and the frames that best depict the beginning and end of the vehicles course were selected. Two reverse projection photogrammetric examinations were performed on the selected frames to establish the position of the vehicle. The distance between the two points was measured, and the time elapsed between the two points was examined. The outcome provided an accurate speed result with a standard degree of uncertainty. This study proves the feasibility of using video data and reverse projection photogrammetry to determine the speed of a vehicle with a limited set of variables. Further research is needed to determine how additional variables would impact the standard degree of uncertainty.     

IoT forensics: Exploiting log records from the DAHUA technology CCTV systems

CCTV surveillance systems are ubiquitous IoT appliances. Their forensic examination has proven critical for investigating crimes. DAHUA Technology is a well-known manufacturer of such products. Despite its global market share, research regarding digital forensics of DAHUA Technology CCTV systems is scarce and currently limited to extracting their video footage, overlooking the potential presence of valuable artifacts within their log records. These pieces of evidence remain unexploited by major commercial forensic software, yet they can hide vital information for an investigation. For instance, these log records document user actions, such as formatting the CCTV system's hard drive or disabling camera recording. This information can assist in attributing nefarious actions to specific users and hence can be invaluable for understanding the sequence of events related to incidents. Therefore, in this paper, several DAHUA Technology CCTV systems are thoroughly analyzed for these unexplored pieces of evidence, and their forensic value is presented.     

The influence of vehicle model and colour on assessments of speed and culpability: the case for (and against) Computer Generated Exhibits (CGE)

Computer Generated Exhibits (CGE) are frequently deployed in legal contexts under the rubric of demonstrative evidence, i.e. to facilitate juror comprehension. However, a number of legal and academic commentators have suggested that the nature of the computerised moving image could exert undue prejudice on decision makers, e.g. judge and/or jury. The current study aimed to assess the manipulation of vehicle characteristics (make and colour) when a road traffic accident was presented in the format of a computer generated animation (CGA). In experiment 1, two groups of subjects watched two different makes of car, a Range Rover Sport and a Volkswagen Touran in a black-and-white format; no significant differences emerged over vehicle model with regards to vehicle speed or overall responsibility for the accident. Experiment 2 presented the same vehicles to four groups of participants in full colour, with the cars in contrasting red or beige; significant differences emerged with regards to culpability for vehicle make only. The findings could have implications for the format and style of CGE used in legal settings.     

交通事故归责原则与损害赔偿理论研究

《道路交通事故处理办法》与《中华人民共和国民法通则》关于道路交通事故的归则原则完全不同 ,这导致了交通事故损害赔偿的不同。分析比较了各主要国家对交通事故的归责原则 ,并且从法学理论上对之进行研究。认为汽车与非机动车、行人发生的交通事故 ,应采取无过错责任原则 ,才更能体现法的公平与正义     

Comparison of the Performance of Two Methods for Height Estimation

Abstract: In the case study, two methods of performing body height measurements in images are compared based on projective geometry and 3D modeling of the crime scene. Accuracy and stability of height estimations are tested using reconstruction images of test persons of known height. Given unchanged camera settings, predictions of both methods are accurate. However, as the camera had been moved in the case, new vanishing points and camera matches had to be created for the reconstruction images. 3D modeling still yielded accurate and stable estimations. Projective geometry produced incorrect predictions for test persons and unstable intervals for questioned persons. The latter is probably caused by the straight lines in the field of view being hard to discern. With the quality of material presented, which is representative for our case practice, using vanishing points may thus yield unstable results. The results underline the importance of performing validation experiments in casework.     

车外人员与汽车碰撞事故现场痕迹特点分析

道路交通事故的发生是人、车、道路等因素综合作用的结果，碰撞过程中。三者之间在极短的时间内发生了强烈的相互作用，如制动、碰撞、损伤产生等。事故发生后。根据国家GA41—2005《道路交通事故痕迹物证勘验》标准规定。交通事故现场痕迹包括路面痕迹、车体痕迹、人体痕迹、其它痕迹等勘验是确定交通事故责任和成因的主要依据。本文研究中通过对200起车外无防御能力的道路使用者（行人、自行车、三轮车、摩托车）与汽车碰撞事故现场痕迹。如人一车一道路位置。车辆的制动印痕、行驶速度、碰撞痕迹，人体致伤特点等各种客观的信息参数．寻找易于提取、利于计算分析、有助于事故重建的现场痕迹参数特点。以此建立起基于现场痕迹信息综合处理的事故再现参数体系。为后续重建交通事故碰撞过程研究提供参考依据。