Bridging the gap in forensic toolmark evidence using advanced correlation methods

“例如在犯罪活动中，对表面使用的工具可能会在基材材料上留下印记。目前，法医调查依赖于由专家审查员对印痕的二维图像进行视觉比较，他们的结论基于意见。随着测量技术和比较技术的进步，目前的研究能力与其在刑事诉讼中的应用之间存在差距，这是本项目力求解决的问题。一个跨学科的方法，面积测量和相关将应用于工具标记调查，以实现一个客观的，可重复的方法，工具标记证据的法医比较。当工具与相对较软的基材材料接触时，就会产生塑性变形，从而留下工具的永久印痕。在法医领域，工具痕迹对于确定犯罪现场的事件至关重要，例如在入室盗窃的情况下，甚至当工具在骨头上留下印记时。虽然工具痕迹证据的比较已经在刑事诉讼中使用了几十年，但在法庭上接受的方法并没有改变。这导致科学报告中的方法被认为是主观的和不可重复的。虽然其他证据类型已经能够应用现代测量技术，从而产生基于科学标准的客观方法，但印象证据目前还无法做到这一点。因此，现有的方法与目前在法医比较中使用的方法之间存在差距。现代技术的应用将导致从二维测量到面测量的变化，从而获得更多关于工具标记地形的数据。这确保捕获了重要的数据，但是随着数据量的增加，需要确定正确的处理方法来实现有效的关联。因此，本研究将侧重于应用处理方法来实现计算比较，这是目前尚未实现的。将采用跨学科的方法，利用科学和工程技术来获取该领域目前所需的知识。本项目采用渐进式方法建立工具标记信息的面测量和比较方法。第一步将创建一个工具标记库，其中考虑了工具，操作和基板材料中的变量。这将允许对工具标记的创建进行法医相关的受控测试。使用先进的测量技术，如焦点变化、干涉测量技术和轮廓测量，将获得工具标记的地形。然后，计算处理将应用于分离突出信息以进行相关性，从而产生一种可以弥合当前方法与法庭之间差距的方法。”

"A tool used against a surface, for example in criminal activity, may leave an impression in the substrate material. Currently forensic investigation relies upon the visual comparison of 2D images of the impressions by expert examiners who base their conclusions on opinion. With the advancement of measurement technologies and comparison techniques, there is a gap between current capabilities in research and their use in criminal proceedings, which this project seeks to address. An interdisciplinary approach to areal measurement and correlation will be applied to toolmark investigation to achieve an objective, repeatable approach to the forensic comparison of toolmark evidence. When a tool comes into contact with a relatively softer substrate material, plastic deformation is caused whereby a permanent impression of the tool is imparted. Toolmarks are vital in within the forensic field for the determination of events at crime scenes, for example in instances of burglary or even when a tool leaves an impression in bone. While the comparison of toolmark evidence has been used in criminal proceedings for several decades, the methods that are accepted in court have not changed. This has resulted in methods being deemed as subjective and unrepeatable in scientific reports. While other evidence types have been able to apply modern measurement techniques, resulting in objective methods which are based on scientific standards, the same cannot currently be stated for impression evidence. Therefore, there is a gap between the methods available and those currently being used in forensic comparison. The application of modern techniques will result in a change from 2D to areal measurement, and with this comes the acquisition of significantly more data with regards to topography of the toolmark. This ensures that the salient data has been captured, however with a larger amount of data comes the need to determine the correct processing methods for efficient correlation. Therefore, this research will focus on the application of processing methods to achieve a computational comparison, which has not been achieved yet. An interdisciplinary approach will be applied in which both scientific and engineering techniques will be utilised to acquire the knowledge currently needed in the field.This project relies on a stepwise approach to build a method for the areal measurement and comparison of toolmark information. The first step will create a library of toolmarks in which variables in tool, operation and substrate material have been considered. This will allow forensically relevant controlled testing of the creation of the toolmark. Using advanced measurement techniques such as focus variation, interferometric techniques and profilometry, topography of the toolmark will be acquired. Computational processing will then be applied to separate the salient information for correlation, resulting in a method that can bridge the gap between current methods and the court room. "