ShoeCase: A data set of mock crime scene footwear impressions

This project's main objective is to create an open-source database containing a sizeable number of high-quality images of shoe impressions. The team at the Center for Statistics and Applications in Forensic Evidence (CSAFE) worked to collect images that could be representative of those found at crime scenes and made publicly available to the broader forensic and research communities. With mixed impression types (full blood impression, partial blood impression, and dust), flooring (vinyl and tile), lift techniques (gel lifts), and digital file types (TIF, XMP, CR3, and JPG). Our data was collected with the intention of reproducibility, using simple but specific protocols and easily accessible materials. The complete dataset includes 936 unique shoeprint images contained in 3,275 digital files. Data collection consisted of trained volunteers making shoe impressions on flooring with the 2 mediums: Spatter blood and graphite powder. They would wear the shoe, step in the material, and then walk on the flooring. For the blood prints a separate “lighter” step was made for a partial print. The blood prints were brought to the photography station where researchers labelled it and took a photograph. Graphite prints were covered with a gel lifter before being brought to the photography room. There the researchers removed the lift, then labeled and photographed it. We hope that our data will be of significant use for researchers, examiners, and anyone that could benefit from the use of a large dataset like this. Footwear datasets are often difficult to find, especially ones that resemble crime scenes, so our data can help fill that gap.本项目的核心目标是构建一个开源数据库，收录大量高质量的鞋印图像。法医统计与应用中心（Center for Statistics and Applications in Forensic Evidence, CSAFE）的团队致力于采集与犯罪现场鞋印具有代表性的图像，并将其向全球法医与科研社群公开。该数据集涵盖多种印模类型（全血印、半血印以及粉尘印）、承载基底（乙烯基地板与瓷砖）、提取技术（凝胶提取法）以及数字文件格式（TIF、XMP、CR3及JPG）。本数据集的采集遵循可复现性原则，采用简洁且明确的操作流程，搭配易于获取的实验材料。完整数据集共包含936张独特鞋印图像，对应3275个数字文件。数据采集环节由经过培训的志愿者完成：志愿者穿戴目标鞋子，踩踏两种介质（喷溅血液与石墨粉）后，在地板上留下鞋印。针对血印，还额外设置了“轻踩”步骤以生成半血印。采集完成的血印会被送至摄影工位，由研究人员标注并拍摄。石墨粉印则先使用凝胶提取膜覆盖，再移送至摄影室；研究人员随后取下提取膜，进行标注与拍摄。我们期望本数据集能够为科研人员、法医检验人员以及所有能从这类大型鞋印数据集获益的群体提供重要助力。目前鞋印类数据集往往难以获取，尤其是贴合犯罪现场场景的数据集，本数据集可填补这一空白。