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）团队负责采集能够模拟犯罪现场场景的鞋印图像，并向广大法医与科研社区公开共享。该数据集涵盖多种印模类型（全血印模、部分血印模与粉尘印模）、多种承痕地面（乙烯基地面与瓷砖地面）、专用提取技术（凝胶提取法），以及多种数字文件格式（TIF、XMP、CR3与JPG）。本数据集的采集遵循可复现性原则，采用简洁且明确的实验规程，搭配易于获取的实验材料完成。完整数据集包含936枚独特鞋印图像，对应3275个数字文件。数据采集由经过培训的志愿者完成：志愿者穿戴目标鞋具，踩踏印模介质后在承痕地面行走，以此形成鞋印，本次实验采用两种印模介质：飞溅血迹与石墨粉。针对血印样本，还需额外完成一次“轻踩”步骤以生成部分血印。血印制作完成后，会被送至摄影工作站，由研究人员标注并拍摄照片。粉尘印模（石墨粉印模）则需先使用凝胶提取膜进行提取，再送至摄影室，由研究人员取下提取膜、标注后拍摄照片。我们期望本数据集能够为科研人员、法医检验人员以及其他可从该大型鞋印数据集中获益的人群提供重要助力。公开可用的鞋印数据集往往较为稀缺，尤其是能够模拟犯罪现场场景的数据集，本数据集可有效填补这一空白。