FORMS-Locks: A Dataset for the Evaluation of Similarity Measures for Forensic Toolmark Images

We present a toolmark dataset created using lock cylinders seized during criminal investigations of break-ins. A total number of 197 cylinders from 48 linked criminal cases were photographed under a comparison microscope used by forensic experts for toolmark comparisons. In order to allow an assessment of the influence of different lighting conditions, all images were captured using a ring light with 11 different lighting settings. Further, matching image regions in the toolmark images were manually annotated. In addition to the annotated toolmark images and the annotation tool, extracted toolmark patches are provided for training and testing to allow a quantitative comparison of the performance of different similarity measures. Finally, results from an evaluation using a publicly available state-of-the-art image descriptor based on deep learning are presented to provide a baseline for future publications.