Use of non-contact 3-D imaging for crime scene analysis

Walkthrough and assessment of the crime scene is the first step in criminal investigation. Classical 2-D methods only partially fulfill these requirements. We applied two 3-D optical digitizers to perform accurate 'in field' documentation of crime scenes: a laser stripe system and a time-of-flight system. They were used on three cases. The first is a real crime scene, i.e. a corpse buried in a woodland. The measurements were performed in a real context, characterized by the presence of specialized operators on the scene. The second case is the reconstruction of a crime simulated in a very large area, using a TOF system. This led to a measurement protocol for the registration of very large outdoor scenes combined to smaller, indoor views at high resolution (multiresolution models). The third case is the contactless 3-D measurement of soft tissues and bone lesions in the autoptic room. The use of optical range cameras is strategic to make the documentation process efficient, i.e., to store in a single document repository all measurement information, to selectively extract the information of interest, and to share the information with non-trained operators.