A Mobile, Multi Camera Setup for 3D Full Body Imaging in Combination with Post-Mortem Computed Tomography Procedures

Abstract

Three dimensional (3D) models of deceased and injured people in combination with 3D scans of injury causing objects can assist forensic investigations in reconstructing event scenes. Medical imaging techniques, such as post-mortem computed tomography (PMCT) and post-mortem magnetic resonance imaging (PMMR), have been successfully applied to forensic investigations and can add beneficial value to standard autopsy examinations. These imaging modalities can be helpful for 3D reconstructions, especially when internal findings, such as bone fractures, organ damage and internal bleeding, are relevant for the investigation. However, none of these techniques can adequately visualize pattern injuries, such as boot prints and bite marks, or any type of blunt force trauma that forms distinct discolorations on the body’s surface. This is why 3D surface imaging techniques have been introduced to the forensic community. Unfortunately, many commercially available optical scanning systems are cost intensive, time consuming and can only be applied before or after a CT scan has been performed. In this article, we present a mobile, multi-camera rig based on close-range photogrammetry that is inexpensive, fast in acquisition time and can be combined with automated CT scanning protocols. The multi-camera setup comprises seven digital single-lens reflex (DSLR) cameras that are mounted on a mobile frame. Each camera is equipped with a remote control that can trigger the shutter release of all cameras simultaneously. In combination with a medical CT scanner, image acquisition of the multi camera setup can be included into an automated CT scanning procedure. In our preliminary study, textured 3D models of one side of the body were created in less than 15 minutes. The photo acquisition time combined with the modified CT scanning protocols lasted 3:34 minutes whereas the subsequent computation of a textured 3D model based on a low resolution mesh lasted 10:55 minutes. The mobile, multi-camera setup can also be used manually in combination with examination couches, lifting carts and autopsy tables. Finally, the system is not limited to post-mortem investigations but can also be applied to living people and may be used in clinical settings.