The Application of Photogrammetry in the Autopsy Room: A Basic, Practical Workflow

Applications of forensic anthropology methodology: accuracy of virtual face reproductions performed on the Tenchini collection

Facial reproduction validation uses the methodology typical of forensic anthropology to confirm the accuracy of three-dimensional reproductions of faces. Achieving high accuracy in virtual facial reproductions is still under study. In the present paper, the Tenchini collection, which contains wax reproductions of prisoners' faces and their skulls, was used. By creating facial reproductions on skulls from this collection, the result was compared with the real face of the person to whom the skull belongs. The three-dimensional volume of each examined skull of Tenchini collection was acquired via CT scan and photogrammetry. Subsequently, the virtual reproduction of each skull was processed using three-dimensional graphics software (ZBrush, Pixologic®). The morphological comparison parameters used in the field of personal identification by forensic anthropology were used. The blind procedure required the operator to see the mask subsequent to the facial reproduction phase, so that the facial reproduction cannot exploit the information that knowledge of the mask would have produced. The parameters used in the study of facial reproductions have shown discrepancies between the characteristics of the masks and the facial reproductions, partly expected because due to the lack of soft tissue on the skull. However, a high degree of accuracy in the facial reproductions performed due to the applied methodology was documented. The present study allowed us to observe how these parameters can be useful to study the accuracy of facial reproduction and identify what difficulties are encountered in producing a result close to the real appearance.

3D reconstruction of events: Search for a spatial correlation between injuries and the geometry of the body discovery site

The aim of the study was to assess the usefulness of analysing visual material in a 3D environment when examining spatial interrelations between the incident participants, tools, and space surrounding the incident site. Such analysis may provide information about the trauma mechanism, which may lead to the determination of probable events. This paper points to the potential of conducting research under 3D environment conditions on the example of a specific criminal incident-a suspected homicide. The aim of the study was to identify possible circumstances of the events with particular emphasis on the mechanism of death and the involvement of third parties. It was performed a comprehensive 3D reconstruction of the elements of the incident using different sources and forms of evidence, and consequently also different imaging, analysis, and synthesis technologies. The resulting 3D reconstruction and animation of the possible events serve to verify the investigative hypotheses. The paper combines a technical description of the research methodology with a forensic commentary, which ultimately creates an integral synthesis of the medicolegal assessment for trial purposes, while presenting the effectiveness of the research methods used. To sum up, the paper presents an experiment carried out under virtual conditions, impossible to execute under real conditions but critical for trial case analysis.

Phone cam array - An open-source, modular photogrammetry system made of Android phones

Photogrammetry is a 3D reconstruction technique using photographs of the target from multiple angles. Taking pictures around a static object with a single camera can yield high-quality models, but if the subject moves between images, 3D reconstruction might fail. One way to mitigate this is to use multiple cameras. This project aimed to develop a tool for fast and precise wound documentation for clinical forensic medicine. This paper describes a simple, low-cost modular system, where smartphones of different manufacturers are used as networked cameras. Exposure is initiated at the same time in all the phones with a simple circuit emulating a headset button press. A proof-of-concept device was built, where four phones (Huawei nova 8i (2 pcs), Samsung Galaxy S7 Edge, Oukitel K4000 Pro) were attached to a curved, 3D-printed, handheld frame. The average delay of image capture was 636 ms between the quickest and the slowest phones. When compared to the single-camera approach, the use of different cameras did not reduce the quality of the 3D model. The phone cam array was less susceptible to movement artefacts caused by breathing. Wound assessment was possible based on the 3D models created with this device.

The Introduction of a New Diagnostic Tool in Forensic Pathology: LiDAR Sensor for 3D Autopsy Documentation

Autopsy is a complex and unrepeatable procedure. It is essential to have the possibility of reviewing the autoptic findings, especially when it is done for medico-legal purposes. Traditional photography is not always adequate to record forensic practice since two-dimensional images could lead to distortion and misinterpretation. Three-dimensional (3D) reconstructions of autoptic findings could be a new way to document the autopsy. Besides, nowadays, smartphones and tablets equipped with a LiDAR sensor make it extremely easy to elaborate a 3D model directly in the autopsy room. Herein, a quality and trustworthiness evaluation of 3D models obtained during ten autopsies is made comparing 3D models and conventional autopsy photographic records. Three-dimensional models were realistic and accurate and allowed precise measurements. The review of the autoptic report was facilitated by the 3D model. Conclusions: The LiDAR sensor and 3D models have been demonstrated to be a valid tool to introduce some kind of reproducibility into the autoptic practice.

Application of photogrammetry in forensic pathology education of medical students in response to COVID-19

As the coronavirus disease 2019 (COVID‐19) pandemic forced universities to switch to distance online education, there was an urgent need to find some virtual/digital alternatives in order to continue teaching. Opportunities such as watching pre‐recorded autopsy videos or creating and analyzing post‐mortem computed tomography or magnetic resonance imaging with various 3D surface imaging techniques are usually time‐consuming and cost‐intensive. Photogrammetry, which allows the creation of 3D textured surface models from a series of overlapping photographs taken from varying viewpoints, is a less common approach compared with post‐mortem imaging. We created 3D autopsy case models for a special online forensic pathology course in which students could try the models. Then, formal feedback was requested regarding the possible application of this method in education. Most of the students were satisfied with the new method and ranked photogrammetry higher than the other available methods. Our results indicate that photogrammetry has a high potential in undergraduate education, especially in the case of distance education or in those countries where declining autopsy rates have resulted in a decline in the use of the autopsy as an educational tool. Photogrammetry can also be used as a supplementary tool in traditional autopsy‐based education and has potential applications in various fields of medical education.