Opinion - (2022) Volume 7, Issue 5
Close range photogrammetry and optical surface scanning are two three-dimensional surface technologies that have recently developed into methods that are less expensive, more adaptable, and more accurate. However, the daily practice of forensic postmortem investigation has not yet fully tapped into their potential. In the current study, we compared the performance of stereophotogrammetry-based Vectra H11, a portable handheld surface scanner, and digital camera-based photogrammetry integrated with commercial Agisoft PhotoScan1 software. Three human subjects were chosen for the study: a 25-year-old woman who was still alive, two 63-year-old male forensic cases who had been admitted for postmortem examination at the Department of Forensic Medicine in Hradec Králové, Czech Republic, one of whom had died from traumatic, self-inflicted injuries (suicide by hanging), and the other of whom had been diagnosed with heart failure. With a Nikon 7000 digital camera and a handheld scanner, all three cases were concurrently documented in 3608 style and shot. Both procedures were used at different stages of the autopsy in addition to being used to record the pre-autopsy phase of the forensic cases. To create point clouds and 3D meshes, additional processing was applied to the sets of digital photos that were gathered (around 100 in each case). The number of points and polygons in the final 3D models (one pair for each person) were counted. They were then evaluated visually and statistically using the ICP alignment algorithm and a cloud point comparison technique based on closest point-to-point distances.
Postmortem documentation • Optical surface scanning • Photogrammetry
The gold standard for postmortem inspection, used to document the corpse's condition of preservation, the presence of distinctive somatic traits, external and internal injuries, and/or pathological alterations, is verbal description paired with two-dimensional photography [1]. The preservation of forensic evidence and the ability for other specialists to review the initial conclusions, avoid misdiagnoses, and maintain a high level of quality control are all made possible by the careful and exact documentation of the original pre-autopsy state, perishable findings, and sequential steps of an autopsy [2].
It is commonly known that 3D surface documentation outperforms 2D photography on a variety of fronts. It provides a threedimensional representation for any physical evidence in which all three dimensions are equally present without being lost or altered. When comparing different types of forensic evidence, such as pattern injuries against injury-inflicting instruments in weapon analysis, bone injuries, identification, or advanced morphometric analysis, 3D surface data are well suited to be the subject [3].
Present-day three-dimensional surface documentation can be carried out by a number of technologies with a comparatively steep learning curve. Technologies based on radio sources, laser or white light scanning, passive photogrammetry, video-imaging with infrared sensors, or touch measurement may be used for human body. Laser surface scanners work by using laser beams that gently scan the surface being scanned before reflecting back to a light sensor. The method calls for the scanned object to remain motionless for a longer amount of time for the majority of systems. This is not recommended for working with living people, but it is feasible when looking at crime scenes, bodies, and skeletal remains, as well as other types of forensic evidence like weapons (a shotgun, a knife), or personal items. One of the main drawbacks of laser scanning technology is that the resulting 3D digital models lack information about the original texture coloring unless a device has an optical camera system, like NextEngine, or the texture is applied to the surface using an appropriate editing programme, like Meshlab [4].
Contrarily, 3D optical surface scanning systems use two or more optical camera units to take pictures of the object's surface reflecting light from various angles (passive photogrammetry). By computing 3D surface points according to fundamental triangulation principles using digital images captured by converged cameras, surface depth information may then be reconfigured and high-resolution texture added. Alternatively, they consist of a camera system and a projection device that emits structured light, such as a pattern or a series of patterns, the images of which are subsequently captured on the surface [5]. The sources of depth information are the light pattern distortion and the camera calibration parameters. Only a second or two are needed for the scanned object to be still during the stereo-photogrammetry process, which is easily accomplished with dead human bodies but poses little trouble or discomfort while capturing living people. In contrast, structured light-based sensors that produce highresolution surface data of different volumes, like ATOS scanners, call for more regulated environments. This is helpful in forensic pathology, where it may be necessary to document a whole body or a modest impressed skull fracture on a daily basis [6].
The visual preservation of forensic evidence is greatly aided by photorealistic documentation. In a traditional environment, 2D photography is the most often utilised technique, but contemporary trends and techniques based on 3D technologies, medical imaging, and 3D graphics are increasingly being incorporated into daily life. But neither photogrammetry nor 3D scanning have been properly incorporated into standard workflow for forensic post-mortem assessment [7].
In this research, we used two methods that may be used in a regular forensic autopsy. One method only required a single digital camera and the right software application, while the other used a handheld optical scanner intended more for clinical than forensic uses. Both deceased and living subjects were studied in order to demonstrate the technology's full potential in the forensic environment.
It should be made clear right away that neither technique needs any specific training. This can be much appreciated in settings where digital photography techniques have never been used before. A technician, assistant, or pathologist can readily use both devices. Furthermore, neither method calls for the placement of any artificial reference marks on or near the recorded item. Both methods are risk-free and completely safe for all living things. However, the findings indicated that neither of them is particularly well-suited for obtaining full-body scans of living individuals. In our study, a lying living person served as the main topic of photography [8]. Both methods are risk-free and completely safe for all living things. However, the findings indicated that neither of them is particularly wellsuited for obtaining full-body scans of living individuals. In our study, a lying living person served as the main topic of photography. Generally speaking, photogrammetry-generated models had fewer mesh parameters (points, facets) than VH1-based models, but surprisingly, their file sizes were comparable (if only geometry was taken into account).
Despite the resolution variations, both methods successfully caught overall geometry and specific, diagnostically significant details. They differed in the surrounding or adjacent areas to the autopsy table or desk surface. These had irregular ragged edges created by the photogrammetry algorithm, which ultimately contributed to some of the diversity between individual models inside an individual. The possibility of other factors (such as an alignment algorithm, an undetected body displacement, etc.) contributing to the observed differences cannot be completely ruled out. The significant changes for the living person were concentrated on those body areas that were susceptible to minute movements brought on by physiological involuntary responses (thoracic and abdominal movements due to breathing) [9].
We thank the patient for allowing the case description.
The authors declare that they have no conflicts of interest
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Citation: Wilson, A. & Richards, S. 3-D Surface Documentation in Forensic Pathology. J. Forensic Pathol. 2022, 07 (5), 033-034
Received: 07-Sep-2022, Manuscript No. JFP-22-19432; Editor assigned: 09-Sep-2022, Pre QC No. JFP-22-19432 (PQ); Reviewed: 23-Sep-2022, QC No. JFP-22-19432 (Q); Revised: 28-Sep-2022, Manuscript No. JFP-22-19432 (R); Published: 07-Oct-2022, DOI: 10.35248/23322594.22.7(5).341
Copyright: ©2022 Wilson, A, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
