Automatic human identification based on dental X-ray radiographs using computer vision.

A person may be identified by comparison between ante- and post-mortem dental panoramic radiographs (DPR). However, it is difficult to find reference material if the person is unknown. This is often the case when victims of crime or mass disaster are found. Computer vision can be a helpful solution to automate the finding of reference material in a large database of images. The purpose of the present study was to improve the automated identification of unknown individuals by comparison of ante- and post-mortem DPR using computer vision. The study includes 61,545 DPRs from 33,206 patients, acquired between October 2006 and June 2018. The matching process is based on the Speeded Up Robust Features (SURF) algorithm to find unique corresponding points between two DPRs (unknown person and database entry). The number of matching points found is an indicator for identification. All 43 individuals (100%) were successfully identified by comparison with the content of the feature database. The experimental setup was designed to identify unknown persons based on their DPR using an automatic algorithm system. The proposed tool is able to filter large databases with many entries of potentially matching partners. This identification method is suitable even if dental characteristics were removed or added in the past.

Development and commissioning of an instrumented pneumatic device to simulate blunt- and sharp-force trauma.

Forensic investigators commonly interpret bone fracture patterns to estimate the force required to generate that trauma. Unfortunately, these estimates are limited to qualitative values such as "mild", "moderate" or "extreme" force. This work presents a new experimental forensic device developed to simulate blunt- and sharp-force trauma injuries, while recording the forces and velocities involved, so that a more quantitative relationship between force and trauma can be established. The machine design is described in some detail, its capabilities are outlined, and the results of the commissioning and validation tests are presented. Preliminary results for both blunt- and sharp-force testing of porcine ribs, conducted at 3.8m/s, indicate the average peak force (733±95N versus 392±73N), average force (334±49N versus 101±24N), and work (2.34±0.26J versus 0.68±0.09J) are significantly higher in the blunt case. The experimental data generated by this instrumented device will allow forensic investigators to create a better quantitative link between incident conditions (velocity, force, work) and the resulting fracture patterns.

Remote post-mortem radiology reporting in disaster victim identification: experience gained in the 2017 Grenfell Tower disaster.

On 14 June 2017 at 00:54 h, the worst residential fire since the conclusion of the Second World War broke out in Flat 16, 4th floor of the 24-storey residential Grenfell Tower Block of flats, North Kensington, West London, UK. Seventy-one adults and children died, including one stillbirth. All victims of the Grenfell Tower disaster who died at the scene underwent post-mortem computed tomography (PMCT) imaging using a mortuary-sited mobile computed tomography scanner. For the first time, to the authors' knowledge, the disaster victim identification (DVI) radiology reporting was undertaken remote to the mortuary scanning. Over an 11-week period, 119 scans were undertaken on 16 days, with up to 18 scans a day. These were delivered to a remote reporting centre at Leicester on 13 days with between 2 and 20 scans arriving each day. Using a disaster-specific process pathway, a team of 4 reporters, with 3 support staff members, trialled a prototype INTERPOL DVI radiology reporting form and produced full radiology reports and supporting image datasets such that they were able to provide 96% of prototype DVI forms, 99% of image datasets and 86% of preliminary reports to the DVI teams in London within one working day of image receipt. This paper describes the first use of remote radiology reporting for DVI and exemplifies how remote PMCT reporting can be used to support a DVI process of this scale.

A method for automatic forensic facial reconstruction based on dense statistics of soft tissue thickness.

In this paper, we present a method for automated estimation of a human face given a skull remain. Our proposed method is based on three statistical models. A volumetric (tetrahedral) skull model encoding the variations of different skulls, a surface head model encoding the head variations, and a dense statistic of facial soft tissue thickness (FSTT). All data are automatically derived from computed tomography (CT) head scans and optical face scans. In order to obtain a proper dense FSTT statistic, we register a skull model to each skull extracted from a CT scan and determine the FSTT value for each vertex of the skull model towards the associated extracted skin surface. The FSTT values at predefined landmarks from our statistic are well in agreement with data from the literature. To recover a face from a skull remain, we first fit our skull model to the given skull. Next, we generate spheres with radius of the respective FSTT value obtained from our statistic at each vertex of the registered skull. Finally, we fit a head model to the union of all spheres. The proposed automated method enables a probabilistic face-estimation that facilitates forensic recovery even from incomplete skull remains. The FSTT statistic allows the generation of plausible head variants, which can be adjusted intuitively using principal component analysis. We validate our face recovery process using an anonymized head CT scan. The estimation generated from the given skull visually compares well with the skin surface extracted from the CT scan itself.

Open-Source Tools for Dense Facial Tissue Depth Mapping of Computed Tomography Models.

Computed tomography (CT) scans provide anthropologists with a resource to generate three-dimensional (3D) digital skeletal material to expand quantification methods and build more standardized reference collections. The ability to visualize and manipulate the bone and skin of the face simultaneously in a 3D digital environment introduces a new way for forensic facial approximation practitioners to access and study the face. Craniofacial relationships can be quantified with landmarks or with surface-processing software that can quantify the geometric properties of the entire 3D facial surface. This article describes tools for the generation of dense facial tissue depth maps (FTDMs) using deidentified head CT scans of modern Americans from the Cancer Imaging Archive public repository and the open-source program Meshlab. CT scans of 43 females and 63 males from the archive were segmented and converted to 3D skull and face models using Mimics and exported as stereolithography files. All subsequent processing steps were performed in Meshlab. Heads were transformed to a common orientation and coordinate system using the coordinates of nasion, left orbitale, and left and right porion. Dense FTDMs were generated on hollowed, cropped face shells using the Hausdorff sampling filter. Two new point clouds consisting of the 3D coordinates for both skull and face were colorized on an RGB (red-green-blue) scale from 0.0 (red) to 40.0-mm (blue) depth values and exported as polygon (PLY) file format models with tissue depth values saved in the "vertex quality" field. FTDMs were also split into 1.0-mm increments to facilitate viewing of common depths across all faces. In total, 112 FTDMs were generated for 106 individuals. Minimum depth values ranged from 1.2 mm to 3.4 mm, indicating a common range of starting depths for most faces regardless of weight, as well as common locations for these values over the nasal bones, lateral orbital margins, and forehead superior to the supraorbital border. Maximum depths were found in the buccal region and neck, excluding the nose. Individuals with multiple scans at visibly different weights presented the greatest differences within larger depth areas such as the cheeks and neck, with little to no difference in the thinnest areas. A few individuals with minimum tissue depths at the lateral orbital margins and thicker tissues over the nasal bones (>3.0 mm) suggested the potential influence of nasal bone morphology on tissue depths. This study produced visual quantitative representations of the face and skull for forensic facial approximation research and practice that can be further analyzed or interacted with using free software. The presented tools can be applied to preexisting CT scans, traditional or cone beam, adult or subadult individuals, with or without landmarks, and regardless of head orientation, for forensic applications as well as for studies of facial variation and facial growth. In contrast with other facial mapping studies, this method produced both skull and face points based on replicable geometric relationships, producing multiple data outputs that are easily readable with software that is openly accessible.

Survey and Insights into Unmanned Aerial-Vehicle-Based Detection and Documentation of Clandestine Graves and Human Remains.

Numerous biological and archaeological studies have demonstrated the legitimacy of remote sensing in anthropology. This article focuses on detecting and documenting terrestrial clandestine graves and surface remains (CGSR) of humans using unmanned aerial vehicles (UAVs), sensors, and automatic processing algorithms. CGSR is a problem of complex decision making under uncertainty that requires the identification and intelligent reasoning about direct evidence of human remains and their environmental fingerprints. As such, it is as much an engineering and geospatial problem as it is an anthropology problem. This article is an effort to survey existing work across disciplines and to provide insights and recommendations to assist future research. To support our claims, preliminary experiments were performed at the Forensic Anthropological Research Facility at Texas State University using UAVs, hyperspectral imaging, thermal imaging, and structure from motion. Prior work, our experience, and preliminary results indicate that both great potential and extreme challenges face remote sensing of CGSR.

Comparative sensitivity and inhibitor tolerance of GlobalFiler® PCR Amplification and Investigator® 24plex QS kits for challenging samples.

In cases such as mass disasters or missing persons, human remains are challenging to identify as they may be fragmented, burnt, been buried, decomposed, and/or contain inhibitory substances. This study compares the performance of a relatively new STR kit in the US market (Investigator® 24plex QS kit; Qiagen) with the GlobalFiler® PCR Amplification kit (Thermo Fisher Scientific) when genotyping highly inhibited and low level DNA samples. In this study, DNA samples ranging from 1 ng to 7.8 pg were amplified to define the sensitivity of two systems. In addition, DNA (1 ng and 0.1 ng input amounts) was spiked with various concentrations of five inhibitors common to human remains (humic acid, melanin, hematin, collagen, calcium). Furthermore, bone (N = 5) and tissue samples from decomposed human remains (N = 6) were used as mock casework samples for comparative analysis with both STR kits. The data suggest that the GlobalFiler® kit may be slightly more sensitive than the Investigator® kit. On average STR profiles appeared to be more balanced and average peak heights were higher when using the GlobalFiler® kit. However, the data also show that the Investigator® kit may be more tolerant to common PCR inhibitors. While both STR kits showed a decrease in alleles as the inhibitor concentration increased, more complete profiles were obtained when the Investigator® kit was used. Of the 11 bone and decomposed tissue samples tested, 8 resulted in more complete and balanced STR profiles when amplified with the GlobalFiler® kit.

A forensic identification case and DPid - can it be a useful tool?

OBJECTIVE: The aim of this study was to show DPid as an important tool of potential application to solve cases with dental prosthesis, such as the forensic case reported, in which a skull, denture and dental records were received for analysis. MATERIAL AND METHODS: Human identification is still challenging in various circumstances and Dental Prosthetics Identification (DPid) stores the patient's name and prosthesis information and provides access through an embedded code in dental prosthesis or an identification card. All of this information is digitally stored on servers accessible only by dentists, laboratory technicians and patients with their own level of secure access. DPid provides a complete single-source list of all dental prosthesis features (materials and components) under complete and secure documentation used for clinical follow-up and for human identification. RESULTS AND CONCLUSION: If DPid tool was present in this forensic case, it could have been solved without requirement of DNA exam, which confirmed the dental comparison of antemortem and postmortem records, and concluded the case as a positive identification.

A forensic identification case and DPid - can it be a useful tool?

Abstract Objective The aim of this study was to show DPid as an important tool of potential application to solve cases with dental prosthesis, such as the forensic case reported, in which a skull, denture and dental records were received for analysis. Material and Methods Human identification is still challenging in various circumstances and Dental Prosthetics Identification (DPid) stores the patient's name and prosthesis information and provides access through an embedded code in dental prosthesis or an identification card. All of this information is digitally stored on servers accessible only by dentists, laboratory technicians and patients with their own level of secure access. DPid provides a complete single-source list of all dental prosthesis features (materials and components) under complete and secure documentation used for clinical follow-up and for human identification. Results and Conclusion If DPid tool was present in this forensic case, it could have been solved without requirement of DNA exam, which confirmed the dental comparison of antemortem and postmortem records, and concluded the case as a positive identification.

Technical note: Efficient removal of a PCR inhibitory agent (vivianite) found on excavated bones.

During a rescue excavation in October 2011, archaeologists discovered a mass grave with 10 individuals. The skeletons should belong to victims of the battle of Reichenberg between the Austrian and Prussian armies on April 21, 1757. Several bones of the skeletons were covered with a blue colored encrustation. Initial DNA analysis failed due to strong inhibition. Chemical analysis of the bluish encrustation indicated the presence of the iron phosphate mineral vivianite (Fe3(PO4)2·(H2O)8). This technical note describes a novel procedure for the removal of this inhibitory substance.

Age estimation by an analysis of spheno-occipital synchondrosis using cone-beam computed tomography.

The spheno-occipital synchondrosis has a relatively late ossification in comparison with other cranial base synchondroses, which makes it a point of interest for forensic age determination studies. The purpose of the present study was to evaluate the reliability of spheno-occipital synchondrosis development in age determination in a Turkish population and to evaluate the reproducibility and reliability of cone beam computed tomography (CBCT) in an evaluation of the fusion stages of spheno-occipital synchondrosis. CBCT mid-sagittal images of 238 (90 males and 148 females) patients between the ages of 7 and 25, with a mean age of 15.45±0.26 and 16.43±0.37, respectively, were examined by three Oral and Maxillofacial Radiologists who evaluated the degree of synchondrosis fusion using a four-stage system. A reevaluation of 50 cases was conducted for intraobserver assessment. Multiple statistical analyses were used to assess the correlation between age and the fusion stage, to compare gender and age according to stages, and to evaluate the inter- and intraobserver agreement. The mean ages for complete fusion (Stage 3) were 18 and 20 for females and males, respectively. The interobserver agreement ranged between substantial and perfect, while the intraobserver agreement was substantial for all three observers. Based on these results, CBCT, when available, might be the method of choice for age estimation using the spheno-occipital synchondrosis fusion stages. Evaluating spheno-occipital synchondrosis has a value for age estimation around the age of 18 years, which affects the legal decisions in Turkey.

Three dimensional surface analyses of pubic symphyseal faces of contemporary Japanese reconstructed with 3D digitized scanner.

Three dimensional pubic bone images were analyzed to quantify some age-dependent morphological changes of the symphyseal faces of contemporary Japanese residents. The images were synthesized from 145 bone specimens with 3D measuring device. Phases of Suchey-Brooks system were determined on the 3D pubic symphyseal images without discrepancy from those carried out on the real bones because of the high fidelity. Subsequently, mean curvatures of the pubic symphyseal faces to examine concavo-convex condition of the surfaces were analyzed on the 3D images. Average values of absolute mean curvatures of phase 1 and 2 groups were higher than those of phase 3-6 ones, whereas the values were approximately constant over phase 3 presumably reflecting the inactivation of pubic faces over phase 3. Ratio of the concave areas increased gradually with progressing phase or age classes, although convex areas were predominant in every phase.

Marcadores Inserção/Deleção (Indel): estudo de ancestralidade e identificação humana na população brasileira / Insertion/Deletion (Indel) markers: ancestry and human identification study in the Brazilian population

Os polimorfismos denominados Indels são variações de comprimento geradas por inserção ou deleção de um ou mais nucleotídeos em uma sequência de DNA. Estes marcadores genéticos vêm apresentando um grande potencial para fins forenses e populacionais por combinar características dos marcadores SNPs, tais como a capacidade de analisar fragmentos curtos (menores que 250pb) e baixas taxas de mutação, com a facilidade da genotipagem dos STR em uma única PCR, seguida de detecção dos fragmentos amplificados por eletroforese. Com o objetivo de avaliar a eficiência dos Indels em aplicações forenses e esclarecer os detalhes da formação de diferentes populações brasileiras através de dados genéticos, amostras populacionais de diferentes estados brasileiros foram genotipadas através de dois sistemas multiplex. O primeiro (indelplex-HID) foi otimizado para fins de Identificação Humana (HID) e inclui um grupo de 38 marcadores Indels selecionados por apresentarem altos valores de diversidade genética dentro das principais populações continentais. Já o segundo (46-AI-indels), foi selecionado para estudos de ancestralidade e é composto por um conjunto de 46 marcadores informativos de ancestralidade (AIMs). Nesse último caso, ao contrário do anterior, o sistema multiplex inclui marcadores com alta divergência nas frequências alélicas entre populações continentais. Na primeira etapa, o multiplex HID foi aplicado em uma amostra populacional do Rio de Janeiro e em uma amostra populacional dos índios Terena...

Indels are length polymorphisms created by the insertion or deletion of one or more nucleotides in a DNA sequence. This type of genetic marker is potentially very useful for forensic and population genetic applications because it combines some desirable SNP features, such as the possibility of being analyzed in small fragments (less than 250bp), and low mutation rate, and in the same way as for the STRs it is easily genotyped in a single PCR followed by capillary electrophoresis detection of the amplified fragments. In order to evaluate the efficiency of Indels in forensic applications, and clarify some details on the formation of different Brazilian populations through genetic data, population samples from different Brazilian States were genotyped through two Indel multiplex systems. The first (Indelplex-HID) has been optimized for Human Identification (HID), and includes a group of 38 Indel markers selected by presenting similarly high values of genetic diversity within the main continental populations. The second (46-AI-indels) was selected for studies of ancestry, and it is composed by a set of 46 ancestry informative markers (AIMs). The latter, unlike the first one, includes markers with high divergence in allele frequencies among populations. In a first stage, the multiplex HID was used to study a population sample of Rio de Janeiro and a population sample of Terena Amerindians...

DNA extraction method from bones using Maxwell® 16.

This paper describes the automated purification of DNA extracted from human bones using Maxwell® 16 bench top instrument. Analysis of nuclear short tandem repeats (STR) is invaluable in identification of human remains exhumed from mass graves in Croatia. Up to today 4683 skeletal remains have been recovered and for 897 human remains identity has not been determined. DNA has been extracted from 70% of all unidentified samples. For more than 90% of the samples nuclear STR profiles have been obtained using either organic phenol/chloroform method or silica-column purification for the extraction of DNA from bones or teeth. In order to evaluate a Maxwell® 16 DNA extraction performance 40 bone samples with different stage of decomposition were analyzed. The efficacy of manual silica based extraction and an automated purification was compared. The DNA yield per gram of starting material, removal of inhibitors and the quality of resulting STR profiles of the Maxwell extracts from duplicate amplifications were evaluated. The results show that Maxwell 16 platform can be used instead of manual DNA extraction procedures.

Measuring human remains in the field: Grid technique, total station, or MicroScribe?

Although three-dimensional (3D) coordinates for human intra-skeletal landmarks are among the most important data that anthropologists have to record in the field, little is known about the reliability of various measuring techniques. We compared the reliability of three techniques used for 3D measurement of human remain in the field: grid technique (GT), total station (TS), and MicroScribe (MS). We measured 365 field osteometric points on 12 skeletal sequences excavated at the Late Medieval/Early Modern churchyard in Vseruby, Czech Republic. We compared intra-observer, inter-observer, and inter-technique variation using mean difference (MD), mean absolute difference (MAD), standard deviation of difference (SDD), and limits of agreement (LA). All three measuring techniques can be used when accepted error ranges can be measured in centimeters. When a range of accepted error measurable in millimeters is needed, MS offers the best solution. TS can achieve the same reliability as does MS, but only when the laser beam is accurately pointed into the center of the prism. When the prism is not accurately oriented, TS produces unreliable data. TS is more sensitive to initialization than is MS. GT measures human skeleton with acceptable reliability for general purposes but insufficiently when highly accurate skeletal data are needed. We observed high inter-technique variation, indicating that just one technique should be used when spatial data from one individual are recorded. Subadults are measured with slightly lower error than are adults. The effect of maximum excavated skeletal length has little practical significance in field recording. When MS is not available, we offer practical suggestions that can help to increase reliability when measuring human skeleton in the field.

Digital radiological research in forensic dental investigation: case studies.

The advent of dental digital radiology and new portable X-ray devices allows the execution of periapical X-ray images not only in the dental surgery but also in hitherto difficult locations such as field military hospitals, archaeological excavation sites, morgues and in cases of house arrest. In this work authors evaluated the feasibility of Nomad Examiner (Aribex inc.) handheld X-ray device combined with a digital sensor and a portable pc in forensic odontology applications. Employed for the first time forensically during the 2004 Tsunami victim identification process, the Nomad Examiner has now passed all security and conformity requirements of US and EU regulations. Examples of the practical use and the technical features of this device are seen when employed in odontological assessment of skeletonised and carbonized individuals and the assessment of individuals under house arrest complaining dental lesions. Results from the use this portable device demonstrate the benefits of a dental radiological assessment during an autopsy with the aim of human identification and the importance of a complete dental assessment (clinical and radiological) when evaluating dental traumatic lesions of individuals who cannot visit a dental surgery. In the first example forensic dentist would work alongside a forensic pathologist. On the other hand in the second example an odontologist - dentist could be appointed as an expert witness directly by a Court.

New device for collecting intra-oral findings of unknown body.

In dental identification, the collection of intra-oral images is extremely important. We propose the Dental Watch(®) as a new device for collecting intra-oral findings in situations where sufficient jaw-opening or adequate lighting cannot be obtained in such cases of dead bodies within a day after death or burned bodies encountered in mass disaster. This device is an improved home video camera for taking intra-oral images. It is lightweight and cordless, allowing it to be operated with one hand, and an audio function allows comments to be made and recorded on obtaining findings at the same time as images are taken. In addition, this device allows images of the entire oral cavity to be taken comparatively easily, even when only a minimal degree of jaw movement is available. This device is extremely useful in situations where a single dentist inspector must obtain findings and make an accurate and detailed Dental Chart.

Genetic examination of the putative skull of Jan Kochanowski reveals its female sex.

We report the results of genetic examination of the putative skull of Jan Kochanowski (1530-1584), a great Polish renaissance poet. The skull was retrieved in 1791 by historian Tadeusz Czacki from the Kochanowski family tomb and became the property of the Czartoryskis Museum in Krakow. An anthropological study in 1926 questioned its male origin, which raised doubts about its authenticity. Our report presents genetic evidence that resolves this dispute. From the sole tooth we obtained a sufficient amount of DNA to perform the analysis of nuclear markers. The analysis of the sex-informative part of intron 1 in amelogenin, genotyped using AmpFiSTR® NGM PCR Amplification Kit and Powerplex® ESI17 Kit human identification systems, revealed the female origin of the tooth. The female origin was further confirmed by the analysis of a portion of amelogenin intron 2, a microsatellite marker located on the X chromosome, as well as by a lack of signal from Y chromosomal microsatellite markers and the sex-determining region Y marker. Data obtained for two hypervariable regions, HVI and HVII, in mitochondrial DNA showed that mtDNA haplotype was relatively frequent among contemporary Europeans. The analysis of a set of single nucleotide polymorphisms relevant for prediction of the iris color indicated an 87% probability that the woman had hazel or brown eye color.

Age estimation and the medial clavicular epiphysis: analysis of the age of majority in an Australian population using computed tomography.

This study was designed in order to assess the suitability of clavicular development in discriminating whether or not an individual has reached the age of 18 years. The development of the medial clavicular epiphysis was examined in an Australian population using computed tomography as the imaging modality. The sample consisted of individuals who were admitted to the Victorian Institute of Forensic Medicine, Melbourne, Australia, for the purposes of medico-legal death investigation. Comparisons were made with similar studies conducted on different populations in other countries, which revealed that the Australian population reaches maturity earlier, and the level of left/right asymmetry is higher than in other studies. The high degree of variation in fusion times is discussed, and the consequent effect upon the ability to use this epiphysis as a tool for determining if an individual has reached the age of 18 years is analysed. If an individual in this population has completely fused clavicles at stage 5, then for males they will be at least 18 years of age, with a 99% certainty of being at least 21, and for females they will be at least 20 years old. If at stage three then an individual of either sex will be at least 17 years of age.