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Craniofacial identification: techniques of facial approximation and craniofacial superimposition

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... Craniofacial superimposition has long been used in forensic science to assist identification of human skeletal remains when mainstream methods of DNA, radiographic comparison, and fingerprints cannot be used [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. To be employed, craniofacial superimposition requires an intact skull and a facial photograph (taken in life) of the person to whom the comparison is desired and/or to whom the skull is suspected to belong. ...
... To be employed, craniofacial superimposition requires an intact skull and a facial photograph (taken in life) of the person to whom the comparison is desired and/or to whom the skull is suspected to belong. The skull is photographed at the same orientation as the face, either using still-frame or motion picture photography, and the two images are registered at partial image transparency (superimposition) to assess their degree of anatomical correspondence [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. ...
... 1. Scale of the subject respective to the rest of the scene (Fig. 1a) 2. Size of subject features in relation to one another (Fig. 1b), e.g., nose on a face 3. What counts for an object's peripheral edges or horizons ( Fig. 1c) 4. Stretching of the subject along the 2D film plane (Fig. 1d) [50] In craniofacial superimposition, there is utility in differentiating which of the perspective-induced factors can be corrected by simple fixed aspect ratio scaling (i.e., effect 1 above), in contrast to the other effects that cannot be (effects 2-4). Subsequently, for this paper, we define perspective to collectively refer to all four of the abovementioned effects, while perspective distortion is expressly reserved only for the last three factors (2)(3)(4). These perspective distortion factors (2-4) are especially problematic for craniofacial superimposition because they cannot be compensated by simple fixed aspect ratio image scaling. ...
Article
Full-text available
Craniofacial superimposition concerns the photographic overlay of skulls and faces, for skeletal identification. As a phased method that depends on photographic optics first and anatomical comparisons second, superimposition is strongly underpinned by the physics of light travel through glass lenses. So that the downstream (and dependent) anatomical evaluations are not thwarted or erroneous identification decisions risked, it is critical that the optical prerequisites for valid image comparisons are met. As focus distance sets the perspective, the focus distance used for skull photography must be matched to that used at face photography, so that anatomically comparable 1:1 images are obtained. In this paper, we review the pertinent camera optics that set these nonnegotiable fundamentals and review a recently proposed method for focus distance estimation. We go beyond the original method descriptions to explain the mathematical justification for the PerspectiveX algorithm and provide an extension to profile images. This enables the first scientifically grounded use of profile view (or partial profile view) photographs in craniofacial superimposition. Proof of concept is provided by multiple worked examples of the focus distance estimation for frontal and profile view images of three of the authors at known focus distances. This innovation (1) removes longstanding trial-and-error components of present-day superimposition methods, (2) provides the first systematic and complete optical basis for image comparison in craniofacial superimposition, and (3) will enable anatomical comparison standards to be established from a valid grassroots basis where complexities of camera vantage point are removed as interfering factors.
... Craniofacial identification methods, developing over the past century, have proved useful towards forensic human identification especially when traditional records (DNA, dental records, fingerprints . . . ) are absent or difficult to obtain [1,2]. Craniofacial superimposition overlays the antemortem image(s) of a suspected individual over skull remains in order to assess morphological correspondence [3][4][5], whereas facial approximation attempts to predict a face solely from the cranial remains [4][5][6]. Both methods involve the use of facial soft tissue thickness (FSTT) values at various landmarks in the reconstruction of facial features [7,8]. ...
... Craniofacial identification methods, developing over the past century, have proved useful towards forensic human identification especially when traditional records (DNA, dental records, fingerprints . . . ) are absent or difficult to obtain [1,2]. Craniofacial superimposition overlays the antemortem image(s) of a suspected individual over skull remains in order to assess morphological correspondence [3][4][5], whereas facial approximation attempts to predict a face solely from the cranial remains [4][5][6]. Both methods involve the use of facial soft tissue thickness (FSTT) values at various landmarks in the reconstruction of facial features [7,8]. ...
... Although craniofacial identification methods are gaining momentum as viable methods for identification [4,5,10], the techniques have been shown to have inadequate reliability [11][12][13][14]. The facial approximation method has been considered inappropriate for positive scientific identification, with utility only towards public communication and gathering potential information regarding missing persons [15,16]. ...
Article
In forensic facial approximation, facial soft tissue thickness (FSTT) measurements play a major role. These values are affected by many factors such as ethnicity, age and sex, in addition to measurement errors. We hypothesize that an additional source of error is the lack of consideration of facial type in the assessment of FSTT norms. The purpose of this study was to: 1- evaluate the presence of significant effects of vertical facial type within the FSTT measurements in adults and 2- assess the correlations between FSTT and hard and soft tissue cephalometric measurements. The sample consisted of the lateral cephalometric radiographs of 222 adult individuals (87 males; 135 females, 23.49 ± 6.24 years of age) with normal occlusion and balanced profiles. Hard and soft tissue cephalometric measurements were taken, in addition to FSST at 10 facial landmarks. The sample was categorized into 3 vertical pattern groups based on the MP/SN angle: hypodivergent, normodivergent and hyperdivergent. Statistical analyses included MANOVA test and Pearson moment product for associations among variables. Statistically significant effect of vertical divergence on FSTT values was limited to the levels of Stomion, Labiomentale and Pogonion and FSTT measurements were associated with measurements related to the lower face (Lm and Pog) Moderate to high correlations between mandibular length and ramus length and FSTT values related to the lower face (LL, Lm and Pog mainly) emphasize further the important role of the underlying skeleton.
... The following points justify our choice of "craniofacial superimposition" as the most general and currently appropriate name for this forensic identification method. 2 1 Introduction to Craniofacial Superimposition -Craniofacial superimposition is the term widely found in the literature, which refers to all the tasks related to this forensic identification technique (Ubelaker et al. 1992;Yoshino et al. 1995;Cattaneo 2007). In particular, the most recent studies confirm the suitability of this terminology (Ranson 2009;Ibáñez et al. 2009aIbáñez et al. , 2011Pickering and Bachman 2012;Stephan 2009). -The term arises as a means to differentiate between the forensic technique itself and the technical devices used to tackle the identification problem. ...
... Finally, CFS should not be confused with craniofacial identification either. It is important to recognize that the latter is used as an umbrella term, which includes both CFS and the very different technique of facial approximation 3 (Clement and Ranson 1998;Wilkinson 2009;Stephan 2009). Both methods are underpinned by the knowledge of human craniofacial anatomy. ...
... Although it has been established that the outer canthus is located at the same height as the malar tubercle, there is no consensus as to the distance of the outer canthus from the orbital wall. The distance has been published as 1 mm (Sills 2004), 3-5 mm (Balueva et al. 2009;Angel 1978;Krogman and İşcan 1986;Stephan 2009), 5-7 mm (Wolff 1976Rosenstein et al. 2000), 8-10 mm (Couly et al. 1976), and 13 mm ( Anastassov and van Damme 1996). Where the malar tubercle is absent, the outer canthus can be positioned 8-11 mm below the line of the frontozygomatic suture (Stewart 1983;Krogman and İşcan 1986;Wolff 1976). ...
Book
This open access book is the first comprehensive guide to a new soft computing technique which is used in complex forensic cases. The chapters include detailed technical and practical overviews, and discussions about the latest tools, open problems and ethical and legal issues involved. The book will be of interest to researchers and practitioners in forensic medicine and computational intelligence. The book is closely associated with a successful research initiative, MEPROCS (New Methodologies and Protocols of Forensic Identification by Craniofacial Superimposition). The project collaborators were: S. Damas, O. Ibáñez, M.I. Huete, T. Kahana, C. Wilkinson, E. Ferguson, C. Erolin, P.T. Jayaprakash, R. Jankauskas, F. Cavalli, K. Imaizumi, R. Vicente, D. Navega, E. Cunha, A.H. Ross, E. Veselovskaya, A. Abramov, P. Lestón, F. Molinero, E. Ruiz, F. Navarro, J. Cardoso, F. Viegas, D. Humpire, R. Hardiman, J. Clement, A. Valsecchi, B.R. Campomanes-Alvarez, C. Campomanes-Alvarez, A.S. Çağdır, T. Briers, M. Steyn, M. Viniero, D.N. Vieira, and O. Cordón.
... T HE techniques used to identify a missing person from skeletal information have been under continuous investigation within forensic anthropology [1], [2]. Craniofacial superimposition (CFS) [3], one of the approaches in craniofacial identification [4], [5], involves superimposing a skull onto a number of ante-mortem images of an individual and the analysis of their morphological correspondence. Three consecutive stages for the whole CFS process have been distinguished in [6]: 1) Acquisition and processing of the skull and the ante-mortem facial photographs, together with the location of anatomical landmarks on the skull and the face; 2) Skull-face overlay (SFO), which focuses on achieving the best possible superimposition of a skull (or a skull 3D model) and a single ante-mortem image of a missing person. ...
... In fact, the anatomical distance between a cranial landmark and its corresponding facial point (soft tissue depth) is not considered. In reality, the thickness of the facial soft tissue differs for each corresponding pair of landmarks, varies among individuals and produces a mismatch among cranial and facial landmarks [5], [20]. Furthermore, another drawback of our proposals is that they have only been validated in a subjective way, based on the visual evaluation of the superimposition results by forensic experts. ...
... Craniofacial superimposition [3] is one of the approaches in craniofacial identification [4], [5]. It involves the superimposition of a skull with a number of ante-mortem images of an individual and the analysis of their morphological correspondence. ...
Article
Full-text available
Craniofacial superimposition involves the process of overlaying a skull with a number of ante-mortem images of an individual and the analysis of their morphological correspondence. Within the craniofacial superimposition process, the skull-face overlay stage focuses on achieving the best possible overlay of the skull and a single ante-mortem image of a missing person. This technique has been commonly applied following a non automatic trial-and-error approach. Automatic skull-face overlay methods have been developed obtaining promising results. In this work, we present two new variants that are an extension of existing 3D-2D methods to automatically superimpose a skull 3D model on a facial photograph. We have modeled the imprecision related to the facial soft tissue depth between corresponding pairs of cranial and facial landmarks which typically guide the automatic approaches. As an illustration of the model’s performance, the soft tissue distances associated to studies for Mediterranean population have been considered for dealing with this landmark matching uncertainty. Hence, we directly incorporate the corresponding landmark spatial relationships within the automatic skull-face overlay procedure. We have tested the performance of our proposal on 18 skull-face overlay instances from a ground truth dataset obtaining valuable results. The current proposal is thus the first automatic skull-face overlay method evaluated in a reliable and unbiased way.
... Prominence studies utilizing MRI [50] exophthalmometry [51] and palpation [48,49] all present results indicating a general agreement between current published standards. Studies on the position of the eyeball in the orbit from a frontal view seem to report different results depending on the method of assessment [48,[52][53][54][55]. The position of the inner (endocanthus) and outer (exocanthus) corners of the eye have been studied in detail, but there is no clear agreement between standards [48,[54][55][56][57][58][59][60]. ...
... Studies on the position of the eyeball in the orbit from a frontal view seem to report different results depending on the method of assessment [48,[52][53][54][55]. The position of the inner (endocanthus) and outer (exocanthus) corners of the eye have been studied in detail, but there is no clear agreement between standards [48,[54][55][56][57][58][59][60]. There is an agreement that the medial canthus is positioned approximately 2-5 mm lateral to the anterior lacrimal crest [54][55][56]61], but where exactly on the anterior lacrimal crest this measurement is taken from is unclear middle [48,49,56,62]. ...
... The position of the inner (endocanthus) and outer (exocanthus) corners of the eye have been studied in detail, but there is no clear agreement between standards [48,[54][55][56][57][58][59][60]. There is an agreement that the medial canthus is positioned approximately 2-5 mm lateral to the anterior lacrimal crest [54][55][56]61], but where exactly on the anterior lacrimal crest this measurement is taken from is unclear middle [48,49,56,62]. The eyelid pattern has been studied using palpation and anthropometry studies (comparison of skulls with ante-mortem images) [48,63]. ...
Article
Full-text available
In this manuscript, the past, present and future of the identification of human remains based on craniofacial superimposition is reviewed. An analysis of the different technological approaches developed over time is offered in conjunction with a new classification based on the technology implemented throughout the diverse phases of the process. The state of the art of the technique, in the academic and forensic realms, is reflected in an extensive international survey that includes over one hundred experts worldwide. The results of the survey indicate the current relative importance of the technique, despite of its controversial nature within the scientific community. Finally, the future challenges to be faced to justify the use of this technique for either profiling, exclusion or identification purposes are discussed. Copyright © 2015. Published by Elsevier Ireland Ltd.
... Apart from the aforementioned identification methods, thanks to the availability of photographs belonging to 11 individuals, identification through craniofacial superimposition (CFS) was carried out. This technique involves the direct comparison of the image or 3D model of an unknown skull with the photograph of a known person, analyzing the morphological correspondences to determine, with a reasonable degree of confidence, whether they belong to the same person or not [1][2][3]. ...
... However, many others believe that CFS is more suitable for exclusion of individuals or as a source of corroborative evidence. In between, some authors [1,2] claim that it is not possible to make firm statements about the overall reliability of CFS methods due to the small number of published studies, the small samples used, and the significant number of limitations of these studies (as will be discussed below). Moreover, in no case have they been replicated. ...
Article
Full-text available
In 2017, a series of human remains corresponding to the executed leaders of the “January Uprising” of 1863–1864 were uncovered at the Upper Castle of Vilnius (Lithuania). During the archeological excavations, 14 inhumation pits with the human remains of 21 individuals were found at the site. The subsequent identification process was carried out, including the analysis and cross-comparison of post-mortem data obtained in situ and in the lab with ante-mortem data obtained from historical archives. In parallel, three anthropologists with diverse backgrounds in craniofacial identification and two students without previous experience attempted to identify 11 of these 21 individuals using the craniofacial superimposition technique. To do this, the five participants had access to 18 3D scanned skulls and 14 photographs of 11 different candidates. The participants faced a cross-comparison problem involving 252 skull-face overlay scenarios. The methodology follows the main agreements of the European project MEPROCS and uses the software Skeleton-ID™. Based on MEPROCS standard, a final decision was provided within a scale, assigning a value in terms of strong, moderate, or limited support to the claim that the skull and the facial image belonged (or not) to the same person for each case. The problem of binary classification, positive/negative, with an identification rate for each participant was revealed. The results obtained in this study make the authors think that both the quality of the materials used and the previous experience of the analyst play a fundamental role when reaching conclusions using the CFS technique.
... Craniofacial superimposition compares features of a recovered skull thought to be of medico-legal interest with antemortem photographs of a missing person who might be represented by the remains. This technique may be employed when positive identification has not been accomplished through molecular analysis, dental reconstruction comparison or anthropological radiographic assessment [18]. Usually, the method is utilized when complete skulls or crania are available for comparison [19], but attempts have been made using even fragmentary evidence [20]. ...
... Once clear images are found that can be used to compare the recovered crania, forensic anthropologists must take the time to orient the skull, often using Q-tips as place markers, in order to be able to lay the images properly over each other [21]. The techniques of comparison have become more complex and sophisticated [18,19] but primarily allow exclusion rather than positive scientific identification. Images are often pulled from police records, surveillance or directly from relatives of the possible individual. ...
Article
Full-text available
This review covers previous and current literature on the impact of forensic anthropologists on the positive scientific identification of human remains and aims to provide an understanding of what information a forensic anthropologist can contribute to an investigation. Forensic anthropologists looking to identify human remains study traits of the skeleton and any orthopedic devices present. In order to obtain a positive scientific identification, evidence that is both sufficiently unique to the individual and comparable to available antemortem data from that individual must be found. The increased availability of radiographs, scans and implants in recent decades has facilitated the identification process. When these records are unavailable, other techniques, such as craniofacial superimposition and facial approximation, can be employed. While these methods may assist the identification process, they are most useful for exclusion of certain individuals and gathering leads from the public. Forensic anthropologists have heavily relied on the skull and its complexities for identification – typically focusing on the frontal sinus and other unique traits. Post-cranial remains can provide important information about bone density, possible disease and other characteristics that may also be utilized. Techniques used to positively identify individuals are not limited to medicolegal death investigations, and have been useful in other legal contexts. In the future, a team approach, utilizing all the information gathered by multiple forensic scientists – including forensic anthropologists – will most likely become more common.
... Craniofacial superimposition (CFS) [2,3,4,5,6,7] is one of the most relevant skeleton-based identification techniques. It involves the process of overlaying a skull image (or a skull 3D model) with a number of AM images of an individual and the analysis of their morphological correspondence. ...
... The correspondence between facial and cranial anthropometric landmarks is not always symmetrical and perpendicular; some landmarks are located in a higher position in the alive person face than in the skull, and some others do not have a directly related landmark in the other set. Besides, the facial soft tissue depth varies for each cephalometric landmark, as well as for different person groups (based on age, race, and gender) [7,24]. ...
... Craniofacial superimposition (CS) (Krogman and Iscan 1986;Iscan 1993;Stephan 2009) is a forensic process where photographs or video shots of a missing person are compared with the skull that is found. By projecting both photographs on top of each other (or, even better, matching a three-dimensional skull model obtained scanning an unidentified human skull against the face photo/series of video shots), the forensic anthropologist can try to establish whether that is the same person. ...
... Due to the inability of the ME to be in concordance with the visual SFO results we are planning to design new the fitness function Finally, we are planning to tackle the inherent matching uncertainty regarding each pair of cephalometric-craniometric landmarks (see Sect. 3). With the support of the forensic anthropologists collaborating with us and taking Stephan and Simpson's works (Stephan andSimpson 2008a, 2008b) as a base, we aim to deal with this partial matching situation by using fuzzy sets and fuzzy distance measures. ...
Article
Full-text available
Craniofacial superimposition is a forensic process where photographs or video shots of a missing person are compared with the skull that is found. By projecting both photographs on top of each other (or, even better, matching a scanned three-dimensional skull model against the face photo/video shot), the forensic anthropologist can try to establish whether that is the same person. The whole process is influenced by inherent uncertainty mainly because two objects of different nature (a skull and a face) are involved. In previous work, we categorized the different sources of uncertainty and introduced the use of imprecise landmarks to tackle most of them. In this paper, we propose a novel approach, a cooperative coevolutionary algorithm, to deal with the use of imprecise cephalometric landmarks in the skull–face overlay process, the main task in craniofacial superimposition. Following this approach we are able to look for both the best projection parameters and the best landmark locations at the same time. Coevolutionary skull–face overlay results are compared with our previous fuzzy-evolutionary automatic method. Six skull–face overlay problem instances corresponding to three real-world cases solved by the Physical Anthropology Lab at the University of Granada (Spain) are considered. Promising results have been achieved, dramatically reducing the run time while improving the accuracy and robustness.
... Facial reconstruction is a technique that estimates an individual face from a human skull, using established craniofacial standards, for forensic identification or archaeological investigation. While there are different facial reconstruction methods (Prag and Neave 1997;Taylor 2000;Wilkinson 2005;Iscan and Steyn 2013;Stephan and Claes 2016), most follow established and tested anatomical standards and procedural guidelines to create face shape (Wilkinson et al. 2006;Lee et al. 2012). Once the facial reconstruction shape is produced, a variety of primary, secondary and tertiary skin 'textures' are added, including wrinkles, creases and pores, followed by the addition of eyes, hair and additional accoutrements or clothing, plus colour information (Wilkinson 2010;Roughley and Wilkinson 2019;Roughley 2020). ...
Chapter
Facial reconstruction is a technique that can be used to estimate individual faces from human skulls. The presentation of 3D facial reconstructions as photo-realistic depictions of people from the past to public audiences varies widely due to differing methods, the artists' CGI skillset, and access to VFX software required to generate plausible faces.This chapter describes three digital methods for the addition of realistic textures to 3D facial reconstructions; a 2D photo-composite method, a 3D digital painting and rendering method, and a previously undescribed hybrid 2.5D method.These methods are compared and discussed in relation to artistic proficiency, morphological accuracy and practitioner bias.
... [2][3][4] Craniofacial superimposition overlays a number of antemortem images of a missing person with an unidentified skull, to assess their structural similarity. [5][6][7] Although this paper focusses on forensic applications of the relationship between the skull and the overlying soft tissues, this relationship is relevant to several medical fields. Insight from reference data about hard and soft tissue associations could benefit surgeons and orthodontists treating dentofacial deformities; for whom obtaining harmonious facial characteristics and functionality are important considerations during diagnosis and treatment. ...
... involves destruction of facial features including dentition or complete decapitation and can extend to the removal of hands and feet. Decapitation rules out craniofacial comparisons and approximations (Stephan and Claes, 2016;Wilkinson, 2007) as well as dental examination, while fingerprints -if available and recoverable -may not lead to an immediate identification if the victim's fingerprints have never been taken and entered into a database. Without other distinguishing features such as jewelry, clothing or body art (Starkie, 2011), identification of mutilated murder victims becomes nigh impossible using traditional investigative techniques. ...
Article
Fragmented and badly damaged commingled human remains present a tough challenge for their identification pursuits in forensic anthropology. Thousands of unknown human remains along with items of contextual identity, reportedly belonging to 282 Indian sepoys killed in 1857, were exhumed mon-scientifically from a disused ancient well at Ajnala (Amritsar, India). In this manuscript, the non-scientific excavation of unknown human remains from the abandoned well, their forensic anthropological strategies for identification purposes, challenges being faced and future possibilities of their biological profiling have been discussed. Multiple methods and techniques like anthropological examinations, odontological profiling, radiological analyses, stable isotope and mitochondrial DNA (mtDNA) analyses were applied to few bones and teeth collected from the Ajnala skeletal assemblage. Though majority of studied bones and teeth were found belonging to adult males, very few of them had morphological, osteological and molecular features questioning the authenticity and validity of the written records. Due to certain ambiguous findings or gaps observed between the anthropological analyses of the Ajnala skeletal remains and the reported versions about their affiliations; certain advanced radiological, chemical and molecular techniques were applied to estimate their probable age, sex and populational affinity. The obtained radiological, isotopic and molecular signatures of the remains were compared with the available databases to estimate their affinity with the individuals of geographic area to whom the remains reportedly belonged to. The maternally inherited mtDNA haplogroup assignments, and stable isotope analysis of carbon and oxygen suggested that the studied human remains belonged to the individuals from West Bengal, Bihar, Odisha, Awadh (presently in Uttar Pradesh) and parts of Meghalaya and Manipur as potential regions of their geographic identity and thus, attributing the victims to be non-local to the site. However, merely on the basis of forensic anthropological examinations of very few bones and teeth (collected out of a huge collection of thousands of bones and teeth); it would be just an unqualified and sweeping conclusion to claim their identity as adult or nonadult, male or female, local or non-local, victims of 1857 mass killings or to the victims of ceremonial sacrifice or criminal activities committed in the past. A sufficient number of bones and teeth along with items of personal identity needs to be examined with multiple scientific techniques to arrive at some valid conclusions about their biological identity.
... involves destruction of facial features including dentition or complete decapitation and can extend to the removal of hands and feet. Decapitation rules out craniofacial comparisons and approximations (Stephan and Claes, 2016;Wilkinson, 2007) as well as dental examination, while fingerprints -if available and recoverable -may not lead to an immediate identification if the victim's fingerprints have never been taken and entered into a database. Without other distinguishing features such as jewelry, clothing or body art (Starkie, 2011), identification of mutilated murder victims becomes nigh impossible using traditional investigative techniques. ...
Chapter
This chapter provides some background and applications of stable isotope analysis in the context of humanitarian forensic science to illustrate the contribution that isotopic profiling can make to an investigation of an unidentified decedent. It also describes a few of the isotopic tools and data resources currently available to forensic investigators. Human tissues can be categorized into tissues with a longer‐term memory such as bone and teeth and tissues with a shorter‐term memory such as hair and nail. Isotopic profiling of human hair has received a good deal of attention in the past decade, and a rich repository of published knowledge exists on the particular challenge that is H isotope abundance analysis of hair. The isotopic profiles of human tissues such as bone, teeth, hair and nail hold great potential for forensic investigations by providing valuable information regarding an unidentified decedent's life history that cannot be obtained by any other analytical method.
... CFA is a method that refers to the structural details of the skull to help reproduce the soft tissue features of an individual's face (2)(3)(4). CFS alternatively refers to existing antemortem images of a missing person, where the image and unidentified skull or skull model are compared using a system of overlays to examine their structural similarity (5)(6)(7). Both these practices rely on valuable information of the relationship and common patterns between hard and soft tissue structures. ...
Article
Full-text available
Standards for estimating mouth width and Cupid’s bow width in craniofacial approximation and superimposition are limited. Currently, the only guideline for mouth width, using direct skeletal references, is a general rule indicating a 75% inter‐canine to mouth width ratio. The philtrum, which closely corresponds to the Cupid’s bow, is said to be equal to the inter‐superior prominences of the maxillary central incisors. This study tested these guidelines against newly generated regression models and mean values. Cone‐beam CT scans of 120 black and 39 white southern African adults were used. Comparative hard and soft tissue measurements were taken using a 3D DICOM viewer. Regression equations accounting population, sex, and approximate age variables (20–39 and 40+ years), utilizing maxillary inter‐canine width to estimate mouth width and maxillary central–lateral incisor junction width to estimate Cupid’s bow width, performed statistically best. The regression models were more reliable than existing standards in validation tests.
... Purpose: this method has most commonly been used to exclude subjects whose face anatomy does not match that of the skull [181][182][183][184][185][186], but it has also been used, perhaps more controversially, for identification [187][188][189]. In certain (rare) circumstances where all ideal conditions are met (e.g. ...
Article
Full-text available
Facial imaging is a term used to describe methods that use facial images to assist or facilitate human identification. This pertains to two craniofacial identification procedures that use skulls and faces—facial approximation and photographic superimposition—as well as face-only methods for age progression/regression, the construction of facial graphics from eyewitness memory (including composites and artistic sketches), facial depiction, face mapping and newly emerging methods of molecular photofitting. Given the breadth of these facial imaging techniques, it is not surprising that a broad array of subject-matter experts participate in and/or contribute to the formulation and implementation of these methods (including forensic odontologists, forensic artists, police officers, electrical engineers, anatomists, geneticists, medical image specialists, psychologists, computer graphic programmers and software developers). As they are concerned with the physical characteristics of humans, each of these facial imaging areas also falls in the domain of physical anthropology, although not all of them have been traditionally regarded as such. This too offers useful opportunities to adapt established methods in one domain to others more traditionally held to be disciplines within physical anthropology (e.g. facial approximation, craniofacial superimposition and face photo-comparison). It is important to note that most facial imaging methods are not currently used for identification but serve to assist authorities in narrowing or directing investigations such that other, more potent, methods of identification can be used (e.g. DNA). Few, if any, facial imaging approaches can be considered honed end-stage scientific methods, with major opportunities for physical anthropologists to make meaningful contributions. Some facial imaging methods have considerably stronger scientific underpinnings than others (e.g. facial approximation versus face mapping), some currently lie entirely within the artistic sphere (facial depiction), and yet others are so aspirational that realistic capacity to obtain their aims has strongly been questioned despite highly advanced technical approaches (molecular photofitting). All this makes for a broad-ranging, dynamic and energetic field that is in a constant state of flux. This manuscript provides a theoretical snapshot of the purposes of these methods, the state of science as it pertains to them, and their latest research developments.
... It is a craniofacial identification [45,42] approach in which a number of antemortem (AM) images of a missing person are superimposed over a skull to 5 determine if they belong to the same subject by analyzing their morphological correspondence. ...
Article
Full-text available
Craniofacial superimposition (CFS) is a skeleton-based technique that aims to provide identity to a skull through its superimposition with one or more photographs of candidate missing people. While traditionally performed by forensic experts, computer-aided CFS methods can now provide substantial speedups and are quickly progressing towards a large degree of automation. A current major limitation concerns the position of the mandible, which is required to be manually set by the expert beforehand in order to reproduce the facial expression of the subject in each available photograph. This is time-consuming and prone to errors. In this work, we address this issue by extending the state-of-the-art genetic algorithm-based method with the ability to allocate the mandible in the right position according to an anatomical model. Based on a dataset of simulated ante-mortem images with different mandible apertures and facial poses, we prove experimentally that the proposed method is able to effectively tackle cases displaying a much larger range of mandible positions. In fact, thanks to the new genetic design, it is able to outperform the original method, even when the mandible aperture is very small.
... Among them, the design of computer-aided craniofacial superimposition (CFS) [9] methods is increasing and it has experienced a boom over the past twenty years [10]. CFS is a representative technique of forensic anthropology, included within the approaches in craniofacial identification [11]. This process involves the superimposition of a skull with a number of ante-mortem (AM) images of a missing person and the analysis of their morphological correspondence to determine if they belong to the same subject. ...
... Within the various postmortem identification techniques, Craniofacial Superimposition (CFS) [1][2][3] is considered a controversial technique within the scientific community. The lack of unified working protocols among practitioners as well as the absence of commonly accepted standards in the application of the technique, led to contradictory arguments regarding CFS reliability [4][5][6]. ...
Article
Craniofacial superimposition (CFS) involves the process of overlaying a skull with a number of ante-mortem images of an individual and the analysis of their morphological correspondence. The lack of unified working protocols and the absence of commonly accepted standards, led to contradictory consensus regarding its reliability. One of the more important aims of ‘New Methodologies and Protocols of Forensic Identification by Craniofacial Superimposition (MEPROCS)’ project was to propose a common framework for CFS, what can be considered the first international standard in the field. The framework aimed to serve as a roadmap for avoiding particular assumptions that could bias the process. At the same time, it provides some empirical support to certain practices, technological means, and morphological criteria expected to facilitate the application of the CFS task and to improve its reliability. In order to confirm the utility and potential benefits of the framework use, there is a need to empirically evaluate it in CFS identification scenarios as close as possible to the reality. Thus, the purpose of this study is to validate the CFS framework developed. For that aim 12 participants were asked to report about a variable number of CFS following all the recommendations of the framework. The results are analysed and discussed according to the framework understanding and fulfilment, the participants’ performance, and the correlation between expected decisions and those given by the participants. In view of the quantitative results and qualitative examination criteria we can conclude that those who follow the MEPROCS recommendations improve their performance.
... Craniofacial superimposition (CFS) [1] is one of the approaches used in craniofacial identification [2,3]. It involves the superimposition of a skull (or a skull model) over a number of ante mortem images of an individual and the analysis of their morphological correspondence. ...
Article
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Craniofacial superimposition has the potential to be used as an identification method when other traditional biological techniques are not applicable due to insufficient quality or absence of ante-mortem and post-mortem data. Despite having been used in many countries as a method of inclusion and exclusion for over a century it lacks standards. Thus, the purpose of this research is to provide forensic practitioners with standard criteria for analysing skull-face relationships. Thirty-seven experts from 16 different institutions participated in this study, which consisted of evaluating 65 criteria for assessing skull-face anatomical consistency on a sample of 24 different skull-face superimpositions. An unbiased statistical analysis established the most objective and discriminative criteria. Results did not show strong associations , however, important insights to address lack of standards were provided. In addition, a novel methodology for understanding and standardizing identification methods based on the observation of morphological patterns has been proposed. Crown
... 5a. Facial approximations cannot be treated as a reliable tool of individual identifi cation (Stephan, Henneberg 2001), chiefl y because many characteristics which are taken into account during identifi cation cannot be safely reconstructed using the skull (Stephan 2009;Stephan, Henneberg 2006;George 1993;cf. Sołtysiak, Kozłowski 2009). ...
Chapter
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Archaeological interpretations are frequently affected by wishful thinking. This problem may be reduced by consciously arranging the interpretation process, e.g. with use of a simple interpretative index. The fi rst step is the defi nition of all possible and imaginable interpretations of a given phenomenon, then all possible pieces of evidence pro or contra the given interpretation should be identifi ed and listed. When the list of interpretations and the list of criteria are ready, our evaluation of signifi cance of gathered evidence can be arranged in a table using the following scale: –2 (the piece of evidence falsifi es a given interpretation), –1 (it weakens the interpretation), 0 (the criterion is not adequate for a given interpretation), +1 (the piece of evidence supports the interpretation), +2 (it confi rms the interpretation). The interpretative index is the arithmetic mean of all positive and negative values for a given interpretation. At the same time it is possible to calculate the diagnostic value of the whole gathered evidence as a proportion of the criteria for which the obtained values were different from zero. The ultimate result of such somewhat formalised procedure is the accepted interpretation with the highest interpretative index. The effectiveness of such method is tested here on a case study of the cranium 13/05 found in the Frombork cathedral and identified as the remains of Nicolaus Copernicus.
... The Russian anthropologist and archaeologist Mikhail Mikhaylovich Gerasimov, 1907-1970, is internationally renowned for his method of building faces from skulls, both in paleoanthropology and in forensic anthropology (Gibson 2008, Đşcan, Steyn 2013, Nature Editorial 1970, Prag, Neave 1997, Stephan 2009, Taylor 2001, Wilkinson 2004. Although he was not the first to undertake such methods, prior to him, facial reconstruction methods were thought only to produce a facial resemblance in terms of "race" (Eggeling 1913, Kollmann, Büchly 1898, Merkel 1900. ...
... Craniofacial superimposition (CFS) [1], one of the approaches in craniofacial identification [2,3], is a forensic process where a number of ante-mortem images of a missing person are superimposed with the ...
Article
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Skull–face overlay is the most time-consuming and error-prone stage in craniofacial superimposition, an important skeleton-based forensic identification technique. This task focuses on achieving the best possible overlay of an unknown skull found and a single ante-mortem image of a candidate missing person. The process is influenced by some sources of uncertainty since two objects of different nature are involved, i.e. a skull and a face. In previous works we have developed a computer-aided craniofacial superimposition system aimed to assist forensic anthropologists in obtaining the best possible skull and face overlay. The system has successfully allowed us to reduce the processing time, simplify the forensic anthropologists' work, and make the process more objective and reproducible. Our approach is based on automatically overlaying a skull three dimensional model onto a facial photograph by minimizing the distance between two subsets of corresponding cranial and facial landmarks. The proposed method properly deals with the inherent uncertainty sources to the skull–face overlay process by considering fuzzy sets to model imprecise landmark location, and imprecise cranial and facial landmarks spatial correspondence (resulting from the presence of soft tissues in the face). Accordingly, our methodology requires computing two kinds of distance metrics: between a point and a fuzzy set, and between two fuzzy sets. This contribution is devoted to study the performance and influence of the most significant and suitable fuzzy distances proposed in the specialized literature, as well as other new ones proposed, on our skull–face overlay system. In particular, we have tested the behavior of our automatic method when considering eight different distance measurements. The system performance has been objectively evaluated considering 18 case studies resulting from a ground truth dataset following a rigorous statistical experimental setup. The fact that the choice of a good distance metric is crucial to our method has been demonstrated since it significantly affects the quality of the final solutions. It has been shown that our skull–face overlay approach presents the best performance using the weighted mean distance in most of the cases and that the results are both more accurate and robust than the other studied metrics.
... Skeleton-based identification methods have been under continuous investigation within the forensic anthropology and odontology communities [1,2]. Craniofacial superimposition (CFS) [3], one of the approaches in craniofacial identification [4,5], is a representative technique of this kind. It involves the superimposition of a skull with a number of antemortem (AM) images of a missing person and the analysis of their morphological correspondence to determine if they belong to the same subject. ...
Conference Paper
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Craniofacial superimposition is a forensic identification method involving the overlay of a skull over the available ante-mortem photographs of a candidate missing person face and the subsequent analysis of their anatomical correspondence. Within this process, the decision making stage focuses on determining the degree of support of being the same person or not based on the analysis of some criteria assessing the skull-face morphological correspondence. That decision is usually obtained in a non automatic and subjective way. We aim to automate the decision making process using computer vision and soft computing methods to assist the forensic anthropologist. In this work, we present a first approach to model one of the criteria followed by forensic experts: the analysis of the consistency of bony and facial chin outlines. We show some preliminary results over 82 skull-face overlay instances and discuss future research directions.
... Skeleton-based identification methods have been under continuous investiga- tion within the forensic anthropology and odontology communities [1]. Craniofacial superimposition (CFS) [2], one of the approaches in craniofacial identification [3,4], is a representative technique of this kind. It involves superimposing a skull onto a number of ante-mortem (AM) images of a missing person and the analysis of their morphological correspondence to determine if they belong to the same subject. ...
Article
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Craniofacial superimposition is one of the most relevant skeleton-based identification techniques. Within this process, the skull-face overlay stage focuses on achieving the best possible overlay of a skull found and an ante mortem image of a candidate person. In previous work, we proposed an automatic skull-face overlay method, based on evolutionary algorithms and fuzzy sets. The following stage, decision making, consists of determining the degree of support of being the same person or not. This decision is based on the analysis of some criteria assessing the skull-face morphological correspondence through the resulting skull-face overlay. In this work, we take a first step to design a decision support system for craniofacial superimposition. To do so, we consider the modeling of two of the most discriminative criteria for assessing craniofacial correspondence: the morphological and spatial relationship between the bony and facial chin, and the relative position of the orbits and the eyeballs. For each criterion, different computer vision-based approaches have been studied. The accuracy of each method has been calculated as its capability to discriminate in a cross-comparison identification scenario. Sugeno integral has been used to aggregate the results of the different methods taking into account the corresponding individual accuracy index. This allows us to provide a single global output specifying the matching of each criterion while combining the capabilities of different methods. Finally, the performance of the designed criteria and methods have been tested on 172 skull-face overlay problem instances of positive and negative cases to illustrate the discriminative power of each criterion. It has been shown that thanks to the use of Sugeno integral for aggregating different methods, a more robust measurement output is achieved.
... Forensic anthropologists have focused their attention on determining the identity of a missing person when skeletal information becomes the last resort for the forensic assessment [1][2]. Craniofacial superimposition (CFS) [1], one of the approaches in craniofacial identification [4][5], involves the superimposition of an image of a skull (or a skull model) with a number of ante mortem images of an individual and the analysis of their morphological correspondence. ...
Article
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As part of the scientific tasks coordinated throughout The 'New Methodologies and Protocols of Forensic Identification by Craniofacial Superimposition (MEPROCS)' project, the current study aims to analyse the performance of a diverse set of CFS methodologies and the corresponding technical approaches when dealing with a common dataset of real-world cases. Thus, a multiple-lab study on craniofacial superimposition has been carried out for the first time. In particular, 26 participants from 17 different institutions in 13 countries were asked to deal with 14 identification scenarios, some of them involving the comparison of multiple candidates and unknown skulls. In total, 60 craniofacial superimposition problems divided in two set of females and males. Each participant follow her/his own methodology and employed her/his particular technological means. For each single case they were asked to report the final identification decision (either positive or negative) along with the rationale supporting the decision and at least one image illustrating the overlay/superimposition outcome. This study is expected to provide important insights to better understand the most convenient characteristics of every method included in this study. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
... Forensic anthropologists have focused their attention on determining the identity of a missing person when skeletal information becomes the last resort for the forensic assessment [1][2]. Craniofacial superimposition (CFS) [1], one of the approaches in craniofacial identification [4][5], involves the superimposition of an image of a skull (or a skull model) with a number of ante mortem images of an individual and the analysis of their morphological correspondence. ...
... 5a. Przybliżenia wyglądu twarzy ze względu na swoją arbitralność nie mogą być uznane za wiarygodną metodę identyfi kacji (Stephan, Henneberg 2001), co wynika przede wszystkim z tego, że wielu cech, na które zwracamy uwagę przy identyfi kacji osób, nie da się skutecznie odtworzyć na podstawie czaszki (Stephan 2009;Stephan, Henneberg 2006;George 1993;por. Sołtysiak, Kozłowski 2009). ...
... Craniofacial superimposition (CS) [1,2,3] is a forensic process where photographs or video shots of a missing person are compared with the skull that is found. By projecting both photographs on top of each other (or, even better, matching a scanned three-dimensional skull model against the face photo/series of video shots), the forensic anthropologist can try to establish whether that is the same person. ...
... Anthropologists have focused their attention on determining the identity of a missing person when skeletal information becomes the last resort for the forensic assessment [1,2] . Craniofacial superimposition (CFS) [3], one of the approaches in craniofacial identification [4,5], involves the superimposition of a skull (or a skull model) with a number of ante mortem images of an individual and the analysis of their morphological correspondence. Since the first documented use of CFS for identification purposes [6] the technique has been under continuous improvement . ...
Article
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Craniofacial superimposition can provide evidence to support that some human skeletal remains belong or not to a missing person. It involves the process of overlaying a skull with a number of ante mortem images of an individual and the analysis of their morphological correspondence. Within the craniofacial superimposition process, the skull-face overlay stage just focuses on achieving the best possible overlay of the skull and a single ante mortem image of the suspect. Although craniofacial superimposition has been in use for over a century, skull-face overlay is still applied by means of a trial-and-error approach without an automatic method. Practitioners finish the process once they consider that a good enough overlay has been attained. Hence, skull-face overlay is a very challenging, subjective, error prone, and time consuming part of the whole process. Though the numerical assessment of the method quality has not been achieved yet, computer vision and soft computing arise as powerful tools to automate it, dramatically reducing the time taken by the expert and obtaining an unbiased overlay result. In this manuscript, we justify and analyze the use of these techniques to properly model the skull-face overlay problem. We also present the automatic technical procedure we have developed using these computational methods and show the four overlays obtained in two craniofacial superimposition cases. This automatic procedure can be thus considered as a tool to aid forensic anthropologists to develop the skull-face overlay, automating and avoiding subjectivity of the most tedious task within craniofacial superimposition.
... Anthropologists have focused their attention on determining the identity of a missing person when skeletal information becomes the last resort for the forensic assessment [1,2]. Craniofacial superimposition (CFS) [3], one of the approaches in craniofacial identification [4,5], involves the superimposition of a skull (or a skull model) with a number of antemortem images of an individual and the analysis of their morphological correspondence. ...
Article
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Objective, and unbiased validation studies over a significant number of cases are required to get a more solid picture on Craniofacial Superimposition reliability. It will not be possible to compare the performance of existing and upcoming methods for Craniofacial Superimposition without a common forensic database available for research community. Skull-face overlay is a key task within Craniofacial Superimposition that has a direct influence on the subsequent task devoted to evaluate the skull-face relationships. In this work, we present the procedure to create for the first time such a data set. We have also created a database with 19 skull-face overlay cases for which we are trying to overcome legal issues that allow us to make it public. The quantitative analysis made in the segmentation and registration stages, together with the visual assessment of the 19 face-to-face overlays, allow us to conclude that the results can be considered as a gold standard. With such a ground truth dataset a new horizon is opened for the development of new automatic methods whose performance could be now objectively measured and compared against previous and future proposals. Additionally, other uses are expected to be explored to better understand the visual evaluation process of craniofacial relationships in craniofacial identification. It could be very useful also as a starting point for further studies on the prediction of the resulting facial morphology after corrective or reconstructive interventionism in maxillo-facial surgery.
... The study of facial morphology from photographs has produced a great interest in forensic anthropology over the years [5]. The analysis of the anthropometric landmarks to define dimensions, proportions, and facial characteristics from photographs has been considered in diverse forensic areas such as identification of living individuals [19], age estimation [10], or craniofacial identification [1,23]. ...
Article
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The morphological assessment of facial features using photographs has played an important role in forensic anthropology. The analysis of anthropometric landmarks for determining facial dimensions and angles has been considered in diverse forensic areas. Hence, the quantification of the error associated to the location of facial landmarks seems to be necessary when photographs become a key element of the forensic procedure. In this work, we statistically evaluate the inter- and intra-observer dispersions related to the facial landmark identification on photographs. In the inter-observer experiment, a set of 18 facial landmarks was provided to 39 operators. They were requested to mark only those that they could precisely place on 10 photographs with different poses (frontal, oblique, and lateral views). The frequency of landmark location was studied together with their dispersion. Regarding the intra-observer evaluation, three participants identified 13 facial points on five photographs classified in the frontal and oblique views. Each landmark location was repeated five times at intervals of at least 24 h. The frequency results reveal that glabella, nasion, subnasale, labiale superius, and pogonion obtained the highest location frequency in the three image categories. On the contrary, the lowest rate corresponds to labiale inferius and menton. Meanwhile, zygia, gonia, and gnathion were significantly more difficult to locate than other facial landmarks. They produced a significant effect on the dispersion depending on the pose of the image where they were placed, regardless of the type of observer that positioned them. In particular, zygia and gonia presented a statistically greater variation in the three image poses, while the location of gnathion is less precise in oblique view photographs. Hence, our findings suggest that the latter landmarks tend to be highly variable when determining their exact position.
... Once the sample of candidates for identification is constrained by these preliminary studies, a specific identification technique is applied. Among those available in the discipline, craniofacial superimposition (Iscan, 1993;Krogman & Iscan, 1986;Stephan, 2009) is a forensic process where photographs or video shots of a missing person are compared with the skull that is found. By projecting both photographs on top of each other (or, even better, matching a scanned three-dimensional skull model against the face photo/series of video shots), the forensic anthropologist can try to establish whether that is the same person. ...
Article
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Craniofacial superimposition is a forensic identification technique where photographs or video shots of a missing person are compared with a skull found in order to determine whether that is the same person. The second stage of this complex forensic process, named skull-face overlay, aims to achieve the best overlay of the skull 3D model and the 2D image of the face. In this paper, we aim to propose a new skull-face overlay method based on the scatter search evolutionary algorithm. This new design exploits problem-specific information in order to achieve faster and more robust solutions. The performance of our proposal is compared to the current best performing approach in the field of automatic skull-face overlay. Results on six real-world identification cases previously solved by the Physical anthropology lab at the University of Granada (Spain) are considered in our experimental study. The proposed method has shown a very accurate and robust performance when solving the latter six face-skull overlay problem instances.
... Among them, craniofacial superimposition (CS) is the most relevant technique (Krogman and Iscan 1986;Iscan 1993;Taylor and Brown 1998;Stephan 2009). This method aims to compare photographs of a ''missing person'' with a skull by superimposing photographs of the skull and of the missing person to establish whether they are same person by matching anthropological landmarks defined in the literature (Martin and Saller 1966). ...
Article
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One of the most important tasks in forensic anthropology is human identification. Over the past decades, forensic anthropologists have focused on improving techniques to increase the accuracy of identification. Following a thorough examination of unidentified human remains, the investigator chooses a specific identification technique to be applied, depending on the availability of ante mortem and post mortem data. Craniofacial superimposition is a forensic process in which photographs of a missing person are compared with a skull in order to determine whether is the individual depicted and the skeletal remains are the same person. After more than one century of development, craniofacial superimposition has become an interdisciplinary research field where computer science has acquired a key role as a complement of forensic sciences. Moreover, the availability of new digital equipment has resulted in a significant advance in the applicability of this forensic identification technique. In this paper, we review a semi-automatic method devised to assist the forensic anthropologist in the identification process using craniofacial superimposition. The technique is based on a three-stage methodology. The first two are performed automatically by soft computing techniques. However, the final decision corresponds to the forensic expert. The performance of the proposed method is illustrated using several real-world identification cases.
Article
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Linear measurements taken from bony landmarks are often utilised in facial approximation (FA) to estimate and plan the placement of overlying soft tissue features. This process similarly guides craniofacial superimposition (CFS) practices. Knowledge of how hard and soft tissue features spatially relate around the mouth region is, however, limited. Geometric morphometric techniques have thus been used to investigate size and shape variation in dentition-to-lip mouth morphology in a South African population. Twenty landmarks (twelve dentition, eight lips) were digitised, using cone-beam CT images of the anterior craniofacial complex in a Frankfurt/Frankfort position, for 147 individuals aged between 20 and 75 years. Principal Component Analysis and Canonical Variate Analysis established that much shape variation exists. A two-way ANOVA identified significant (p < 0.0001) population and sex variation with mouth shape. Black individuals presented with thicker lips, with the oral fissure aligning closely to the dental occlusion. Oral fissure position for white individuals corresponded to the inferior one-quarter (females) or one-sixth (males) of the maxillary central incisor crowns. Males presented larger dimensions than females, but females had a greater lip-to-teeth height ratio than their male counterparts. A pooled within-group regression analysis assessed the effect of age on the dentition and lips and found that it had a significant (p < 0.0001) impact on mouth shape. Ageing was associated with a reduced lip and teeth height, increased mouth width, and a lowered oral fissure and cheilion placement. The generated mean shape data, with metric guides, offer a visual and numerical guide that builds on existing FA and CFS standards, enhancing our understanding of hard and soft tissue relationships.
Article
Subject-to-camera distance (SCD) is widely acknowledged to be a critical variable in craniofacial superimposition, but in practice it has been notoriously difficult to estimate from facial photographs. The recently proposed PerspectiveX algorithm offers the first potential capability to objectively undertake this estimation using quantified data. In this study, we test PerspectiveX’s legitimacy first by determining if the palpebral fissure length that it uses, falls in the relative-parallel-zone of the face (RPZ) where perspective distortion effects are minimal, thereby justifying its use for craniofacial superimposition (Study 1). Secondly, we validation test the PerspectiveX algorithm by using facial photographs acquired at known, whole meter ground truth distances between 1 and 10 m (Study 2). For study 1, we used 3D face scans to quantitatively map the relative parallel zone (RPZ) in 30 upright living subjects. For study 2, we used 2D facial photographs of up to 50 subjects at known 1 m interval distances. Results show the RPZ to cover a very thin vertical area of the face, but one that includes the palpebral fissure and the eyelids. This justifies the use of the palpebral fissure length in PerspectiveX. When tested using photographs taken at known distances, PerspectiveX performed with a signed mean and mean absolute error of 3.8% and 6.8% respectively for two prime lenses (85 and 100 mm). For a zoom lens operated at its extremes of 24 and 105 mm focal-lengths, PerspectiveX performed with a signed mean and mean absolute error of 4.4% and 11.0%, respectively. These errors are small in the superimposition context, translating into less than 1% difference in vertical face height. This supports the use of PerspectiveX in superimposition to objectively set the skull-to-camera distance, such that it replicates the face-to-camera distance to provide optically valid 1:1 comparisons of skulls and faces.
Article
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It is possible to see the effect of technology in every field in the developing and changing world. Technological developments have also affected Forensic Sciences and advanced the methods used in this field. Forensic Scientists work to solve forensic cases in the most accurate way through multidisciplinary studies. Especially the field of Forensic Anthropology appears as a discipline where more reliable determinations are made in the light of technological developments and contributes a lot to forensic investigations. The main study of Forensic Anthropology is identification. Identification is performed from skeletal remains or soft tissue samples. Forensic Anthropologists determine factors such as gender, age, ethnicity, causes of death reflected on the skeleton and teeth, and various distinctive features through bone remains. Forensic Anthropologists take on more and more important tasks in finding answers to the "who" and "how" questions that form the basis of forensic cases. New studies for identification have brought new methods with the effect of technology. These developments, which basically include computer imaging, mathematical algorithms and new imaging methods, have brought new perspectives to Forensic Anthropology. 3D imaging, X-ray use, CT scans and Lodox imaging are examples of these studies. By using these methods, anthropology studies have been brought to the virtual dimension. Thus, more accurate and clear results have begun to be obtained in identification studies.
Chapter
Forensic craniofacial identification encompasses the practices of forensic facial approximation (aka facial reconstruction) and craniofacial superimposition within the field of forensic art in the United States. Training in forensic facial approximation methods historically has used plaster copies, high-cost commercially molded skulls, and photographs. Despite the increased accessibility of computed tomography (CT) and the numerous studies utilizing CT data to better inform facial approximation methods, 3D CT data have not yet been widely used to produce interactive resources or reference catalogs aimed at forensic art practitioner use or method standardization. There are many free, open-source 3D software packages that allow engagement in immersive studies of the relationships between the craniofacial skeleton and facial features and facilitate collaboration between researchers and practitioners. 3D CT software, in particular, allows the bone and soft tissue to be visualized simultaneously with tools such as transparency, clipping, and volume rendering of underlying tissues, allowing for more accurate analyses of bone to soft tissue relationships. Analyses and visualization of 3D CT data can not only facilitate basic research into facial variation and anatomical relationships relevant for reconstructions but can also lead to improved facial reconstruction guidelines. Further, skull and face surface models exported in digital 3D formats allow for 3D printing of custom reference models and novel training materials and modalities for practitioners. This chapter outlines the 3D resources that can be built from CT data for forensic craniofacial identification methods, including how to view 3D craniofacial CT data and modify surface models for 3D printing.
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INTRODUCTION: The South African Police Service frequently relies on craniofacial approximation and superimposition to assist in identifying unknown deceased individuals. Standards to estimate lip height are however limited. Findings from this study share medical applications. Aims and objectives: Establish reliable standards for estimating lip height using dentoskeletal measurements. METHODS: Cone-beam CTs comprising 124 black and 39 white southern African adults were assessed. A series of dimensions were recorded using a DICOM viewer with an inbuilt measuring tool. Relationships between hard tissue structures (maxillary, mandibular and total central incisor heights, their corresponding root lengths, face height (N-Gn), and nose height (N-Sn)) and respective overlaying soft tissues (upper, lower and total lip heights) were evaluated. RESULTS AND CONCLUSIONS: Statistically significant differences were observed between population, sex and age groups. A selection of regression equations to estimate lip height was calculated that included population, sex and approximate age (20-39 and 40+ years) for improved goodness-of-fit (r²-value). Regression models using face height produced the strongest multiple correlation (r-value) and goodness-of-fit (r²-value). Validation testing indicated that regression models often improved upon mean measurements, while offering a degree of individuality that mean values do not.
Chapter
Traditionally, methodology within forensic anthropology has involved very basic techniques of measurement, observation and interpretation. Rooted in the academic fields of anatomy and physical anthropology, forensic anthropology has grown to address problems of recovery, determination of species, estimation of age at death, sex, ancestry, stature, postmortem interval, and the evaluation of evidence relating to foul play and identification. Growth and expansion of the field into new areas of application have revealed new problems needing new methodological solutions. Striving to resolve these problems, anthropologists have turned to new technology, or approaches utilized in related academic areas that would be new to anthropology. This chapter explores aspects of those technological developments and how they have found a home in the practice of forensic anthropology.
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This paper represents the first survey on the application of AI techniques for the analysis of biomedical images with forensic human identification purposes. Human identification is of great relevance in today’s society and, in particular, in medico-legal contexts. As consequence, all technological advances that are introduced in this field can contribute to the increasing necessity for accurate and robust tools that allow for establishing and verifying human identity. We first describe the importance and applicability of forensic anthropology in many identification scenarios. Later, we present the main trends related to the application of computer vision, machine learning and soft computing techniques to the estimation of the biological profile, the identification through comparative radiography and craniofacial superimposition, traumatism and pathology analysis, as well as facial reconstruction. The potentialities and limitations of the employed approaches are described, and we conclude with a discussion about methodological issues and future research.
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Craniofacial superimposition is a technique used in the field of forensic anthropology to assist in the analysis of an unknown skull. The process involves superimposing an image of the recovered skull over an ante mortem image of the suspected individual. In the past two decades, there has been a decline in the application due to the development of molecular analysis as a more precise and accurate identification technique. Despite its decrease in use, there has been significant development in superimposition techniques in the past five years, specifically to standardize procedures. One project, MEPROCS (The New Methodologies and Protocols of Forensic Identification by Craniofacial Superimposition), has attempted to establish a framework for solving the problems of past superimposition techniques. Future researchers should consider integrating information gleaned from clinical practices with the statistical and technical advances of craniofacial superimposition for better facilitating its use in forensic anthropology. Keywords: Forensic science, Anthropology, Craniofacial superimposition
Article
Forensic anthropology represents a dynamic and rapidly evolving complex discipline within anthropology and forensic science. Academic roots extend back to early European anatomists but development coalesced in the Americas through high-profile court testimony, assemblage of documented collections and focused research. Formation of the anthropology section of the American Academy of Forensic Sciences in 1972, the American Board of Forensic Anthropology in 1977/1978 and other organizational advances provided important stimuli for progress. While early pioneers concentrated on analysis of skeletonized human remains, applications today have expanded to include complex methods of search and recovery, the biomechanics of trauma interpretation, isotopic analysis related to diet and region of origin, age estimation of the living and issues related to humanitarian and human rights investigations.
Article
The overlay of a skull and a face image for identification purposes requires similar subject-to-camera distances (SCD) to be used at both photographic sessions so that differences in perspective do not compromise the anatomical comparisons. As the facial photograph is the reference standard, it is crucial to determine its SCD first and apply this value to photography of the skull. So far, such a method for estimating the SCD has been elusive (some say impossible), compromising the technical validity of the superimposition procedure. This paper tests the feasibility of using the palpebral fissure length and a well-established photographic algorithm to accurately estimate the SCD from the facial photograph. Recordings at known SCD across a 1-10 m range (repeated under two test conditions) demonstrate that the newly formulated method works: a mean SCD estimation error of 7% that translates into <1% perspective distortion error between estimated and actual conditions.
Chapter
Facial approximation is used to predict a face from a skull. The method helps draw public attention to cases involving skeletal remains and/or prompts recognition of the deceased individual when the predicted face is advertised in the media. Facial approximations may be conducted manually or using computers. The former approach is widely considered to be highly subjective and current capabilities of the method, for facial recognition, are hotly debated. This article provides an overview of the facial approximation technique and some of its latest, verified, soft tissue prediction methods.
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Despite the current use of radiography for quantifying sagittal skeletal measurements, it is an unsuitable way for screening or epidemiologic purposes. Although not fully approved, anthropometric measurements have been suggested as a substitute, and considering displacement of soft tissues, could possibly lead to more consistent results. The purpose of this study was to evaluate the reliability of anthropometric anteroposterior facial measurements under soft tissue compression using a special ruler. Anthropometric measurements were done with a specifically designed sliding ruler twice on 36 adult patients with a 14 day lag between two measurements. The ruler measured the distance between the external acoustic meatus and the nasion (Na), subnasal (Sn) point and the soft tissue pogonion (Pog). The soft tissue was displaced during measurements only to the extent that the underlying hard tissue resistance was felt subjectively by each assessor. The intraclass correlation coefficient (ICC) was calculated for both inter- and intra- rater measurements using SPSS software. All measurements had inter- and intrarater agreements above 0.9, with only a few parameters having lower bound confidence intervals below 0.9, but more than 0.8. Sagittal facial anthropometric measurements under soft tissue displacement using the specific ruler are valid and reliable and could possibly aid orthodontists in chairside craniofacial assessments.
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