Cranio-facial morphanalysis: a new method for enhancing reliability while identifying skulls by photo superimposition

Skull-photograph superimposition continues to be the most prevalent method employed for identifying a skull recovered in a criminal case as that belonging to a putative victim whose face photograph is available. The reliability of identification achieved has been shown to be 91%, indicating the possibility of a skull mismatching with a face photograph belonging to a person other than the actual deceased. This lack of reliability dampens the confidence of the expert and in turn confounds the mind of the judge. It has been shown that the variations in the shape of the facial organs are influenced by the corresponding variations in the skeletal elements of the facial skull. "Cranio-facial morphanalysis", a new anthroposcopic method proposed here for evaluating the shape correlations between a skull and a face photograph, when applied conjointly with skull-photograph superimposition is shown to increase the reliability in forensic skull identification.     

中国汉族成人颅骨CT片同一认定方法的研究

目的建立对中国汉族成人颅骨CT片进行同一认定的方法。方法按照纳入标准收集100例中国汉族成人颅骨CT片，对确定的识别指标进行观察和测量，对各指标的观测结果进行分类编码，然后按观测顺序编制特异的12位颅骨CT片识别编码。运用SPSS13．0统计学软件对所得数据进行各指标年龄和性别差异的统计学分析，利用个人识别能力公式计算单个指标和总体指标的个人识别能力。结果12项识别指标中有6个指标存在男女性别差异；12项指标累计个人识别能力可达到99．9997997％。结论本文确定中国汉族成人颅骨CT片12项观测指标，利用指标分类编码法可进行中国汉族成人颅骨CT片的同一认定。     

Identification of skull from its suture pattern

The examination of 320 skulls collected at random revealed that the ectocranial suture patterns in them are highly individualistic and that no two skulls can ever have an identical pattern. The possibility of these suture patterns being recorded incidentally in routine diagnostic skull radiographs was verified by examining the skull skiagrams preserved in radiology departments. A positive method of identification of the skull is suggested by the comparison of radiographic with visible skull suture pattern.     

Application of superimposition-based personal identification using skull computed tomography images

Superimposition has been applied to skulls of unidentified skeletonized corpses as a personal identification method. The current method involves layering of a skull and a facial image of a suspected person and thus requires a real skeletonized skull. In this study, we scanned skulls of skeletonized corpses by computed tomography (CT), reconstructed three-dimensional (3D) images of skulls from the CT images, and superimposed the 3D images with facial images of the corresponding persons taken in their lives. Superimposition using 3D-reconstructed skull images demonstrated, as did superimposition using real skulls, an adequate degree of morphological consistency between the 3D-reconstructed skulls and persons in the facial images. Three-dimensional skull images reconstructed from CT images can be saved as data files and the use of these images in superimposition is effective for personal identification of unidentified bodies.     

Improved skull identification using the superprojection technique with the help of a video-tape system (author's transl)

The photographic identification of a skull through the well-known superprojection technique can be modified and decisively improved by the use of a video-tape system. The identification method based on electronic photo composition is methodically simple to use. It offers the examiner the possibility to recognize the relationship between bone and soft part proportions, and the structure of the bone surface and the details of the soft part shape, as a concrete, tangible characteristic of identity to a substantially greater extent. The large number of controllable characteristics inherent in the ihgh degree of individuality of the skull offers not just an either/or "The skull fits"/ "It does not fit" into a photograph, but achieves proof of disproof of identity.     

Methods of making the plaster copies of skulls for the medical and criminalistic identification of individuals

A possibility was studied to use the plaster copies of skulls in the forensic medical identification of personality by applying the craniofacial method. No dependence was found between the plaster casts and the moulding types. Differences between the same craniometric sizes in the skull and in its cast are of an incidental nature. Such incidental deviation is related with an accuracy of determining the localization of craniometric points and with an instrumental precision of measuring devices. The necessity is substantiated that, while making a craniofacial examination, it is necessary to mark all anthropometric points in the skull cast, with the original being a control. The use of a plaster skull cast is possible in those cases, when the burial of the remains must be done in full.     

Identification of the cadaver remains of Josef Mengele

In 1985 at the cemetery in Embu near Sao Paulo, Brazil, parts of a skeleton were exhumed, and now these parts have been examined to determine whether they are the remains of the corpse of Dr. Josef Mengele, the camp doctor of the Auschwitz concentration camp. The osteometrical and osteological findings ascertained correspond completely and consistently without contradiction with all the available personal data of Josef Mengele. Through a method of electronic visual mixing for the identification of the skull, it was determined that all the authentic pictures available used for comparison correspond definitely and consistently to the exhumed skull.     

Reliability of Craniofacial Superimposition Using Three‐Dimension Skull Model

Craniofacial superimposition is a technique potentially useful for the identification of unidentified human remains if a photo of the missing person is available. We have tested the reliability of the 2D‐3D computer‐aided nonautomatic superimposition techniques. Three‐dimension laser scans of five skulls and ten photographs were overlaid with an imaging software. The resulting superimpositions were evaluated using three methods: craniofacial landmarks, morphological features, and a combination of the two. A 3D model of each skull without its mandible was tested for superimposition; we also evaluated whether separating skulls by sex would increase correct identifications. Results show that the landmark method employing the entire skull is the more reliable one (5/5 correct identifications, 40% false positives [FP]), regardless of sex. However, the persistence of a high percentage of FP in all the methods evaluated indicates that these methods are unreliable for positive identification although the landmark‐only method could be useful for exclusion.     

Use of Craniofacial Superimposition in Historic Investigation

A skeleton discovered in Grand Forks, North Dakota was purported to belong to Clelland “Clell” Miller, a James‐Younger gang member, who was killed during the Northfield Bank robbery on September 7, 1876. A 3‐D image from a computer tomography (CT) scan of the skull was obtained, and a craniofacial superimposition was conducted to determine if the skull could belong to Miller. The superimposition method used in this case was to overlay the CT image of the skull onto Miller's postmortem photograph. In addition to the craniofacial superimposition, the images were juxtaposed to compare similarities or differences in facial morphology between the skull and photograph. Superimposition methods can be used to exclude identifications; however, they should not be used as a conclusive method for identification. In this case, there were sufficient similarities between the skull and Miller's photograph; therefore, the skull could not be eliminated as possibly being that of Miller.     

Identification of the cadaveric remains of Josef Mengele

In 1985 at the cemetery in Embu near Sao Paulo, Brazil, parts of a skeleton were exhumed, and now these parts have been examined in order to determine whether they are the remains of the corpse of Dr. Josef Mengele, the camp doctor of the Auschwitz Concentration Camp. The osteometrical and osteological findings ascertained correspond completely and consistently without contradiction with all the available personal data of Josef Mengele. Through a method of electronic visual mixing for the identification of the skull, it was determined that all the authentic pictures available used for comparison correspond definitely and consistently in all details to the exhumed skull.     

Computer-assisted skull identification system using video superimposition

This system consists of two main units, namely a video superimposition system and a computer-assisted skull identification system. The video superimposition system is comprised of the following five parts: a skull-positioning box having a monochrome CCD camera, a photo-stand having a color CCD camera, a video image mixing device, a TV monitor and a videotape recorder. The computer-assisted skull identification system is composed of a host computer including our original application software, a film recorder and a color printer. After the determination of the orientation and size of the skull to those of the facial photograph using the video superimposition system, the skull and facial photograph images are digitized and stored within the computer, and then both digitized images are superimposed on the monitor. For the assessment of anatomical consistency between the digitized skull and face, the distance between the landmarks and the thickness of soft tissue of the anthropometrical points are semi-automatically measured on the monitor. The wipe images facilitates the comparison of positional relationships between the digitized skull and face. The software includes the polynomial functions and Fourier harmonic analysis for evaluating the match of the outline such as the forehead and mandibular line in both the digitized images.     

Computer-aided personality identification by skull and life-time photography by POSKID 1.1 method

An improved method for computer-aided personality identification by the skull, based on the POSKID 1.1 software, consists in investigation of enlarged images of the skull and life-time photograph of the probable individual by coordinates of 49 anatomical points; independent quantitative evaluation of the aspect of each of the compared objects by the X, Y, and Z axes; formal evaluation of the results of comparative study of the skull-portrait by multidimensional discriminant analysis models. The proposed version differs from the POSKID 1.0 software in the method for evaluating the spatial position of the head on the portrait and adequate orientation of the skull in space, which necessitates the utilization of coordinate-regulated holder POSKID 1.1 method is based on multidimensional discriminant analysis and suggests a virtually reliable solution in 76.13-80.65% cases, a probable solution (positive and negative) in 11.61-18.06% cases, and motivated refusal from solution in 5.81-7.74% cases. In case of a probable or indefinite solution further investigations are recommended making use of life-time photographs with different aspects.     

Skull-photo superimposition and border deaths: identification through exclusion and the failure to exclude

We report on the application of video skull-photo superimposition as an identification method in a case from Ajo, Arizona in which five individuals died after crossing into southern Arizona from Mexico. Initial analyses at the Pima County Forensic Science Center in Tucson, Arizona determined that the disarticulated skeletal remains represented two adult Hispanic males and three adult Hispanic females. Based on biological profiles, both the males and one of the females were tentatively identified and assigned names. The other two females were too similar in age and height, making skeletal separation and identification difficult. As a result, the Michigan State University Forensic Anthropology Laboratory assisted in the identification efforts by performing video skull-photo superimposition on the two unknown females. The skulls were compared to a photograph reported to be one of the missing females. By evaluating facial proportionality and by comparing a number of morphological features of the face and skulls, one skull was excluded as a possible match and one skull was not excluded as a match to the antemortem photo. Because this case was presumed to be a closed disaster, the exclusion of one skull and the failure to exclude the other represented circumstantial identifications.     

A novel skull registration based on global and local deformations for craniofacial reconstruction

Craniofacial reconstruction is important in forensic identification. It aims to estimate a facial appearance for human skeletal remains using the relationship between the soft tissue and the underlying bone structure. Various computerized methods have been developed in recent decades. An effective way is to deform a reference skull to the discovered skull, and then apply the same deformation to the skin associated with the reference skull to provide an approximate face for the discovered skull. For this method, the better the two skulls match each other, the more face-like the reconstructed skin surface will be. In this paper, we present a novel skull registration method that can match the two skulls closely, so as to improve the accuracy of the reconstruction. It combines both global and local deformations. A generic thin-plate spline (TPS)-based deformation, which is global, is applied first to roughly align the two skulls based on two groups of manually defined landmarks. Afterwards, the two skulls are largely matched, except some regions, on which some new landmarks are automatically marked. A compact support radial basis functions (CSRBF)-based deformation, which is local, will then be performed on these regions to adjust the initial alignment of the two skulls. Such adjustment can be repeatedly implemented until the two skulls have optimal alignment. In addition, all the skulls and face involved in the registration are represented by their single outer surfaces to facilitate the reconstruction procedure. The experiments demonstrate that our method can create a plausible face even when the reference skull is very different from the discovered skull. As a result, we can make full use of our database to provide multiple estimates for a principle components analysis (PCA) for the final reconstruction.     

A methodology for near-optimal computational superimposition of two-dimensional digital facial photographs and three-dimensional cranial surface meshes

The authors present a methodology for human identification based on digital superimposition techniques. This methodology computes a fast, near optimal fit between a three-dimensional skull surface mesh and a two-dimensional digitized facial photograph. Since this is done digitally, (1) the photograph can be enhanced to reduce or eliminate motion blur, overexposure or underexposure, and out-of-focus distortions; (2) previous problems with skull/photograph scaling and alignment are minimized or eliminated; and (3) the photograph and skull can be numerically correlated. Two of several test cases produced from an implementation of this methodology are also presented.     

3D forensic facial approximation: Implementation protocol in a forensic activity

The primary objective of this paper is to report on the successful implementation of forensic facial approximation in a real case in the forensic context. A three‐dimensional (3D) facial approximation protocol of the skull was performed with free software, applying techniques in a virtual environment that have already been consolidated in the literature. The skull was scanned with the photogrammetry technique, the digital replica was imported in the Blender software (Blender Foundation, Amsterdam) and individualized model sketches of the face were traced with the MakeHuman software (MakeHuman Org) according to the anthropological profile of the victim. The face created was imported in Blender, where it was adapted, modeled, and sculpted on the 3D skull and its soft tissue markers, using an American open‐source application of the technique in the digital environment. The face created in a virtual environment was recognized and legal identification procedures were started, resulting in the more agile delivery of the disappeared body to its next of kin. It is therefore concluded that facial approximation may not be a primary method of human identification, but it can be satisfactorily applied in the forensic field as an individual recognition resource. It has great value in narrowing the search, reducing the number of alleged victims, and leading to identification tests, therefore significantly reducing the number of genetic DNA (deoxyribonucleic acid) tests—which are considered costly for the State or Federation—and consequently reducing the waiting time before delivery of the body to its family.     

Restoration of the fragmented skull in expert human identification

Restoration of fragmented skull in expert personality identification is attained by assembly of bone fragments, modeling of bone defects by means of special plastic, and mathematical prediction of the lacking craniometric parameters. The authors suggest 111 equations of multiple linear regression which can be used in restoration of fragmented cerebral and facial parts of the skull. Prediction of craniometric parameters is useful for control and correction of plastic restoration of the skull. Regression equations are the most efficient in cases when the mandible is absent or in defects of symmetrical right- and left-side fragments of the skull. All stages of restoration are illustrated with examples from expert practice.     

An unusual case of cranial image recognition

We encountered an unusual practical case of craniofacial identification recently. The peculiarity of the case was that the skull itself was not available for examination unlike other such common cases. The supplied material exhibits were, a nearly front view photograph of a skeletonized face and a front view face photograph of the suspected victim. Further, the condition of the skull during taking its photograph was such that its lower and the upper jaws were not in a normal closed condition. The procedure involved in dealing with such a complicated craniofacial identification problem would be quite interesting from a forensic investigator's point of view, since standard methods of skull identification like photo/video superimposition techniques were not at all applicable here. As such, the present case report provides the details of the multiphase procedure adapted by us in dealing with this abnormal case. A solution to this unprecedented craniofacial identification problem was worked out by appropriate exploration of a newly introduced digital image processing technique that is based on craniofacial symmetry perception. The procedure leads to the reconstruction of a superimposable cranial image with upper and lower teeth in normal closed condition for establishment of its identity in usual way.