The positioning and magnification of faces and skulls for photographic superimposition

In the identification of persons living or dead, or of skulls, the technique of photographic superimposition of laboratory images on existing original portraits has frequently been used. The applicability of the technique and the confidence in the results have always depended very much on the professional acceptance and experience of forensic specialists. Defined preconditions, improved methods and clear-cut directions on how to posture the head or the skull and how to magnify its photographic laboratory image, not only help to standardize and simplify procedures, but also increase the accuracy and credibility of the resulting diagnoses. A systematic approach with standard photographic equipment is presented. The validity of the results is discussed.     

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.     

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.     

Identification of dog bites using a comparative video analysis

Pictures from wounds are identified as bite marks of dogs with help of the video-comparison-technic. It is shown, that two dogs had left bite marks.     

Analysis of six Vietnamese trophy skulls

This report presents morphologic, metric, and contextual information on six documented trophy skull specimens confiscated from U.S. servicemen during the Vietnam War. Additional information on the history and occurrence of trophy skull collecting is provided. This sample, consisting mostly of young Vietnamese males, exhibits graffiti, painting, and other evidence of postmortem decorative modification. Identification of trophy skulls is important to medicolegal and anthropological researchers in distinguishing trophy remains from archaeological and forensic specimens.     

西南地区成人男性颅骨的相关回归分析

目的研究颅骨部分测量指标间的相关性,以期建立在对破损颅骨进行颅骨面貌复原时,利用尚存指标推断缺失指标的方法。方法用人体骨骼测量仪对41个男性颅骨的颅长、颅宽、颅高等14个指标进行测量,将测量值输入SPSS统计软件,找出相关性好的指标,建立各指标间相互推断的回归方程。结果部分测量指标间呈中度以上相关,应用逐步回归的方法得出回归方程24个,方差检验均具统计学意义(P<0.01)。结论本研究所建立的回归方程可为法医人类学和考古人类学的颅骨修复提供备选方法。     

Development of equipment for the standardization of skull photographs in personal identifications by photographic superimposition

The technique of photographic superimposition of postmortem specimens (dried skull or head) positioned identically to the orientation in an antemortem smiling photograph is now a recognized method for personal identification of human remains. Previous methods used to produce the postmortem photographs were problematic as orientation of the specimen could not be easily adjusted and positions were not reproducible. The objective of this paper is to describe the design and method of use of purpose-constructed equipment intended to alleviate these problems. The equipment comprises a skull-holding jig based conceptually on the Royal Berkshire Hospital halo frame. This is mounted on a pan-and-tilt device, incorporating calibrated measurement scales, enabling independent movements in each of the Cartesian coordinates. A camera is attached to an adjustable mount running on twin parallel rails allowing the camera-to-specimen distance to be varied. The equipment has proven to be straightforward in use and offers considerable advantages over previously described methods for producing postmortem photographs.     

Remote control skull positioning device for superimposition studies.

The success of the superimposition technique requires positioning the skull in the same posture of the face as seen in the given photograph. A scientific method for positioning the skull has already been proposed by Sekharan. This paper deals with the simple remote control tilt and rotatory device developed in the Forensic Sciences Department, Madras. A pan and tilt arrangement usually utilized in surveillance cameras and two a.c. servomotors, one to tilt the pan and the other to rotate the pan are used.     

Possiblities of craniofacial identification from incomplete and damaged skulls

With the aim of development criteria for assessment of results of personal identification with the use of the method of photo superposition of incomplete and damaged skulls at initial stages of our work, the frequency of submission of such skulls to examination was determined. Main groups of skull defects were determined, and identification results subject to each defect were estimated; which gave conclusion that presence or absence of one or another defect did not impede photo superposition. Signs, which most frequently were crucial for final result of identification, were determined. Analysis of obtained data show that the more number of crucial signs will be taken into account at personal identification, all the more with incomplete skulls, the more valid result will be obtained.     

The occurrence of Japanese trophy skulls in the United States

The skulls of two Japanese soldiers brought back to the United States following World War II suggest that more may be appearing in forensic science cases. Both cases are cranial vaults without faces or lower jaws. One was a fighter pilot. Both skulls have secondary characteristics of "dry house dust" adhering to the bone and have, to some degree, been painted.     

A study on the standard for forensic anthropologic identification of skull-image superimposition

By means of X-ray photography tests were made of 224 (100 males and 124 females) volunteer Chinese adults of Han nationality to study the related regular patterns of superimposed projection of face landmarks onto the skull. On the basis of these tests, the present article reveals from a forensic anthropology angle the related regular patterns of plane projection of the human face with its skull. Study shows that there exist a strict individual identity and exclusiveness in relation between the human face and skull. The related regularity of displacement of face landmarks appears in projection of the skull with the human head at different photographic positions and angles. On the basis of this discovery, 52 indexes in 4 groups were established as a standard for judging the identification of a skull's body origin by means of skull-image superimposition. Based on forensic anthropology, the technique has raised to a great extent the credibility of unknown skull identification. In the past 8 years, 89 unknown skulls have been identified with their body origins which provided important and accurate evidence for the solution of murders with dismembered bodies, skeletonized bodies, and unidentified dead bodies.     

Sex diagnosis of Chinese skulls using multiple stepwise discriminant function analysis.

Sixty Chinese skulls (30 males and 30 females) from Liaoning Province of the People's Republic of China were used in this study. Forty-one variables on each skull were measured and one group of 14 and a second group of 5 variables were selected from all the variables by applying multiple stepwise regression on a computer. Discriminant equations for the 14 and 5 variables for sex diagnosis have been obtained and these variables are highly significant. The discriminant rate for the group of 5 variables resulted in accurate sex determination in 96.7% of cases. For the group of 14 variables there was 100% success rate.     

Identification by MRI

A semi-skeletted water-lodged corpse was supposed to be an 82-year-old missed man. Fifteen years ago this person underwent an operation of a trimalleolar fracture of the left ankle joint. Conventional X-ray photograms of the left ankle joint of the water-lodged corpse showed no evidence of an operation. A T-1 weighted spin-echo sequence revealed the entire aspect of the osteosynthesis as documented in the previously performed post-operative X-ray photograms.     

Independent instances of "souvenir" Asian skulls from the Tampa Bay area

In the summer of 1984, police in Pinellas County, Florida, confiscated six identically colored imported Asian skulls (in a shipping case) from a private citizen. In May 1988, in nearby Hillsborough County, police confiscated a very similar skull from another private citizen, who allegedly had found it in an abandoned house. Aside from slight color differences between the six found in Pinellas County and the one found in Hillsborough County, the skulls are virtually identical in their osteological characteristics and condition and in the vital statistics derived from each. Each skull is as clean and dry as those typically sold by commercial scientific supply outlets in the United States. Each is edentulous (primarily premortem), between approximately 20 and 60 years of age at death, and morphologically Asian. Five of the seven are morphologically male, one is morphologically female, and one is a mosaic with respect to gender-related features. Police, medical examiners, coroners, and forensic anthropologists should be aware of such "souvenir" specimens, in the event that they encounter similar skulls. Discriminant function analyses for race and sex yield considerably conflicting results, which underscores the need for using extreme caution when interpreting forensic science estimates based on such techniques.     

An investigation into the accuracy and reliability of skull-photo superimposition in a South African sample

One of the aims of forensic science is to determine the identities of victims of crime. In some cases the investigators may have ideas as to the identities of the victims and in these situations, ante mortem photographs of the victims could be used in order to try and establish identity through skull-photo superimposition. The aim of this study was to evaluate the accuracy of a newly developed digital photographic superimposition technique on a South African sample of cadaver photographs and skulls. Forty facial photographs were selected and for each photo, 10 skulls (including the skull corresponding to the photo) were used for superimposition. The investigator did not know which of the 10 skulls corresponded to the photograph in question. The skulls were scanned 3-dimensionally, using a Cyberware? Model 3030 Colour-3D Scanhead scanner. The photos were also scanned. Superimposition was done in 3D Studio Max and involved a morphological superimposition, whereby a skull is superimposed over the photo and assessed for a morphological match. Superimposition using selected anatomical landmarks was also performed to assess the match. A total of 400 skull-photo superimpositions were carried out using the morphological assessment and another 400 using the anatomical landmarks. In 85% of cases the correct skull was included in the possible matches for a particular photo using morphological assessment. However, in all of these cases, between zero and three other skulls out of 10 possibilities could also match a specific photo. In the landmark based assessment, the correct skull was included in 80% of cases. Once again, however, between one and seven other skulls out of 10 possibilities also matched the photo. This indicates that skull-photo superimposition has limited use in the identification of human skeletal remains, but may be useful as an initial screening tool. Corroborative techniques should also be used in the identification process.     

Video superimposition at the C.A. Pound Laboratory 1987 to 1992.

William R. Maples practiced many aspects of human identification using simple and relatively inexpensive video superimposition equipment. Identification of skulls by comparison to known photographs was a primary concern. Clear, smiling photographs revealing the spatial relationships of the teeth to one another led to uncomplicated positive identifications. However, without benefit of dentition, how accurate was an identification based on the alignment of soft tissues with the underlying skull? Most importantly, how often would a false positive result when anterior dentition were not available? A study conducted by this author and Dr. Maples used three human heads and 98 profile and full-face photographs. A 0.6% incidence of false match resulted when both views of the face were used. Lateral view and frontal view superimpositions were identified incorrectly in 9.6% and 8.5% of the sample respectively. As a result, multiple photographs from varying angles were requested for superimposition identity cases. Additional applications in laboratory case work were developed for the equipment. Light boxes under the television cameras allowed radiographic comparisons. Video taped comparisons of antemortem and postmortem radiographs were shown to medical examiners and families as proof of identification. Dr. Maples and this author were also involved in several cases in which photographs taken by a surveillance or ATM camera were compared to court ordered photographs of an alleged perpetrator. One case, which went to trial, led to the conviction of a habitual criminal under Florida statute. This individual had a condition known as Stahl's ear, a deformation of the cartilaginous structure. The ear was seen clearly in many of the ATM camera photographs and was aligned easily with the known photographic sample.     

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 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.