Facial Approximation and Craniofacial Superimposition

Stephan, Carl N.

doi:10.1007/978-1-4419-0465-2_149

Cited by 19 publications

(37 citation statements)

References 186 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Subject-to-camera distance is a major item of concern for craniofacial superimposition because it has the capability to change the appearance of objects in the field of view, undermining one-to-one anatomical comparisons of separately photographed skulls and faces [4][5][6][7][8][10][11][12]. Prior lack of consensus on and accounting for this variable has occurred because it has not been thoroughly documented across common SCD ranges (see e.g., Table 1).…”

Section: Discussionmentioning

confidence: 99%

“…That is, magnification is not the only issue at hand; differential scaling of the object within the photograph and edge visibility also count, as mentioned above [4,6,21]. Only when the face-to-camera distance is large, and perspective effects small (orthogonal views approximated), that a scaling factor can be safely applied to the skull photograph (which must also be taken at large SCD) to produce a picture that is comparable to the face photograph.…”

Section: Page 4 Of 31mentioning

confidence: 99%

“…At short subject-to-camera distances (SCD) it is well-known that the point projection of a 3D scene to a 2D plane in photography renders parts of objects closer to the lens of the camera larger than those positioned further away [1][2][3][4][5][6][7][8]. Point projection additionally causes false impressions of the true edges of 3D spherical objects, like a skull or a face, at short SCDs [1,3,4] (Fig.…”

Section: Introductionmentioning

confidence: 99%

“…Point projection additionally causes false impressions of the true edges of 3D spherical objects, like a skull or a face, at short SCDs [1,3,4] (Fig. 1 & 2).…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, camera perspective is very important to consider when photographs of skulls and faces are analysed (Fig. 3) because different SCDs between images, and/or position in the field of view, will prevent legitimate one-to-one comparisons of the craniofacial anatomy as sought by the superimposition procedure [4][5][6][7][8][10][11][12]. This has not been fully appreciated in the literature where validation studies often fail to report which SCDs were used [13][14][15], equipment is frequently designed without regard to SCD [16,17] and SCD generally goes under emphasized, e.g., "some effort should be made to replicate the camera distance" [18] p.385.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Perspective distortion in craniofacial superimposition: Logarithmic decay curves mapped mathematically and by practical experiment

Stephan

2015

Forensic Science International

Self Cite

View full text Add to dashboard Cite

The superimposition of a face photograph with that of a skull for identification purposes necessitates the use of comparable photographic parameters between the two image acquisition sessions, so that differences in optics and consequent recording of images does not thwart the morphological analysis. Widely divergent, but published, speculations about the thresholds at which perspective distortion becomes negligible (0.5 to >13.5 m) must be resolved and perspective distortion (PD) relationships quantified across their full range to judge tolerance levels, and the suitability of commonly employed contemporary equipment (e.g., 1 m photographic copy-stands). Herein, basic trigonometry is employed to map PD for two same sized 179 mm linear lengths -separated anteroposteriorly by 127 mm -as a function of subject-to-camera distance (SCD; 0.2 to 20 m). These lengths approximate basic craniofacial heights (e.g., tr-n) and widths (e.g., zy-zy), while the latter approximates facial depth (e.g., n-t). As anticipated, PD decayed in logarithmic and continuous manner with increasing SCD. At SCD of 12 m, the within-image PD was negligible (<1%). At <2.5 m SCD, it exceeded 5% and increased sharply as SCD decreased. Since life size images of skulls and faces are commonly employed for superimposition, a relative 1% perspective distortion difference is recommended as the ceiling standard for craniofacial comparison (translates into a ≤2 mm difference in physiognomical face height). Since superimposition depends on relative comparisons of a photographic pair (not one photograph), there is practically no scenario in superimposition casework where subject-to-camera distances should be ignored and no single distance at which PD should be considered negligible (even if one image holds >12 m subject-to-camera distance).

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Page 4 Of 31mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Point projection additionally causes false impressions of the true edges of 3D spherical objects, like a skull or a face, at short SCDs [1,3,4] (Fig. 1 & 2).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Perspective distortion in craniofacial superimposition: Logarithmic decay curves mapped mathematically and by practical experiment

Stephan

2015

Forensic Science International

Self Cite

View full text Add to dashboard Cite

show abstract

A history of forensic anthropology

Ubelaker

2018

American J Phys Anthropol

View full text Add to dashboard Cite

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.

show abstract

Evaluating sexual dimorphism in the human mastoid process: A viewpoint on the methodology

et al. 2015

View full text Add to dashboard Cite

The mastoid process is one of the most sexually dimorphic features in the human skull, and is therefore often used to identify the sex of skeletons. Numerous techniques for assessing variation in the size and shape of the mastoid process have been proposed and implemented in osteological research, but its complex form still presents difficulties for consistent and effective analysis. In this article, we compare the different techniques and variables that have been used to define, measure, and visually score sexual dimorphism in the mastoid process. We argue that the current protocols fail to capture the full morphological range of this bony projection, and suggest ways of improving and standardizing them, regarding both traditional and 3D-based approaches.

show abstract

Facial Approximation and Craniofacial Superimposition

Cited by 19 publications

References 186 publications

Perspective distortion in craniofacial superimposition: Logarithmic decay curves mapped mathematically and by practical experiment

Perspective distortion in craniofacial superimposition: Logarithmic decay curves mapped mathematically and by practical experiment

A history of forensic anthropology

Evaluating sexual dimorphism in the human mastoid process: A viewpoint on the methodology

Contact Info

Product

Resources

About