Superimposition technique for skull identification with Afloat® software

Abstract

The craniofacial superimposition technique is still an important way of identifying skulls when there is no reference sample for a forensic DNA analysis, when DNA typing from remaining tissue samples has failed, or when antemortem dental records are not available. Through the widespread use of digital photography, the probability of portrait photographs of the missing person being available for comparison is reasonably high. We present a superimposition technique that is inexpensive, since it uses a free software tool compatible with the soft-and hardware components already being used in many facilities. Into the bargain, this technique yields high-quality results.

Modeling Facial Soft Tissue Thickness for Automatic Skull-Face Overlay

“…Our proposal goes beyond the use of tissue depth markers [22] as it directly incorporates the corresponding landmark spatial relationships and distances within the automatic SFO procedure (Fig. 2).…”

“…This novel proposal uses the same optimization mechanism employed before [9], [16] but it changes the formulation of the problem to directly incorporate the spatial relationships between corresponding landmarks. Unlike traditional SFO approaches locating tissue depth markers on the physical or the 3D model skull [20], [22], our proposal allows us to incorporate any soft tissue study easily.…”

Reliability of Craniofacial Superimposition Using Three‐Dimension Skull Model

“…Finally, from the second half of the 1980s superimposition was carried out with computers and so it has been called “ computer‐aided superimposition ”. This last methodology is divided into two categories: The “nonautomatic” one, if the computer is employed only as an interface and the superimposition (sizing and orientation of the images) is manually made by the operator, also with the help of commercial software ; the “automatic” one if the computer itself carries out the superimposition automatically finding the best orientation of images .…”

“…According to some authors, the craniofacial superimposition techniques can be useful to identify an unknown subject , especially if two or more photographs, taken from different points of view, are utilized , although the availability of several photos is a great limit for forensic cases. Whereas other authors think that it should be employed exclusively to exclude identity .…”

“… employ it as an excluding technique in a closed disaster; Birngruber et al. consider craniofacial superimposition an identification method on the same level of forensic odontostomatology and molecular genetics; Gordon and Steyn underline that it is accepted by the South African judicial system as a method to identify unknown individuals. Nevertheless, most of the authors state that superimposition should be performed in conjunction with other traditional identification techniques , because of its very low accuracy rates, and it should be conducted as the only identification method when the skull is the only unique part available and no other methods can be applied .…”