Masters Theses

Date of Award

12-1994

Degree Type

Thesis

Degree Name

Master of Arts

Major

Anthropology

Major Professor

William M. Bass

Committee Members

R.L. Jantz, Lyle W. Konigsberg

Abstract

This thesis outlines the examination and test of a method developed by the University College, London, Department of Medical Physics and Bioengineering for facial reconstruction using the latest technology in three dimensional laser imaging. The University College technique involves a skull on a rotating platform as the focal point of a laser beam fanned out into a straight line. A video camera placed obliquely to the skull records the distortions in the laser beam created by the surface contours. These distortions are recorded from two directions through the use of four surface-silvered mirrors which allows for the triangulation of all the points along the laser beam. As the skull rotates numerous points are measured in order to create a three dimensional computer image of the skull. In the second phase of the process, a living individual of comparable age, race, sex, and stature to the skull under examination is scanned using the same process. The two separate images are then combined to form a third which is assumed to represent a reconstructed image of the skeletal material.

Although the results of the faces that have been created by this method have thus far been successful, University College has not been able to conduct adequate testing of this process. This is largely due to the mainly historic nature of the subjects, and an inability to gain access to modern remains. This lack constitutes a possible flaw in what would otherwise be a highly beneficial system.

In order to conduct such tests, five skulls were used from the Anthropological Research Facility at the University of Tennessee, Knoxville that had been photographed prior to decomposition. A blind test of the system with a comparison of the final computer generated image to the individual's photograph would provide results that can confirm or reject the validity of the technique. The skepticism voiced over the use of the data taken from live individuals, specifically its combination with the remains to create the final image, has been shown to have grounds for concern.

Preliminary results indicate that both the use of older living subjects, with more prominent facial features (necessary due to the aged nature of the skeletal remains), and an over-weight subject provide problems with which the system has difficulty in coping. Also the use of a living subject with a facial expression creates a further feature for which the computer is unable to compensate. However, it is possible to instruct the system to produce a result using the more traditional skin depth measurement tables, as well as adding a program to enable the computer to 'average out' any distinct features of the living subject used. These aspects provide further avenues for experimentation and testing.

The implications of this system could be far reaching. If the accuracy of the technique can be enhanced then the potential for the method to provide a quick, realistic, and affordable image of a set of skeletal remains can be realized. In addition, this technique could provide a reliable and beneficial service to many law enforcement agencies. The somewhat negative results offer valuable information on which aspects of the system need to be revised. This factor is especially important because this technique is growing in popularity, and the accuracy of its methodology must continue to be assessed and improved.

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