Facial reconstruction advances

Revolutionary advances in the science of facial reconstruction may soon make it much easier to identify missing people, including crime victims, when little more than a skull has been found.

Dr George Dias, a University of Otago senior lecturer in anatomy and structural biology, is excited by a series of recent developments which he believes will deliver huge benefits in forensic facial reconstruction within five years.

Dr Dias, who is part of a university forensic research group, said big advances were occurring both in the means of determining the individual characteristics of a person's face from their skull, and in the technology used to create a subsequent physical reconstruction of the head and face.

Working with Prof I.M.Premachandra, of the Otago department of finance and quantitative analysis, and who has neural network expertise, as well with other university colleagues, Dr Dias has recently used "a novel and more accurate method" to determine the soft tissue depths of the face.

"This is the first facial reconstruction done using this more accurate method anywhere in the world," he said.

"It's almost mind-boggling how it does it," he said of the new computerised neural network system.

A system of average tissue depths had long been used to create the facial likeness, but such averages did not sufficiently convey the individuality of the human face.

The neural network approach utilised a form of artificial intelligence which had been "trained" to generate specific tissue depths using more than 20 points on an individual skull.

A new and more accurate database of New Zealand facial tissue depths, developed by former Otago MSc student Charlotte Oskam, had also been used in the training.

Facial "approximation" methods were used when police had exhausted other means to identify human remains.

"Nobody should be buried as a John Doe or Joan Doe. Everybody should have the dignity of having a name," Dr Dias said.

The latest reconstruction had used computerised CT scan data obtained of a 2300-year-old skull, which forms part of an Egyptian mummy, long housed at the Otago Museum.

A Christchurch firm had used the CT data - which provides a series of electronic 3D "slices" through a skull or a body - to guide a rapid prototyping system in which several automated lasers had created, layer by layer, a closely accurate replica skull, made of resin.

From the replica skull, two plaster heads have been created, one of them offering a new facial likeness of a previously mysterious Egyptian woman, whose mummified body has been hidden under bandages.

This face will be revealed at the museum on January 28.