All in the eyes: corneal reflections in photos can help solve crimes

Date: Dec-31-2013The eyes are not just the mirror of the soul, they also mirror the world around us. Now,

a UK team has found that today's high-resolution digital images are now so detailed, they can

enlarge the eyes in people's photos and retrieve images of out-of-shot bystanders reflected on

their corneas.

Combine this with the fact human beings are very efficient at recognizing faces, even from poor

quality images, and you have the makings of a rich forensic resource for solving crimes.

In the past it would be reasonable to assume if you were the one wielding the camera, then you

would not be in the picture.

But a new study published in the journal PLOS ONE is now turning this assumption on its

head.

Lead investigator Dr. Rob Jenkins, of the Department of Psychology at the University of York,

says:

"The pupil of the eye is like a black mirror. To enhance the image, you have to zoom in and

adjust the contrast. A face image that is recovered from a reflection in the subject's eye is about

30,000 times smaller than the subject's face."

Researchers found that participants were able to identify the tiny faces of people reflected in the eyes of photographed subjects, findings which could help solve crime one day.

For the study, he and co-researcher Christie Kerr, of the School of Psychology at the University

of Glasgow, zoomed in on high-resolution passport-style photographs and recovered images of the

faces of bystanders from reflections in the eyes of the photographed subjects.

Despite the rather low resolution of the blown up images (some of them were only 27 pixels

wide), observers were able to accurately identify who the bystanders were.

When observers were presented with the images in a face-matching task, they were able to identify the tiny faces 71% of the time for unfamiliar faces and 84% of the time for familiar faces.

In another test of spontaneous recognition, the observers were able to reliably name a familiar

face from just the low-resolution eye reflection image.

Dr. Jenkins says:

"Our findings thus highlight the remarkable robustness of human face recognition, as well as the

untapped potential of high-resolution photography."

The researchers suggest their study shows it may well be possible to use this knowledge to help

solve crimes.

For example, analyzing images reflected in the eyes of victims photographed in child sex abuse or

hostage situations, or images of people retrieved from cameras seized as evidence in

investigations, could yield vital clues about perpetrators or their associates, or link individuals

to particular locations.

Meanwhile, a study published in the Proceedings of the National Academy of Sciences

in 2010 found that hand bacteria

could also aid forensic identification.

It appears that whenever we handle objects, we leave behind unique bacterial communities that

could one day sit alongside DNA and fingerprints as part of the forensic toolkit for identifying

individuals.

Written by Catharine Paddock PhD

Copyright: Medical News Today

Not to be reproduced without the permission of Medical News Today.

Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.