New tech in digital photography could help spot criminals

New research led by a psychologist at the University of York is using advances in the level of detail available in digital photography to harness this human ability for use in forensics.

The researchers said that in crimes in which the victims are photographed, like hostage taking or child sex abuse, reflections in the eyes of the photographic subject could help to identify perpetrators.

Images of people retrieved from cameras seized as evidence during criminal investigations may be used to piece together networks of associates or to link individuals to particular locations.

As the most commonly photographed objects are faces, there is potential in mining detailed facial images for hidden information.

Until now, photographers might reasonably have assumed that their own face was absent from the image. But the research, led by Dr Rob Jenkins overturns this assumption.

By zooming in on high-resolution passport-style photographs, Dr Jenkins and co-researcher, Christie Kerr, of the School of Psychology, University of Glasgow were able to recover the faces of bystanders from reflections in the eyes of photographic subjects.

To establish whether these bystanders could be identified from the reflection images, the researchers presented them as stimuli in a face-matching task.

Observers who were unfamiliar with the bystanders' faces performed at 71 per cent accuracy while participants who were familiar with the faces performed at 84 per cent accuracy.

The study has been published in PLOS ONE.