Scientists have developed a new technique which can recover the faces
of bystanders from reflections in the eyes of photographic subjects, a
development that could help identify criminals.
As the most
commonly photographed objects are faces, there is potential in mining
detailed facial images for hidden information, researchers said.
now, photographers might reasonably have assumed that their own face
was absent from the image. But research, led by Dr Rob Jenkins from
University of York overturns this assumption.
By zooming in on
high-resolution passport-style photographs, Jenkins and co-researcher,
Christie Kerr from the University of Glasgow were able to recover the
faces of bystanders from reflections in the eyes of photographic
The recovered bystander images could be identified accurately by observers, despite their low resolution.
establish whether these bystanders could be identified from the
reflection images, the researchers presented them as stimuli in a
Observers who were unfamiliar with the
bystanders' faces performed at 71 percent accuracy while participants
who were familiar with the faces performed at 84 percent accuracy.
In a test of spontaneous recognition, observers could reliably name a familiar face from an eye reflection image.
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. Our findings thus highlight the remarkable
robustness of human face recognition, as well as the untapped potential
of high-resolution photography," Jenkins said.
The researchers say
that in crimes in which the victims are photographed, such as 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.
The study was published in the journal PLOS ONE.