Reflections in eyes could be used to help solve crimes
Researchers are developing technology that can zoom in on the eyes of a subject in a photo and get an image of what they are seeing
"I get lost in your eyes," you say? Researchers are working on ways to find you and save the resulting image for posterity - or for a criminal investigation.
Scientists have found that photo portraits of an individual can yield images of the photographer or people standing close to the photographer. These additional images appear as reflections in the eyes of the photo's subject.
Even though enhancements of the images appear blurry, they carry enough detail to allow others to identify the people reflected in the subject's eyes.
Several research teams are pursuing the approach, known as corneal imaging, with a range of applications in mind. Criminal forensics and surveillance, including the potential to reconstruct the immediate environment that the subject of the photo occupies, are some examples. Others include advanced computer graphics, facial and iris identification, and robotics, researchers say.
Much of this work involves close-ups of the eye, plus sophisticated computer processing, to yield sharp reflected images.
But Dr Rob Jenkins, with the University of York in Britain, and collaborator Christie Kerr at the University of Glasgow, have shown that useful images for identifying persons of interest in a crime do not have to be razor sharp, given humans' remarkable ability at pattern recognition.
Faces can be reconstructed from images taken with commercial digital cameras and enhanced with off-the-shelf image-processing software.
"You could think of it as a foray into extreme facial recognition," Jenkins said.
"Yes, the camera can resolve the face, and yes, the brain can identify it," he wrote in an e-mail, "but both systems are pushed to their limits, and neither could perform the feat alone."
For the experiment, the duo used a high-end digital camera and sat each of five volunteers for a passport-photo-like shot, using studio lighting. When a volunteer was not being photographed, he or she stood close to the photographer to be included in the reflection off the subject's corneas.
Armed with the images taken from the reflections, as well as the original digital images, Jenkins then asked two groups of people to try to match the images. Also included were studio portraits of people not among the five photographed.
One group unfamiliar with the five photo subjects was asked whether pairs of reflected and original images matched. This group amassed a 71 per cent success rate for either correctly identifying a match or ruling out a match. Another group familiar with the photo subjects averaged an 84 per cent success rate.
Then, Jenkins joined the five subjects in a line-up to see how well a new group of volunteers unfamiliar with the experiment but familiar with Jenkins could spontaneously identify him from among the others.
The volunteers also were asked to rate the confidence with which they could pick him out from among the group. Think police line-up here.
Nine out of the 10 volunteers identified the blurry corneal image of Jenkins with a confidence level of nearly 80 per cent.
The researchers hold that the corneal images not only were matchable to existing, better-quality images of the same person, but also allowed someone to identify a particular individual whom they knew. This was a surprise given the poor quality of the reflection-based images.
Although the study represents an initial exploration of the potential value of extracting facial information reflected in the eyes of others, the approach's usefulness as a forensics tool is far from assured, notes Professor Lawrence Kobilinsky, who heads the department of sciences at John Jay College of Criminal Justice in New York.
The results show "some potential for criminal investigations", he says. "But at this stage, there are too many variables that cannot be controlled in an authentic case or criminal matter."
Ultimately, the key to identification may rest less with the camera resolution than with the people making the identification, he writes in an e-mail.
The experiment's results appear in the current issue of the journal PLOS One (Public Library of Science).