Matching a face to a photo is trickier than once thought, a new study says - even for facial recognition computers designed to do just that.
By Megan Lane
BBC News Magazine
Jeffery Archer turns side-on. Alain de Botton and Terry Gilliam tilt their heads to the side, while singer Kate Nash chooses an over-exposed shot as it bleaches out her freckles. And David Cameron? He grins.
These are just a few of the tricks we once used to make our passport photos look less like mugshots on "WANTED" posters.
But such tactics are off-limits under stringent rules introduced two years ago, under which none of these photographs, to be auctioned for the charity Barnados, would be accepted.
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The new rules reflect the importance placed on facial recognition in the expansion in security and surveillance efforts in the past few years.
But this could be misplaced as both humans and computers struggle to match people's faces to their photos, says Rob Jenkins, a psychologist studying the problem at Glasgow University. When volunteers were presented with six different images of him and six of another man, most failed to spot which face was which.
Rob Falconer with his e-passport pic (right) and composite photo
"This routine task, performed hundreds of times every day by passport officers, security guards and police officers turns out to be highly error-prone," Dr Jenkins told the BA Festival of Science in York this week.
His solution is to combine 12 images of one person to produce an "average" face which is easier to recognise. Too expensive to do nationally, he says this may help the authorities in specific cases.
Look to the front
It's a far cry from the days when you just had to remember not to blink or smile broadly (then repeat, having wound the photo booth stool up or down). Today international rules for biometric passports set out 17 strict criteria and include:
Hence the adage that airline travel is nature's way of making you look like your passport photo - glassy of eye and blank of expression.
- 65-75% of photo must be of the face
- Background must be plain white, cream or light grey
- Face forwards, looking straight towards the camera
- No grinning, frowning or raised eyebrows
- No hair or glasses frames obscuring eyes
- Nothing can cover the outline of eyes, nose or mouth
- Head covering allowed if worn for religious or medical reasons
The rules allow passport photos to be used to map the carrier's face based on characteristics such as distances between the eyes, nose, mouth and ears. These coded details are contained in the memory chips of e-passports which a year ago became standard issue.
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17.5% eyes obscured, often by hair or glasses frames
12.5% not neutral expression
7.5% not looking straight at camera
But the technology to automatically "read" photos has been slow to appear. While it has weeded out several thousand fraudulent applications in passport offices around the country, most airports still rely on an immigration official looking from passport photo to carrier.
However, this summer Faro airport in Portugal has used a facial recognition camera for e-passport holders.
"But the camera doesn't remove the need for immigration officers for when something goes wrong - and it always will, you can't do everything with technology," says an Identity and Passport Service spokesman.
Nor is it just government officials who are after your approved image. This year Glastonbury festival-goers had to provide passport photos in an effort to stymie ticket touts.
Bain of the vain
But the very constraints of this photo format can fascinate.
The French film Amelie revolves around a young woman who falls for a man who collects discarded photo booth snaps. He reassembles the images and comments on the people depicted. With few clues from the head and shoulders shots, his imagination takes flight.
Photo booths evoke time and place
Andy Warhol used a photo booth in 1963 to create a series of self-portraits (which would be rejected by the passport office today as he wears sunglasses or looks away in every frame).
And when Tony Blair posed for Rankin soon after the Iraq invasion in 2003, the photographer complained that the resulting rather dead-eyed portrait looked like a passport photo: "He's not giving me anything."
Passport photos remain the great untouchable in the age of air-brushing. Applicants can submit their own digital pictures, but retouching is not advised. It may alter the ratios between facial features and make it seem as if you have faked your own passport.
"Everyone, no matter how famous, on their passport pictures remains true to life, not enhanced or manipulated," says entrepreneur Roger Shashoua, organiser of the charity auction.
"I have seen powerful politicians shielding their passports from their loved ones, embarrassed by their photos. I have seen beautiful, surgically-enhanced women, desperate to avoid people seeing the 'before' pictures. They are a connection to travel from a bygone age, an archaic means of identification in a technical era."