91色情片

FORGET passports and driving licences. Soon the only proof of identity you鈥檒l
need is your eyes. A study published this week comfirms that iris scans are
faster and more accurate than any other computerised means of identifying
people, such as fingerprint, face or voice recognition.

Most iris recognition systems are based on software created by John Daugman
of Cambridge University. An image of an iris, with all the tiny pits, ridges and
strings of tissue that make it unique, is turned into a series of
three-dimensional contour maps. Then this information is compressed into a code
of 1s and 0s just 2048 digits long. This code can be stored or checked against
existing records in a database for a match.

Daugman has used this system to make 2.3 million random comparisons between
images of over 2000 different irises from people in Britain, the US and Japan.
The study shows that if two codes match by 75 per cent or more, there鈥檚 only a 1
in 1000 billion chance that the match is wrong. With just 12 billion human eyes
on the planet, that鈥檚 quite secure.

In another recent trial by the British government, there were no false
matches in over 2 million tests, whereas the failure rate for other methods such
as voice recognition ranged from 10 to 25 per cent. And an Eye Ticket
Corporation project at an airport in North Carolina has correctly identified
half a million volunteers with no mismatches since May last year.

Such results prompted the International Air Transport Association to
encourage London鈥檚 Heathrow airport to try using iris scans for ticket and
immigration control, in the hope of speeding up check-ins. The scans can be done
with a video camera in a few seconds. A pilot project, run by Eye Ticket, will
begin in October with a group of frequent travellers who are a low security
risk.

鈥淥ur aim isn鈥檛 to replace immigration staff, it鈥檚 to add to it,鈥� says Anna
Dorricott, a spokeswoman for Britain鈥檚 immigration department. It is interested
in the method, but is waiting for the results of the trial. 鈥淲e鈥檙e standing back
and just watching.鈥�

But John Tincey of the Immigration Service Union says that while the scan
checks people鈥檚 identities, it doesn鈥檛 assess their intentions. He says it
should only ever be used for a select group of people, such as frequent business
flyers.

Daugman admits that the evidence for irises staying the same with age isn鈥檛
extensive. 鈥淏ut I have seen ophthalmologists鈥� photographs of irises taken 25
years apart, and I could see no changes of any details.鈥�

As for hacking out someone鈥檚 eyeball and holding it up to the camera, Daugman
says this wouldn鈥檛 work. 鈥淭he pupil dilates to as much as 80 per cent, and the
cornea turns cloudy,鈥� he says, and both effects are easily detectable. 鈥淏elieve
it or not, this was actually the first question that the FBI and NSA gumshoes
asked me.鈥�

Curved contact lenses used to mimic an iris can also be distinguished from a
real iris, which is nearly flat, he says.