fingerprints scanned from 2 m distance

[Eugen Leitl]

http://www.technologyreview.com/printer_friendly_article.aspx?id=27052

Friday, January 14, 2011

Fingerprints Go the Distance

Scanning prints at two meters could mean safer security checks.

By Sandra Swanson

Over the years, fingerprinting has evolved from an inky mess to pressing
fingers on sensor screens to even a few touch-free systems that work at a
short distance. Now a company has developed a prototype of a device that can
scan fingerprints from up to two meters away, an approach that could prove
especially useful at security checkpoints in places like Iraq and
Afghanistan.

The device, called AIRprint, is being developed by Advanced Optical Systems
(AOS). It detects fingerprints by shining polarized light onto a person's
hand and analyzing the reflection using two cameras configured to detect
different polarizations.

Joel Burcham, director for projects at the Huntsville, Alabama-based company,
says AIRprint could help make authorization more efficient in lots of
settings. Instead of punching a keypad code or pressing fingers to a scanner,
individuals could simply hold up a hand and walk toward a security door while
the device checks their identity. "We're looking at places where the standard
methods are a hassle," says Burcham. For instance, AIRprint could be linked
to a timecard system, he says, to help avoid a logjam at manufacturing plants
at the start or end of the workday.

Slightly smaller than a square tissue box, AIRprint houses two 1.3 megapixel
cameras and a source of polarized light. One camera receives horizontally
polarized light, while the other receives vertically polarized light. When
light hits a finger, the ridges of the fingerprint reflect one polarization
of light, while the valleys reflect another. "That's where the real kicker
is, because if you look at an image without any polarization, you can kind of
see fingerprints, but not really well," says Burcham. By separating the
vertical and the horizontal polarization, the device can overlap those images
to produce an accurate fingerprint, which is fed to a computer for
verification.

The prototype device, which scans a print in 0.1 seconds and processes it in
about four seconds, can handle only one finger at a time. Also, the scanned
finger must remain at a fixed distance from the device. But by April, Burcham
expects to have made significant improvements. By then, he says, the device
should be able to scan five fingers at once even if a person is moving toward
or away from the cameras, and the processing time ought to have dropped to
less than a second.

Burcham says several potential customers have indicated that a single-finger
scanner would be sufficient for their needsbso AOS plans to sell both a
single-finger device and a more expensive five-finger device. "We're looking
at having product ready for market at the beginning of the third quarter this
year," says Burcham.

The military has a growing interest in biometric sensors that operate at a
distance. The U.S. Department of Defense awarded $1.5 million to Carnegie
Mellon's CyLab Biometrics Lab to support development of technology that
performs iris detection at 13 meters.

One potential customer for the AIRprint is the Marine Corps. Jeremy Powell,
head of identity operations at Marine Corp Headquarters, saw a demonstration
of it about a year ago. Currently, individuals entering a military
installation must place their fingers on a scanner, with a Marine standing
beside them to help ensure a viable print. Powell would prefer there to be a
safe distance between the Marine and the person being scanned. The AIRprint
device could be on a tripod and connected to a cable that runs behind a blast
wall, where the Marine could safely assess the fingerprint result, he says.

AIRprint's two-meter standoff distance represents more than a technical
advancement. "It is a step closer to being able to verify an individual's
identity from a safe distance with or without their knowledge. As with all
new technology, the hope is further advancements will follow and increase the
standoff distance," says Powell. "This could potentially allow Marines to
positively identify a target before engaging or conduct 'standoff' screenings
from the safety of an armored vehicle."

Over the past nine years, the Marines have made increasing use of biometrics
to distinguish friend from foe in Iraq and Afghanistan. Says Powell, "It's
actually been very successful so far, and technologies like AIRprint have the
potential to make it even more so."

Copyright Technology Review 2011.