Security screens show biometrics not skin deep.

Use of optical scans to identify people is well known. A less popular method uses near-infrared light to obtain an image of the blood vessel pattern in the finger. The system is said to be as accurate as a fingerprint.

Matched with images from employees, and meshed with a security code, duplication of the internal pattern is nearly impossible to duplicate, even with a severed finger, according to iaccess Systems Inc., which sells the technology.

The technique echoes identification methods that recognize blood vessel patterns in the retina, a system that ranks as one of the oldest forms of biometrics. In the 1930s, researchers suggested that the patterns of blood vessels on the back of the human eye were unique to each person. Using that technology for a finger scan, according to iaccess, brings certain advantages, including the ability to miniaturize the equipment for widespread installation and to overcome people's innate reluctance to have their eye sockets scanned at close range.

The first facility scheduled to use the system was a 156-unit con-dominium in Osaka, Japan, completed in March. Other Japanese customers include a nuclear power research facility, finance corporation headquarters and data warehouse. Company officials told National Defense they see a robust market in the United States.