The face of security

Biometric systems, which use personal characteristics such as fingerprints

or facial features to identify individuals, also are expected to play a

greater role in homeland security.

Joseph Atick, chairman and chief executive officer of Visionics Corp.,

a developer of biometric systems, said the government could build a "network-based

shield" to try to prevent terrorists from gaining access to airplanes or

entering the country at border crossings, for example.

The system would consist of cameras located at key areas that could

capture facial images of people and then compare them with images of suspected

terrorists stored in a database.

But with several hundred million airline passengers per year in the

United States, the system will have to be able to handle thousands of image

matches per second, a scale similar to that of the credit card authorization

systems used today at cash registers in stores.

Because each facial scan produces a file that is compressed to only

84 bytes of data, Atick said, current hardware would be capable of handling

the anticipated volume and still provide the desired 2 second to 3 second

response time for queries.

Improvements still need to be made in the image enhancement and modeling

software, which plays an important role in the system. "The images coming

in from the databases of suspected terrorists are often taken under very

uncontrolled conditions," Atick said. Problems include poor lighting, subjects

not facing the camera directly or subjects with unusual facial expressions.

Certain modeling and enhancement software is already in use to clean

up lower quality images. The challenge now is to use those techniques to

correct live images in real time to increase the accuracy of the matching

process.