The divergent airport-security approaches of two facial-recognition firms, Advanced Digital Imaging Research (ADIR) of League City, Texas, and Sunnyvale, Calif.-based Applications for Vision (A4Vision), likely will be a source of debate in the biometrics industry for some time to come.
At issue is whether it's better to push on with the "positive authentication" approach, where a facial image is matched to other identifying information such as an employee number, or pursue a less-well-developed approach often known as "one-to-many," where a facial image is compared to an image database for an attempted match.
The latter also is the technique that ADIR is trying to perfect in a two- week-old experiment at Waco Regional Airport (ACT) in Texas. ADIR has already assembled a "known database" of faces from its own employee files and that of its parent company, Chatsworth, Calif.-based Iris International, Inc. [IRIS]. ADIR also wants to assemble an anonymous sampling of 10,000 new faces from air travelers passing through the Waco airport. Then, by summer's end, the firm hopes to discover several new ways of refining its technology, ADIR President Ken Castleman says.
But A4Vision's CEO, Grant Evans, thinks ADIR has its work cut out for it. Trying to reduce the error rate of a one-to-many technique so that it approaches a useable level has already proven to be "very difficult," Evans tells Air Safety Week. "I applaud the company on pushing the envelope," but doubts that its efforts will be successful. Where the technique already has been tried, it has "failed dramatically." And if the latest experiment fails, the attendant publicity may hurt the rest of the industry.
When another form of biometric identifiers -- fingerprints -- are compared against a known database (like those with criminal histories), there's always a few "false positives" where sets of prints appear to match a file in the database, Evans explains. As the number of new prints being checked increases, the number of false positives also grows.
Evans says that a governmental study conducted at a large airport, and scheduled for public release within a month or so, will show that A4Vision's brand of 3D facial biometrics in positive authentication is highly accurate. Compared to error rates averaging 30 percent for several other firms' biometrics, including facial imaging, iris scanning and fingerprinting, A4Vison's error was well under 1 percent.
For his part, ADIR's Castleman also admits that prior testing of the one- to-many technique has not been successful. Waco, however, will be the first time such a large sample of new faces will be used, and the current months-long trial is only for improving the prototype, he tells Air Safety Week. In the next testing phase, possibly beginning late this year or early in 2006, ADIR hopes to check its system at airport checkpoints. In informal discussions, TSA has been supportive of ADIR's efforts so far, and Castleman believes it likely that the agency will support a "real world" trial on arriving passengers.
From signs posted throughout Waco airport explaining the project's scope and purpose, passengers can agree to be voluntary project participants. They will leave their facial images at an ADIR portal, which resembles a magnatometer, and features multiple cameras to get a composite image of subjects' faces. Although there will be a number attached to their images, ADIR will keep no other identifying information, nor will the images be passed on to any law enforcement agency. Waco Regional was chosen as the test site not only because of its proximity to ADIR's offices -- no more than 250 miles -- but also because it is about the right size for this type of testing.
The firm will test hundreds of measures of facial features, alone and in combination, in an attempt to reduce the frequency that any of the new 10,000 faces are mistakenly identified as one of the faces in ADIR's known sample of company employees and family members. Facial measures will range from the shape of the bridge of the nose to eye-socket curvature -- "everything we can think of to measure," Castleman adds.
With the current state of the technology, it's also important that air travellers being scanned show some degree of cooperation, both Castleman and Evans say. That is, each passenger must briefly pause to have an image recorded and analyzed. As passengers pass through ADIR's portal device, which resembles a magnetometer, they also will be asked to look more or less straight ahead and assume a neutral facial expression.
Hopefully, these instructions won't have the opposite effect on some air travellers. It wouldn't do the industry much good, either, if passengers with giggling fits are detained or arrested.
So ADIR also wants to see just how sensitive its system will be to certain facial expressions. A broad grin, or laughter could be more problematic than a mild scowl, especially if mouth width is one of the determining measurements. On the other hand, distance between pupils is not likely to be affected by any temporary expression.
At any rate, passengers who attempt to game the system by contorting their faces would not get very far. Such behavior would be a red flag for the security personnel to question the individuals or start secondary screenings, both Castleman and Evans say.
The current technology also won't work on people who are simply walking through an area, or simply pass by somewhere near a camera (within 10-15 feet), Evans says. I4Vision has had requests to develop such a system, but for now, Evans believes it's too difficult to capture accurate images in quick succession from so many moving targets.
Evans explains that his firm's 3D imaging solves some of the problems posed by slightly older 2D facial recognition technology. In 2D, if a person moved, the image was blurred. But with A4Vision's 3D imaging using only one camera, a composite is assembled from 14 images taken in .84 second. Also, when using 2D equipment, images couldn't be read right if a person's face veered from the ideal axis -- as in turning slightly to the side. But the new technology can tolerate facial turns of up to 30 degrees to the left or right.
On older devices, the low lighting common in the middle of airport checkpoints also produced unclear images. A4Vision solves that problem with infrared lighting.
>>Contacts: Ryan Zlockie, I4Vision, 408-329-4578, firstname.lastname@example.org; Ken Casteman, ADIR, (281) 535-1889, ext. 427, email@example.com
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