Nobody really saw a compelling need for the sometimes-costly security devices that use physical characteristics such as fingerprints, facial or hand geometry, or iris or retinal scans to authenticate identity.
Even more damaging to the industry's growth was the public's reticence about providing such unique and personal identifiers.
The events of September 11 changed all that.
"Biometrics' time has come," said Joseph Atick, chief executive and chairman of Visionics, a company headquartered in Jersey City, New Jersey, that specialises in facial-recognition systems, and one of several industry leaders now talking to major US airports. The company already has a successful system in operation in a borough of London and at the main airport in Iceland.
Yet some experts fear the government, private industry and especially the public, in a desperate attempt to feel safe once again, could be placing too much trust in the still nascent technologies, which work very well under specific conditions, but are almost surely not going to provide "the instant magic bullet" that society is so anxiously seeking.
"We need to find the smartest way to implement biometrics in this environment, rather than just a knee-jerk reaction where we throw some technology out there and see what sticks, " said Michael Thieme, a senior consultant at the International Biometrics Group, a New York-based consulting group. "There are cases where better human guards might be a better use of our money."
Many biometric experts think that much of the earlier hoopla about privacy concerns was unfair, a result of the public's lack of understanding. Biometric databases contain complex mathematical models of minute details about specific physical characteristics, but these algorithms cannot be reverse-engineered to produce an actual image. Rather, software compares these encrypted points in the database with the live person being scanned.
In any event, fair or not, most such Orwellian objections have been quickly set aside.
"We cannot look at these things through the same glass; we have a whole different perspective now," admitted Gwen Chandler-Thompson, a Duval County councillor who opposed such privacy intrusions just a few months earlier.
An October survey by Harris Interactive showed that 82 per cent of the respondents said they would be willing to have their fingerprints scanned for increased airport security. In a separate survey, 86 per cent of those interviewed advocated the use of facial-recognition technology to scan for terrorists.
Companies, both public and private, that develop any type of biometric product have been virtually overwhelmed with the surge of interest in these once mistrusted technologies. Yet even the officials of these firms urge caution.
"It is very important to separate the hype from the reality," said Gene Chayevsky, chief executive of BioLink Technologies in Miramar, Florida. One of the areas the privately held company specialises in is building dedicated computer servers that can store millions of authentication records and match them quickly.
"Biometrics is not a cure-all for everything, it is just an authentication system, which is a component of a bigger security system. If the other components are weak, biometrics alone isn't going to help the world solve the terrorist problem overnight," Chayevsky said. "But it can go a long way in improving overall security if used in the right way."
While every type of biometrics has become a hot topic, facial-recognition systems have garnered the most attention.
There are no fingerprints, iris scans or hand geometry measurements available for international terrorists, but there are some intelligence, passport and driver's licence photos in scattered files. With international cooperation, these photos could be used to build a model based on as many as 80 measurement points on the face, ranging from the distance between features to the proportional size of one feature in relation to another.
Yet critics argue that facial recognition systems are only as good as the databases they are based on. Poor photos can challenge a system, and many argue the technology can be easily defeated by disguises, plastic surgery - even changes in weight and facial hair, leading to an unacceptably high rate of false alarms.
One US Defence Department-sponsored facial-recognition test frequently quoted in the industry, according to the Biometric Digest, a St Louis-based industry newsletter, stated that in order to detect 90 per cent of the "bad guys" in a database, it would be necessary to stop one out of every three people.
Visionics' Atick brushes aside such criticisms. A good facial recognition system takes measurements of areas that cannot be altered enough by disguises to defeat the system, he insisted. He noted there are important measurements - such as under the nose to the lip or from temple to temple - that are difficult to alter and that many measurements go into each composite.
Atick disputed high failure rates and noted his company's surveillance cameras in the London borough of Newham turn up about three false alarms a day out of as many as 100,000 scans, and can spot 90 per cent of the "bad guys" in its database.
"The better the photo, the higher degree of confidence, but airport systems are designed to work as a screening tool alongside human guards who do their own form of profiling," he said, adding that guards can watch out for people trying to avoid or cover up for the camera and can set systems not to sound an alert when there is a low level of confidence in the match. He suggested setting up scanning cameras at every metal detector, rather than in crowded hallways.
"Instead of just X-raying luggage, scan a face as it walks through and check it against the Watch List," he said.
In administering biometric systems, some suggest that "managed databases" of proven good guys, not bad guys, might be a more feasible approach. Frequent travellers who want to avoid cumbersome security checks could register once by submitting to background checks and biometric scans and receive a smart card that contains their encoded data.
A variation of the "good guy" database that could be set up for more widespread airport use would "enrol" passengers' biometric data at the ticket counter and record it on a smart card, then scan it at the gate, to make sure the same person who bought the ticket is the one getting on the plane.
A Belfast, Northern Ireland, subsidiary of Boca Raton, Florida-based Sensormatic Inc makes a system that allows the check-in airline agent to put a bar code on the reverse of a boarding pass that can be scanned at the gate to produce a photo of the passenger taken at check in.
"Last week when I flew I had to show my driver's licence seven times before I could get on an airplane, and that doesn't even guarantee who you are," said Dore Perler, chief executive of Sense Technologies in Tamarac, Florida, which develops smart cards that incorporate both finger and facial data. "We make sure you are who you say you are, and you can get set up in the system in less than a minute."
