Blood Test

Vascular patterns provide new means of identification and authentication

4 min read

Researchers have been toiling for years to produce biometric devices to quickly and reliably indicate whether people are actually who they say they are, using traits unique to them. These traits include fingerprint patterns, the arrangement of tissue in the eye’s iris, and the timbre of a person’s voice.

A new type of biometric identification device takes advantage of the fact that the network of vessels in each person’s hand forms a pattern that can be distinguished from anyone else’s. The leading manufacturers of these vascular pattern recognition devices, TechSphere, of Seoul, South Korea, and Japan’s Fujitsu and Hitachi, have already sold tens of thousands of them in Asia and Europe.

Businesses, schools, and apartment buildings are using vascular recognition for physical access control. Companies are also beginning to adopt the technology to manage access to their information technology infrastructures. Vein pattern recognition has been used to screen passengers at South Korea’s Inchon International Airport and to control access to the tarmac at several Canadian airports.

Vascular recognition already has won wide acceptance in banking, a high-­profile use that seems ­destined to grow. So far, more than a dozen Japanese banks and credit unions have made hundreds of ATMs featuring ­vascular sensors available for everyday use. They have chosen these recognition systems in order to meet the standards for data protection in the country’s Personal Information Protection Act, which was adopted in April 2005. Dozens of other financial institutions have also announced plans to introduce vein-reading ATMs over the next several years.

In the vascular recognition systems developed by Fujitsu and TechSphere, after inserting a banking card in a cash machine, the user is prompted to hold a hand near an infrared light source. (TechSphere’s system illuminates at the back of the hand, while Fujitsu’s scans the palm.) The light source is paired with a charge-coupled device similar to the one used in standard digital photography. As the near-infrared light passes through the body tissue, it is reflected by the hemo­globin in the blood. This reflected light picked up by the CCD reveals an image of the blood vessels [see photo, "Life Lines"].

Hitachi’s system works on the same premise, but instead of focusing on the blood vessels in the hand, it uses those in the index or middle finger.

Among the reasons that vascular pattern sensing was chosen over fingerprint scanners was that users don’t have to touch the sensors in order to conduct transactions—a concern in some Asian countries where hygiene is an exceptionally important cultural value.

Within a second or two, the system filters the digitized image, creates a template that it can compare with the encrypted image template associated with the authorized user, and decides whether they match. The template data can be stored either directly on the chip in a smart card or in a central database. Many of the early adopters of the technology have opted for the smart card, because it allows customers to maintain possession of their digitized records and frees the service provider from having to maintain databases.

Makers of vascular recognition systems say their advantages over fingerprint scanners will soon make them market leaders. Fooling these systems is exceedingly difficult, says Terry Wheeler, president of Identica Corp., in Tampa, Fla., the exclusive reseller of TechSphere’s VP-II system in North and South America. ”Unlike fingerprints, [vein patterns] are not visible to the naked eye and copies aren’t left on just about every surface a person touches,” he says.

And because the data on a digital template is encrypted, a thief can’t use it to re-create the digital image of the real ­credential holder’s vascular pattern. ”If they were able to go onto my card and ­figure out how to get through the encryption, all they would get is a numerical ­version of my template, which is absolutely useless,” says Wheeler.

He notes that vascular sensors boast usability and durability. ”Because we’re going below the surface of the skin, we don’t have issues associated with fingerprints such as finger contamination by dirt or moisture.”

The vascular pattern recognition systems currently on the market also benefit from advances in the algorithms used to make the permanent, authorized user templates and to match them with the templates made for subsequent user authorizations. Hitachi, for example, has developed an algorithm that pinpoints the position of the center of each blood vessel. This means that fluctuations in the width and brightness of the blood vessels due to variations in outside temperature and the person’s blood pressure do not affect the matching procedure.

The result is a reduction in the devices’ false acceptance and false rejection rates that, as Identica’s Wheeler points out, makes ”the chances of a thief’s being inadvertently confused with the real account holder literally one in a million.” That and similar manufacturers’ claims got a big boost on 14 September, when New York City�based International Biometric Group (IBG) released the results of the first independent tests of Hitachi’s and Fujitsu’s vascular ­pattern systems.

The devices ”demonstrated a strong combination of usability and accuracy,” said Michael Thieme, director of special projects at IBG. Each system recognized all but one of 1290 test subjects and, when comparing a test subject’s vein pattern with the known pattern of an authorized user, had error rates lower than nearly all of the 60 biometric systems the company had tested previously.

But the technology has its critics. Walter Hamilton, chairman of the International Biometric Industry Association, a lobbying group in Washington, D.C., that represents mainly fingerprint sensor makers, points out that questions still remain about whether the vascular pattern in someone’s finger or hand stays the same as the person ages. Even if veins don’t change over time, he says, the devices based on them still have to compete with cheaper, more established biometric methods for which there is more product choice. He says the vein sensors will find their niche in the physical access control market, where, say, ”a unit mounted outside, exposed to the elements, would perform well compared with fingerprint recognition or with face recognition, which would be interrupted by variations in lighting.”

But TechSphere, Fujitsu, and Hitachi are optimistic that the potential applications for their products are just as varied as those for fingerprints. Fujitsu’s PalmSecure authentication device, released in June, measures just 35 by 35 by 27 milli­meters—small enough to plug into a laptop’s USB port. According to Junichi Hashimoto, a researcher at Hitachi’s Information & Telecommunication Systems Group, the company is already developing finger-vein readers for cellphones.

Hitachi is exploring other areas as well. In October 2005, it introduced a system that makes it possible to unlock doors or vaults simply by gripping a handle with a vascular pattern sensor mounted on it.

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