A quick, simple, noncontact, noninvasive way to prove who you are can race you through customs, let you into restricted areas, or keep your children safe at school. It’s all in the eyes.
Stephanie vL Henkel
Now let’s see what iris recognition is, beginning with a few facts about the eye. The white part is the sclera, the dark disc in the center is the pupil, and the colored circle between the sclera and the pupil is the iris. The iris begins to form in the third month of gestation and is for the most part complete by the eighth month. Even though pigmentation can continue to change for months after birth, color is not important in iris recognition. What are significant are features such as furrows, ridges, rings, freckles, and other elements of the patterns that make every iris unique—even your two eyes are not identical to each other. Short of trauma severe enough to cause blindness, your iris patterns will never change.
Conversely, fingerprints can be altered or even obliterated, and small children’s prints are extremely evanescent due to the volatility of the natural oils in juvenile skin. Identical twins can defy even their parents’ efforts to tell them apart by their faces, gestures, voices, and gaits. A stolen wallet contains everything the thief needs to pass as you. And we all know how easy it is to forget our PINs.
So let’s take a closer look at IriScan, an iris recognition, image storage, and template-matching system developed and marketed by Iridian Technologies. Then we’ll check out some examples of where it’s at work today.
To be scanned, you look from a distance of 5–24 in. into a monochrome CCD camera operating on NIR in the 700–900 nm band, invisible and safe to the human eye. To capture all the pattern details, the camera needs to resolve at least 70 pixels of iris radius. Even so, your iris is photographed in a few seconds. The image is first processed by software that localizes the inner and outer boundaries of the iris, as well as the eyelid contours, in order to extract only the iris portion. Mathematical software encodes the iris pattern by means of quadrature 2D Gabor wavelets in a process called demodulation. The result is a very compact yet complete description of the iris pattern, regardless of size and pupil dilation, in only 512 bytes. The phase sequence, called an IrisCode template, is immediately encrypted to eliminate the possibility of identify theft and to maximize security.
The IriScan at Work
Air Travel. CANPASS, a joint initiative of the Canada Customs and Revenue Agency and Citizenship and Immigration Canada, serves travelers at Vancouver (BC) International Airport. Passengers who have established their credentials of trustworthiness and stored their IrisCodes are allowed to clear customs quickly and without hassles. Open at present to citizens and permanent residents of the U.S. and Canada, the program will in time be extended to other visa-exempt countries and NAFTA business travelers.
Schools. We’ve all read too many news stories about young children picked up at school in what amounts to an abduction by one parent estranged from the other. That’s unlikely to happen at the New Egypt school in Plumsted, NJ. Nor will the facility be entered by anyone who has no business there. Enrollment in the scan plan is required of school employees, and parents and other caregivers are invited to join. Nonparticipating parents must show an ID and wait for their particulars to be keyed into a computer before a child is released into their custody.
Prisons. All staff members at the Lancaster County (PA) Prison must submit to a background check (we should hope so!) and store their IrisCodes. More than 1000 regular visitors have signed up too, which serves to speed up their admittance on visiting days. In a separate application, prison inmates are scanned at both booking and release to thwart identity fraud. According to prison officials, it’s working well.
At the University of South Alabama Hospitals in Mobile, iris recognition-enabled medical records management makes sure that only clinicians with approved access privileges can view medical information and associated reports. The system is part of the university’s strategy for compliance with the Health Insurance Portability and Accountability Act (which we all know as HIPAA).
John Daugman, Ph.D., OBE, has researched and written extensively on iris recognition technology. Among the excellent papers available at his Web site is “How Iris Recognition Works.”
Stephanie vL Henkel is Executive Editor of Sensors.