Iris scans analyze the features that exist in the colored tissue surrounding the pupil which has more than 200 points that can be used for comparison, including rings, furrows and freckles. The scans use a regular video camera style and can be done from further away than a retinal scan. It will work through glasses fine and in fact has the ability to create an accurate enough measurement that it can be used for identification purposes, and not just verification.
How it Works:
The user places himself so that he can see his own eye's reflection in the device. The user may be able to do this from up to 2 feet away or may need to be as close as a couple of inches depending on the device. Verification time is generally less than 5 seconds, though the user will only need to look into the device for a couple moments.
To prevent a fake eye from being used to fool the system, these devices may vary the light shone into the eye and watch for pupil dilation.
The idea of using iris patterns for personal identification was originally proposed in 1936 by ophthalmologist Frank Burch. By the 1980's the idea had appeared in James Bond films, but it still remained science fiction and conjecture. In 1987 two other ophthalmologists, Aran Safir and Leonard Flom, patented this idea, and in 1989 they asked John Daugman (then teaching at Harvard University) to try to create actual algorithms for iris recognition. These algorithms, which Daugman patented in 1994 and are owned by Iridian Technologies, are the basis for all current iris recognition systems and products.
Law enforcement agencies in the United States began using it in 1994 when the Lancaster County Prison in Pennsylvania became the first correctional facility to employ the technology for prisoner identification. In Berkshire County, the technology is used in the newly built Berkshire County Jail as a security check for employees. The Charlotte/Douglas International Airport in North Carolina and the Flughafen Frankfort Airport in Germany allow frequent passengers to register their iris scans in an effort to streamline boarding procedures. There is discussion that banks may someday make iris scans a routine part of ATM transactions, and some have begun taking the first steps in testing out these systems.
The use of iris scans as part of the booking procedure along with fingerprints is just beginning to come into existence. Police stations around the country have been looking into the technology and some, including the Barnstable County jail in Massachusetts which put in a system in early 2002. The power of this biometric may make it rival fingerprints for booking situations where identification and verification are vital.
The uniqueness of eyes, even between the left and right eye of the same person, makes iris scanning very powerful for identification purposes. The likelihood of a false positive is extremely low and its relative speed and ease of use make it a great potential biometric. The only drawbacks are the potential difficulty in getting someone to hold their head in the right spot for the scan if they are not doing the scan willingly. It also takes up a bit more memory for the data to be stored, but with the advances in technology, this is unlikely to cause any major difficulty.