A standard for collection of biometric data has been in demand pretty much since 2001. In that time, the National Institute of Standards and Technology has been trying to overcome the significant technological hurdles in creating a specification, especially when dealing with iris recognition. The agency has had to account for this delay several times in congressional hearings, the latest of which was last month, chaired by Rep. John Mica, R-Fla.
Now, NIST has issued a paper outlining its new specifications for its Personal Identity Verification system. It details methods of collection of fingerprint, iris and even facial-image recognition data. It also standardizes the format for that information, and how it will be stored on an employee’s PIV card. This will allow users to simply have their fingerprint read while a machine compares it to the image files stored on the card, as opposed to the employee needing to remember and accurately enter a PIN.
For many users, fingerprint identification can prove problematic for various reasons. The fingerprints sometimes are too dry to yield an accurate result, and other factors such as skin lotions, injury or illness can further complicate things. That’s why many agencies may choose to add iris images as an alternative, as their collection is affected by fewer external factors.
The trick to making this work is in compressing the image files so that they fit on the card, but still have enough information to be unique and useable. After applying standard compression algorithms to a large number of iris images and then using these compact images with state-of-the-art recognition algorithms, NIST researchers determined an iris image compressed to 3KB provides enough detail to accurately recognize an individual’s iris.
“More importantly,” says Biometric Testing Project Leader Patrick Grother, “the iris standard ensures that the iris data is interoperable, that is, it can be exchanged easily between cameras and readers from different makers and across the world.”
This specification states PIV data needs to remain valid for 12 years after collection. A study published by Notre Dame faculty seemed to indicate a person’s iris tends to change much quicker as that person ages.