NIST study advances use of iris images as a long-term form of identification
For decades, researchers seeking biometric identifiers other than fingerprints believed that irises were a strong biometric because their one-of-a-kind texture meets the stability and uniqueness requirements for biometrics. However, recent research has questioned that belief. A study of 217 subjects over a three-year period found that the recognition of the subjects' irises became increasingly difficult, consistent with an aging effect.**
To learn more, NIST biometric researchers used several methods to evaluate iris stability.
Researchers first examined anonymous data from millions of transactions from NEXUS, a joint Canadian and American program used by frequent travelers to move quickly across the Canadian border. As part of NEXUS, members' irises are enrolled into the system with an iris camera and their irises are scanned and matched to system files when they travel across the border. NIST researchers also examined a larger, but less well-controlled set of anonymous statistics collected over a six-year period.
In both large-population studies, NIST researchers found no evidence of a widespread aging effect, said Biometric Testing Project Leader Patrick Grother. A NIST computer model estimates that iris recognition of average people will typically be useable for decades after the initial enrollment.
“In our iris aging study we used a mixed effects regression model, for its ability to capture population-wide aging and individual-specific aging, and to estimate the aging rate over decades,” said Grother. “We hope these methods will be applicable to other biometric aging studies such as face aging because of their ability to represent variation across individuals who appear in a biometric system irregularly.”
NIST researchers then reanalyzed the images from the earlier studies of 217 subjects that evaluated the population-wide aspect. Those studies reported an increase in false rejection rates over time—that is, the original, enrolled images taken in the first year of the study did not match those taken later. While the rejection numbers were high, the results did not necessarily demonstrate that the iris texture itself was changing. In fact, a study by another research team identified pupil dilation as the primary cause behind the false rejection rates.*** This prompted the NIST team to consider the issue.
NIST researchers showed that dilation in the original pool of subjects increased in the second year of the test and decreased the next, but was not able to determine why. When they accounted for the dilation effect, researchers did not observe a change in the texture or aging effect. Some iris cameras normalize dilation by using shielding or by varying the illumination.
NIST established the Iris Exchange (IREX) program in 2008 to give quantitative support to iris recognition standardization, development and deployment. Sponsors for this research include the Criminal Justice Information Systems Division of the Federal Bureau of Investigation, the Office of Biometric Identity Management in the Department of Homeland Security (DHS) and the DHS Science and Technology Directorate.
*The NIST results are reported in IREX VI – Temporal Stability of Iris Recognition Accuracy, NIST Interagency Report 7948, at http://www.nist.gov/manuscript-publication-search.cfm?pub_id=913900.
**S. Fenker and K.W. Bowyer. Experimental evidence of a template aging effect in iris biometrics. IEEE Computer Society Workshop on Applications of Computer Vision, November 2012.
***M. Fairhurst and M. Erbilek. Analysis of physical ageing effects in iris biometrics. IET Computer Vision, 5(6):358–366, 2011. www.ietdl.org.
Media Contact
More Information:
http://www.nist.govAll latest news from the category: Studies and Analyses
innovations-report maintains a wealth of in-depth studies and analyses from a variety of subject areas including business and finance, medicine and pharmacology, ecology and the environment, energy, communications and media, transportation, work, family and leisure.
Newest articles
Lighting up the future
New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…
Researchers crack sugarcane’s complex genetic code
Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….
Evolution of the most powerful ocean current on Earth
The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….