NIST report on iris aging flawed: researchers

The release notes that Bowyer and Ortiz also pointed to methodological errors in the regression analysis used in the IREX VI report. One is that the data set used in the IREX VI report is “truncated,” meaning that all data points with a value above a threshold were deleted. The IREX VI regression analysis did not take account of this, resulting in an estimate for iris aging that is biased to be lower than it should be in reality. A second error is that the IREX VI report used one result of its regression analysis, taken “out of context,” to represent the effect of iris aging, when in fact the effect of aging may be present in several results in the IREX VI regression model. This could also result in an estimate of iris aging that is smaller than it is in reality.

A third error is that the data set used in IREX VI is a mixture of data points resulting from first, second, and third attempts at iris recognition in the border-crossing application, and this mixture could introduce bias that caused the estimated effect of iris aging to be smaller than it is in reality.

Bowyer and Ortiz presented a list of suggestions for improving a revised IREX VI report. The suggestions include obtaining a new version of the data set used in the analysis, and using regression analysis methods appropriate to the data set.

The release also notes that Notre Dame research has played a role in previous IREX reports issued by the NIST. For instance, previous Notre Dame research on the effects of varying pupil dilation on the accuracy of iris recognition is discussed in the IREX I and the IREX III reports (for Bowyer’s earlier criticism of the notion of iris stability, see “New research raises questions about iris recognition systems,” HSNW, 13 July 2012; and “Aging process confounds iris recognition biometrics,” HSNW, 31 May 2012).

Bowyer is the Schubmehl-Prein Professor and the chair of the Department of Computer Science and Engineering at the University of Notre Dame, as well as co-editor of the Handbook of Iris Recognition. Ortiz is a Ph.D. candidate in Notre Dame’s Department of Computer Science and Engineering.

— Read more in Kevin W. Bowyer and Estefan Ortiz, “Making Sense of the IREX VI Report,” Computer Vision Research Lab Technical Report, 23 December 2013; Samuel P. Fenker and Kevin W. Bowyer, “Analysis of Template Aging in Iris Biometrics” (paper presented at IEEE Computer Society Biometrics Workshop, 17 June 2012); see “Iris template ageing debate rolls on…,” Planet Biometrics (1 February 2014); Duncan Graham-Rowe, “Ageing eyes hinder biometric scans,” Nature (25 May 2012); and Duncan Graham-Rowe, “Ageing irises could confound biometric checks,” New Scientist (4 August 2010); and see P. Grother et al., IREXVI: Temporal Stability of Iris Recognition Accuracy, NIST Interagency Report 7948 (NIST,24 July 2013)