The State-of-the-Art in Iris Biometric Cryptosystems
Andreas Uhl, Christian Rathgeb · InTech eBooks · 2011
In 1984 a photographer named Steve McCurry traveled to Pakistan in order to document the ordeal of Afghanistan’s refugees, orphaned during the Soviet Union’s bombing of Afghanistan. In the refugee camp Nasir Bagh, which was a sea of tents, he took a photograph of a young girl approximately at the age of 13. The portrait by Steve McCurry turned out to be one of those images that sears the heart, and in June 1985 it ran on the cover of National Geographic. The girl’s sea green eyes have captivated the world since then and because no one knew her name she became known as the “Afghan girl”. In January 2002, 17 year later, a team from National Geographic Television brought McCurry back to Pakistan to search for the girl with green eyes. When they showed her picture around Nasir Bagh, the still standing refugee camp, there were a number of women who came forward and identified themselves erroneously as the famous Afghan girl. In addition, after being shown the 1985 photo, a handful of young men falsely claimed the Afghan girl as their wife. The team was able to finally confirm her identity using the iris feature analysis of the Federal Bureau of Investigation (FBI), which matched her iris patterns to those of the photograph with almost full certainty (Braun, 2003). Her name was Sharbat Gula, then around the age of 30, and she had not been photographed since. The revealment of Sharbat Gula’s identity manifested the strength of iris recognition technologies. Figure 1 (a) shows the original image of her which was printed on the cover of National Geographic in 1985 and another portrait taken in 2002 which was used for identification. Iris biometrics refers to high confidence recognition of a person’s identity by mathematical analysis of the random patterns that are visible within the iris of an eye from some distance (Daugman, 2004). Figure 1 (b) shows a good-quality NIR infrared image of an human eye captured by an iris recognition device. In contrast to other biometric characteristics, such as fingerprints (Maltoni et al., 2009), the iris is a protected internal organ whose random texture is complex, unique, and very stable throughout life. Because the randomness of iris patterns has very high dimensionality, recognition decisions are made with confidence levels, high enough to support rapid and reliable exhaustive searches through national-sized databases. Until now iris recognition has been successfully applied in diverse access control systems managing large-scale user database. For instance, in the UK project IRIS (Iris Recognition Immigration System), over a million frequent travelers have registered with the system for automated border-crossing using iris recognition. IRIS is in operation on different UK 9