I'm writing to ask if anyone here knows about (or has been approached by the Home Office about) the practicability and/or problems of Iris-pattern recognition for albino eyes.
I haven't been approached by the Home Office but I thought I'd have a look at the issue, as it's somewhat interesting.
First, albinism affects around 1 in 17,000 persons. This is greater than the proportion of persons with aniridia (lack of iris, which renders iris recognition ineffective), which affects around 1 person in every 56,000. Thus, any problems affect only a very small minority of persons. That, however, does not mean health and safety problems and biometric performance problems should be ignored - though there may well be more pressing problems that rightly deserve greater and more immediate attention.
Concerning aniridia, the solution is to use other biometric modalities, such as fingerprint, hand geometry, hand vein patterns, etc.
In fact, multi-modal and multi-instance (ie 2+ fingerprints) biometrics are required to provide adequate performance for Detection of Multiple Applications (DMA). So the availability of multi-biometrics is not just a requirement for those without irises.
While iris scanning is probably the best system of biometrics available it is by no means perfect (pace Prof. Daugman). After some harassment, the government has already acknowledged that it has problems with picking up patterns in heavily pigmented eyes, and claims to be re-calibrating the systems to cope better with black people.
There are techniques in statistical pattern matching, well-known to experts in the field, concerning recognition score normalisation for each enrolled person. There is also even better stuff, that people like me have been working on, that is perhaps not so well known.
There are, with albinos, also sometimes the problems of Nystagmus (irregular rapid movement of the eyes back and forth) and Strabismus (muscle imbalance of the eyes leading to "crossed eyes" or "lazy eye" (thanks Wikipeadia
). Both of these would adversely affect capture of iris images, except with more expensive equipment that uses video capture rather than still image capture of posed images.
But how about the reverse? How well does the system work on the smaller minority lacking pigment?
Iris recognition does not (so I understand from John Daugman) work for those with aniridia.
For those with less pigment in the infra-red range of wavelengths, there will very likely be lower performance. However, I understand that that blue eyes have more variability and contrast than brown, even though they have less melanin pigment.
I don't know about albino eyes. However, it is almost certainly better to exploit what discrimination there is between their irises than to ignore it, given that the equipment would be in place for the other 99.9941% of the population. This is certainly the case for DMA. The case for using iris at Points of Use (PoUs) for personal identity verification (with its non-zero capture time) of those with albinism would need to be made specifically for each PoU, or PoU type, on the basis of a full security assessment.
The illumination used rarely causes discomfort and is not known to be injurious to normal eyes, but is this still the case for albino eyes.
On this, it is worth noting that iris recognition uses low power near infra-red illumination from Light-Emitting Diodes (LEDs). John Daugman
Monochrome CCD cameras (480 x 640) have been used because NIR illumination in the 700nm - 900nm band was required for imaging to be invisible to humans.
Thus, the NIR illumination is not visible to humans; it therefore seems most doubtful that it is a problem for albinos. That is unless they have additional sensors to those in non-albinos, rather than more sensitive sensors to the same visible wavelengths.
However, this is not certain. We can go a little further into this without great expense. Acquire an albino volunteer and subject him to NIR illumination from a typical TV remote control unit. I've just done this to myself and could not see or feel anything, even at a range of about 2 inches; this was from 2 different IR controls, both known to be working immediately before and afterwards. However, it would be prudent to start at a fair distance, just in case other people do have greater sensitivity than me.
Typical TV/audio IR controls work at around a wavelength of 940nm (http://en.wikipedia.org/wiki/Image:Control-remote-spectrum.png
), which is greater than the 850nm and 900nm, which is, I understand, most typical of iris recognition.
However, I think this sort of experiment might go some way towards identifying whether there is a health/safety problem for albinos, even if it does give firm confirmation that there is no problem, through the wavelength difference of around 10%.