Controlling access to a given building or verifying a person's identity on site is key to providing a secure environment. That said, end users will not be wanting to install a system that requires lengthy (and potentially dangerous) procedures and which is subject to high error rate. So what's the answer? We examine the science behind biometrics, and reviews one of the latest systems designed to provide secure, 'one glance' access control.
"Yes, we're all individuals" shouts the crowd in unison in the celebrated Monty Python film The Life of Brian. Funny thing is, they were right... Despite uncanny resemblances, phenomena like identical twins and high degrees of similarity, we humans possess enough characteristics that differ for us all to be able to say that we are indeed unique.

Problem is, how do you prove that to be the case – or, more importantly, encourage a machine to recognise the differences? That's where biometric technologies come in.

Biometrics originally referred to the use of statistical and mathematical models applicable to data analysis problems in the biological sciences (eg analysis of data from agricultural field experiments to compare the yields of different varieties of wheat, for example). More recently, though, the term has been used to refer to the automatic identification of an individual based on their physiological or biological traits.

A biometric system is essentially a pattern recognition system which makes a personal identification by determining the authenticity of a specific physiological or behavioural characteristic possessed by the user. Various types of system are now in use, of course, including facial recognition, fingerprint matching, hand geometry and retinal and iris scanning.

Of all these systems, iris scanning and recognition is the most accurate, stable and non-invasive form of authentication technology. The iris – ie the coloured ring of tissue that surrounds the eye's pupil – is the most mathematically distinct feature of the human body. It's stable, and remains unchanged throughout your life. It's claimed that the patterns contained in the human iris are more distinct than DNA (identical twins have the same DNA, but different iris patterns). The iris pattern will even differ between a person's left and right eye.

In the mid-1990s, Dr John Daugman OBE of Cambridge University developed and patented the iris recognition systems that are now owned by Iridian. Iris identification uses a high resolution camera to take a picture of the eye. It doesn't require any form of physical contact, and works from a comfortable distance away. Once the picture has been taken, the iris pattern is processed and encoded by the software into a 512-byte IrisCode record (which is immediately encrypted, and cannot be reverse-engineered).

The IrisCode record is based on 244 independent variables – or 'degrees of freedom' – that are measured for each iris. Other biometrics (such as fingerprint recognition and hand geometry) typically measure less than 60 independent variables. The IrisCode record is stored and used for recognition in any transaction when a live iris is presented for comparison. Identification time averages about one-to-three seconds.

At-a-glance recognition
Working with Iridian software, forward-thinking security systems manufacturer Panasonic has just devised a 'one glance' automatic iris recognition system that's said to eliminate the problems of undue hold-ups in access procedures, at the same time guaranteeing smoother and more secure entry management.

As its name implies, the 'one glance' system simply involves the individual concerned looking at a wall-mounted camera unit comprising unique technology to automatically detect a person's presence and capture an image of iris patterns. The specialised security camera takes an image of the iris and generates a comparison against previously stored patterns. Pattern matching and identification takes around three seconds.

Interestingly, the system has been adapted for use with three cameras, such that the first of them – a wide-angle camera – recognises the face while a second (a telephoto) zooms in on the iris to capture its image and begin the identification process. The third camera unit provides additional security, with the inclusion of a high resolution colour CCTV camera designed for facial capture or integration into an existing CCTV system.

The IrisCode record is based on 244 independent variables – or ‘degrees of freedom’ – that are measured for each iris. Other biometrics (such as fingerprint recognition) typically measure less than 60 independent variables

With Health and Safety issues very much in mind, it's important to point out that the amount of infrared illumination used in the scanning process is very weak, enabling the system to pass all current eye safety legislation.

Iris recognition technology is pretty much ideally suited for high security applications because of its extremely low error rate (typically less than one in 100,000) which ensures really precise individual identification. Confusion with another individual is said to be virtually impossible.

As well as providing probably the ultimate in high security, iris recognition can also offer a number of other significant benefits for the end user. For one, it obviates the need for ID cards and passwords, providing huge time and cost savings in password maintenance alone.

Easy and quick system set-up is bolstered still further by the fact that biometrics networks may be expanded comfortably to accommodate a growing user group.

Taking iris scanning to PCs
Taking iris recognition technology a step further, Panasonic has also developed a PC Webcam that's capable of identifying the user from his or her iris pattern.

The BM-ET100 – otherwise known as the 'Authenticam' – eliminates the need for any passwords. The 'biometric key' employed is far more secure than that, as it cannot be forgotten, stolen, lost or forged, and is impossible to hack or guess.

Easy to install, the Authenticam is simply plugged into the USB port on the PC, and the camera takes a picture of the iris to match it against a previously stored code. The small camera may be located on a desktop. In addition, the device can also be used for image capture, video e-mail and video conferencing.

With both of these applications, it's important for the end user not to confuse iris scanning with retina scanning – a confusion that has largely been driven by the movie industry! Retina scanning technology uses a laser to scan the blood vessels at the back of the retina. It can be highly intrusive, and there have been cases where eyes have been damaged as a result.

Hollywood would also have us believe that if we did in fact manage to extract someone's eye and presented it to the machine, it would trick the system. Afraid not. It must be a 'live' iris with blood flowing through the capillaries that is presented for comparison.