An Australian researcher is developing technology that would let you use your eyes - or more specifically your iris - to unlock your PC, access secure buildings or open your front door.

Iris scanning technology exists in a number of applications but the researchers at Queensland University of Technology say there is one big hole in it: light. Lighting can change a person's pupil size and distort the iris pattern leading to false positive and negative identifications, researchers said. To overcome that flaw, Queensland researchers are developing technology to estimate the effect of the change in the iris pattern resulting from changes in lighting conditions.

"Every individual iris is unique and even the iris pattern of the left eye is different from the right. The iris pattern is fixed throughout a person's lifetime," said university researcher Sammy Phang.

"By using a high-speed camera which could capture up to 1,200 images per second it was possible to track the iris surface's movements to study how the iris pattern changed depending on the variation of pupil sizes caused by the light," Phang said. Results of tests conducted using iris images showed it was possible to estimate the change on the surface of the iris and account for the way the iris features changed due to different lighting conditions.

"It is possible for a pupil to change in size from 0.8mm to 8mm, depending on lighting conditions," she said.Ultimately the Queensland technology would be built into applications that could use the information to more securely grant access to a computer or a car.

A number of companies develop iris scanning technology, including IrisGuard , L-1 Identity, LG Electronics and IriTech.

Meanwhile, face recognition as a unique biometric is also growing slowly in certain corporate and consumer applications, but researchers at the University of Houston are trying to make the technology far more ubiquitous and secure: they want it to replace the dozens of personal identification numbers, passwords and credit card numbers everyone uses every day.

And in a twist to the biometric security story: If the fingerprint-smudged glass plates on biometric devices skeeve you out, Purdue University researchers have some good news for you: The devices aren't any germier than typical doorknobs.