Big Brother is growing up. Researchers at Carnegie Mellon University recently demonstrated an iris scanner capable of identifying a person at a distance of 40 feet.

In a series of tests, identity recognition software developed by scientists at Carnegie Mellon's CyLab Biometrics Center was able to identify unique patterns in a person's iris and match it to a name in a database using a live video feed honed on the eyes of the subject.

Imagine this: a police officer pulls a speeding car over. Before the officer has exited the car, iris scanning software has picked up the driver's eyes in the rearview mirror and matched the iris to an identity -- that of a potentially dangerous subject.

That's what happened during one of the CyLab's recent tests.

The technology works just like fingerprinting. Like a fingerprint, each person's iris is unique. Mathematical models can recognize the unique patterns in each. But while fingerprinting (or DNA testing) requires direct contact or extensive testing, iris scanning can be performed at a distance.

Imagine a slightly less threatening scenario: iris-recognition devices constantly scan a queue at the airport security checkpoint, minimizing wait time and screening out high-risk travelers.

But convenience and safety aren't always enough to make the general public comfortable with identity-recognition technologies. In a recent survey, researchers at the University of Oxford found that people remain uncomfortable with wireless (and human-less) biometric technologies.

"I feel negatively about a remote iris scan because I want there to be some kind of interaction between me and this system that's going to be monitoring me," one study participant explained.

Before the technology is employed in daily life, researchers say significant legal and public relations hurdles will need to be successfully navigated.