THINK ABOUT THE different ways you can unlock your phone. For a while, we stuck with the humble PIN, a password if you’re using a laptop, and recently fingerprint scanning has been in vogue with many high- and mid-range devices.

Now you can add iris scanning to the list. If you own a Surface Pro tablet or Microsoft Lumia device, it’s something you would have come across before, but Samsung has brought it with the Galaxy Note 7 (which was announced earlier today) and it’s reasonable to assume future phones will include it too.

So how does it work? It’s mainly down to an infrared scanner which scans the iris – the coloured part of your eye – to authenticate your identity. This can be used to unlock your phone and other secure features instead of using a PIN or password.

The Lumia 950, which was released late last year, included an iris scanner.

The hardware required uses near-infrared light (which you don’t see) to take a clear picture of a person’s iris. Since near-infrared light turns a person’s pupil black, it means it’s easy for the phone to pick out the pupil and iris and can identify unique patterns.

The reason it’s seen as a more accurate method than fingerprints is because the iris is protected by the cornea (a transparent front coating) while its pattern remains unchanged for most of a person’s life.

A small drawback is you need to hold the phone relatively close to your face (25 – 35cm in the case of the Note 7) to unlock properly.

Iris scanning shouldn’t be confused with retina scanners, however, which scan the blood vessel patterns at the back of your eye. Such a system would require more advanced technology whereas iris scanners use existing camera technology alongside an infrared light.

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