As revealed by Patently Apple, Apple has recently filed patents for locking and unlocking phones using facial recognition software. The patents aren’t just about recognizing faces as an alternative to passwords, they also covers the use of movement patterns for locking the device, filtering out unintended movement, and using the camera to distinguish between users (as well as detecting when a child is holding the device).

Apple’s patent would let your phone watch out for itself.

Not only would this be a replacement for Apple’s current password based security system, but it could also be used to keep an opened device secure. The phone’s front could be set to take a facial recognition picture at a preset amount of time ‘idle’ to keep users with unrecognized faces from gaining unauthorized use of the device. Of course it may also be inconvenient if you need to briefly lend your phone out.

Keep in mind that just because a patent is filed doesn’t mean the design will see the light of day. While facial recognition has a lot of science fiction appeal, it might not be the ideal solution for unlocking your phone. For facial recognition to work, the camera needs decent lighting and the user’s face needs to be in the shot.

Apple’s algorithm for determining when to activate facial recognition and lock the device.

What’s may be of special interest is the patent mentions authorized users in plural. To this date, the iPhone, iPad, and iPod Touch have not officially included support for multiple user accounts. There was a (now outdated) Cydia tweak that offered a hacked together solution for multiple user accounts, and Apple did say they were ‘investigating’ multi-user support for iOS. Considering iOS 6′s deep integration with both Facebook and Twitter, the ability to quickly swap accounts is almost critical if you intend to share an iPad.

Would you prefer facial recognition over passwords? Share your thoughts in the comments section below.