In the future, there may be a new way of logging into your Apple gear like the iPhone or iPad. Apple has filed a patent app that outlines a way that the gadgets could log different users in using presence detection and face detection reports PatentlyApple. The cool part is that you could have multiple accounts on the devices and would need to do nothing to log into your account.
The patent has some snazzy line art with a stick figure walking up to the gadget. It outlines that the detection would look at skin tone, location of eyes and mouth compared to a reference image, and match the face with one in an image.
The presence detection could turn the device on as soon as you walk up. Together the device would turn itself off and on and log you into your user account just by you walking up to it. That sounds really cool.