Basically the patent describes a system where a user will have to snap a photo of themselves to prove that it is them before the device unlocks. It sounds a bit troublesome since using your fingerprint is a lot faster than firing up your camera and snapping a photo, but it is possible that it might be used as a backup verification tool, or maybe used in two-step verification processes.
It should be noted that this isn’t the first time Apple has demonstrated interest in facial recognition. Back in 2010, the company acquired Swedish firm Polar Rose who were known for their facial recognition tech. In fact it is possible that the facial recognition features in Photos and Photo Booth might have been courtesy of Polar Rose’s technology.
In any case given that this is a patent, there is no telling if and when Apple plans on implementing it into its products, although if they were to do that, they wouldn’t be the first. Google has attempted a similar feature before on Android, and recently MasterCard has announced a similar security feature which could be used to authorize payments.