For biometric authentication purposes, the iPhone 13 models use Face ID, the facial recognition system that was first introduced in 2017. Face ID components are housed in the TrueDepth camera system in the display notch, which is smaller this year.
Face ID is used across iOS tasks for unlocking the iPhone, allowing access to third-party passcode-protected apps, confirming app purchases, and authenticating Apple Pay payments.
Face ID works through a set of sensors and cameras. A Dot Projector projects more than 30,000 invisible infrared dots onto the surface of the skin to create a 3D facial scan that maps the curves and planes of each face, with the scan read by an infrared camera.
The facial depth map is relayed to the A15 chip where it is transformed into a mathematical model that the iPhone uses to authenticate identity. Face ID works in low light and in the dark, and with hats, beards, glasses, sunglasses, scarves, and other accessories that partially obscure the face.
For face masks, which do not work with Face ID, there’s an “Unlock with Apple Watch” feature for convenience. Unlock with Apple Watch allows iPhone users to take advantage of an unlocked and authenticated Apple Watch as a secondary authentication measure to unlock their devices when wearing a mask. It can’t be used to authenticate Apple Pay or App Store purchases, and it can’t unlock apps that require a Face ID scan. In these situations, a mask needs to be removed or a passcode needs to be used instead.
