KGI on Apple iPhone "Face ID" Internals

AppleInsider quotes KGI analyst Ming-Chi Kuo on the oncoming iPhone "Face ID" design. It employs 4 cameras: a regular front camera, structured light 3D camera and proximity ToF sensor:

"According to Kuo, Apple's system relies on four main components: a structured light transmitter, structure light receiver, front camera and time of flight/proximity sensor.

Kuo points out that structured light transmitter and receiver setups have distance constraints. With an estimated 50 to 100 centimeter hard cap, Apple needs to include a proximity sensor capable of performing time of flight calculations. The analyst believes data from this specialized sensor will be employed to trigger user experience alerts. For example, a user might be informed that they are holding an iPhone too far or too close to their face for optimal 3D sensing."