Your phone fires 30,000 infrared dots at your face every time you unlock it.
But how does this light recognizeβ¦your face?
Take a quick look at your phone, specifically the black notch toward the top, near the camera.
Apple calls this system TrueDepth.
Eight components packed into that little black notch, all firing in the fraction of a second it takes you to glance down.
One of those components: the dot projector.
Itβ¦projects dots. 30,000 in a fraction of a second, every time you need to open your phone.
So FaceID isnβt taking a picture of your face. It's building a 3D map of it.
The dot projector casts 30,000 infrared dots across your features, and because your face has contours, those dots distort in predictable ways.
The infrared camera reads that distortion and reconstructs the geometry of your face in three dimensions.
Remember when you had to roll your head around during phone setup? The 3D model gets compared to the mathematical face print you created during setup.
This process uses a TON of data, but it happens so fast.
How?
Apple built a dedicated chip specifically to run this.
The Neural Engine inside the A-series processor handles the face-matching math at a speed and security level the main CPU couldn't manage alone.
And your face data never leaves your device.
It lives in something called The Secure Enclave [*oooooh, ahhhh*], which is an isolated processor that even the operating system can't read.
This system has an error rate of roughly 1 in 1,000,000. Touch ID is 1 in 50,000.
All of that, before you've finished picking up your phone!