Apple Introduces Face ID with the iPhone X

Apple announced the iPhone X (pronounced “ten”) on September 12, 2017 at the Steve Jobs Theater — the first event at the new Apple Park campus in Cupertino — pricing it at $999 for 64 GB and $1,149 for 256 GB. The iPhone X replaced the physical Home button (present on every iPhone since 2007) entirely, enabling a 5.8-inch OLED Super Retina display (2436×1125, 458 ppi) that covered almost the entire front face of the device with a notch at the top for the TrueDepth camera system. The TrueDepth camera array comprised seven components: a dot projector (projecting 30,000 invisible infrared dots in a structured pattern onto the user’s face), an infrared camera (capturing the distortion of the dot pattern to build a precise 3D depth map), a flood illuminator (illuminating the face with IR light to enable recognition in the dark), a 7MP visible-light front camera, an ambient light sensor, a proximity sensor, and a speaker. The system worked in darkness where no 2D camera could function, and Apple quoted a false-acceptance rate of 1 in 1,000,000 for Face ID versus 1 in 50,000 for Touch ID — a 20× improvement in the probability of a random person’s face unlocking the phone.

Face ID processing occurred on the A11 Bionic chip (TSMC N10, 6-core CPU with 2 high-performance Monsoon cores + 4 efficiency Mistral cores, first Apple chip to include a dedicated Neural Engine running at 600 GOPS). The neural engine ran the face recognition neural network in real time — comparing the captured IR depth map against the enrolled face model — with the resulting match decision and all biometric templates stored exclusively in the A11’s Secure Enclave (a separate coprocessor that the main CPU and iOS never access directly). The biometric data was never sent to Apple’s servers. Face ID adapted to appearance changes (glasses, beard growth, aging) over time by updating the stored model when a successful unlock followed a failed attempt confirmed with the passcode. The TrueDepth system also powered Animoji — 12 animated emoji characters (ghost, poop, robot, alien, unicorn, and others) that mapped the user’s facial expressions to the character in real time using the 52 facial muscle points tracked by the depth sensor.

The removal of the Home button required replacing the iPhone’s entire gesture vocabulary: pressing the Home button to go to the Home screen became a swipe-up from the bottom edge; double-pressing Home for the app switcher became a swipe-up and pause; pressing Home while locked to see notifications became raising the phone or tapping the screen (raise-to-wake and tap-to-wake, also new in iOS 11). These gestures had to be reliable and fast enough that Face ID authentication and navigation together felt no slower than Touch ID + Home button on prior iPhones. In practice, Face ID authentication typically completed in under 0.8 seconds under good lighting. The iPhone X’s OLED display was supplied by Samsung Display (Apple’s first iPhone OLED after years of IPS LCD) and required True Tone (adaptive white point from ambient light sensors) and a new display calibration pipeline, since OLED’s different color rendering under varying conditions is perceptible and required software compensation across the full 10-bit color gamut for accuracy.