A 2D camera fails when corridor light changes. The module projects a structured-light pattern and measures depth, so it works at night with IR fill, in backlight, and against a photo held to the lens.
What it changes in practice
- Depth-based liveness — rejects photos and screens
- IR illumination for dark landings
- Sub-second match at 0.5–1.2 m
- 2 MP cat-eye in the same aperture
Honest limit: the silicon may be rated wider than the assembled lock. The cell and the display set the real range, which is why the face platforms are published at −20 °C to +40 °C.