I asked this question because as I know, some devices that use similar technology with IR emitter and IR camera don't work in sunlight. They're Microsoft Kinect, Intel Realsense, Leapmotion... That happens because sunlight is a bigger IR source that overlap on IR light from IR Emitter, then makes the IR camera cannot get the correct dot images.
Before the iPhone implemented it, every fingerprint scanner I used either took forever or was miserably unreliable. I was skeptical iPhone's scanner could do a good job. It proved me wrong.
Similarly, every facial recognition technology I have used has either taken forever or was miserably unreliable. This time I'm not betting against Apple.
