How come face unlock is so fast on some phones, such as OnePlus5/6, Huawei mate 10?

[HelloAndoridWorld]

When I tested, it almost unlocks instantly, it is very like less than 0.4 second.
Then how do they by pass the hardware limitation? Is better hardware applied or there are some tricks which users are not aware of.

Unlock time = (1) time to wake up camera from sleep mode and send image to unlock algorithm + (2) unlock algorithm running time

For mid-tier phone camera per my test time, the (1) part only will take more than 0.5 second, let alone plus unlock algorithm running time.

Do anyone have insights or details about their opening camera time and algorithm running time, how could these phones can do this so fast? Thanks in advance.

 

[Rukbat]

First, who says that the face unlock software is sleeping? Second, the fewer points it checks, the faster the algorithm. I'd rather have it take a second and not recognize me if I'm frowning (unless I also saved a "face" with a frown). Too fast a response can mean a response to too many faces. It's the same with fingerprints or any other algorithm (for anything) - the looser the algorithm, the faster it is, but the less secure it is.

 

[jontalk]

I just picked up a nearly new 5T a few days ago and after setting it up, find both the face lock and finger print scanner to be lighting fast. Curious if you're running Android 9.0.4 like mine is. I LOVE this phone..battery life is astounding too!