How does a system differentiate between a legitimate user and a 'presentation attack' if the attacker is using a high-resolution 4K screen to display a target’s face?

A system stops a high-resolution screen from tricking it by using something called liveness detection, which checks if the person in front of the camera is actually alive. Even a 4K screen is just a flat image that does not act like a real human face. The system looks for small physical clues that a photo or video cannot fake. One way is to che....