NoahFace runs on a tablet mounted next to your door. You can configure it to identify people using a combination of facial recognition and other factors:
Facial recognition is a biometric factor, or "something you are", and is strengthened with the use of anti-spoofing or liveness testing technology.
PINs are an example of a "something you know" factor. On their own, they are a weak form of identification as they can be shared, but when combined with facial recognition they provide much stronger authentication.
One-Time Passcodes, the Google Authenticator, and Access Cards are examples of "something you have" factors. On their own, they are a weak form of identification as phones and cards can be lost, stolen, or shared, but when combined with facial recognition they provide much stronger authentication.
When all configured forms of identification are validated is the person considered to be authenticated. Only then are the access rules assessed, either by NoahFace or by your Access Control System.