@EngrStudent the card does not necessarily contain information about the face. The pasta face ID was just an example. It could be any id card. What I am trying to say is that, what needs to be detected, is something that is pasted, or photoshoped.
I think that this is like a "weighted coin" where when it is near 50/50 it takes fewer samples to be sure about the weighting, but when it is near 100/0 it takes more samples to get to the same level of confidence. In our case that may be a measure of contiguous area, or pixels.