Who was that masked man, anyway?

from here and here (image source)

It doesn't surprise me that face recognition systems can operate with less than complete faces, but if you keep obscuring more and more there comes a point at which the computers can no longer be said to be operating on facial data. I don't doubt that you can recognize someone by just their eyes (that's what iris recognition and retinal biometrics are all about) but I really don't think you can call it face recognition at that point. It's a different technology. A face recognition algorithm that tried to operate with that little data would be more appropriately called a face guessing algorithm because it would be guessing what the face looked like and then deriving the identity from that.