Hi Douglas,
AFAIK face detection function is limited to discover the eventual presence of faces in the camera view. For each face it records eyes center coordinates and mouth coordinates (or at leat what it believes are eyes and mouth) along with a confidence level score.
Face recognition is a whole another story. I presume, due to performance reasons, it's based on a kind of hash of the image under detection to be then compared to previous hashes stored in a DB.
Maybe you could searc for some facial recognition algorythm and/or API/SDK.
Umberto