Facial recognition to open a pet door

Oreilly’s Make:blog had a very interesting comment on webcam uses. Interestingly enough, I have toyed with exactly the same uses but not to the scale that this project has started.
The Flo Control project uses a webcam to do facial recognition of the family cat. If there is a comparison match of the kitty and kitty isn’t bringing her dinner into the house, then the door unlatches and the kitty is let through. If there is no match, then the door remains locked.
If you have some time, a spare computer and looking to build a fun project for the family pet, this would allow a more sanitary environment for your family without having your pet’s friends party down in your house also.