Linear combinations of eigenfaces — images like the above — are the cheapest way to store and search photos of faces. Like if you want to computer analyse the faces of everyone at the Superbowl and see if there’s a terrorist.

All of the terrorists’ faces are saved in a database as like {11% Eigenface_1, 6% Eigenface_2, 1% Eigenface_3, …}. So the real face breaks down to just a list of percentages {11%, 6%, 1%, …}.

Articles on Eigenfaces: 1, 2, 3, 4, 5, 6  (sorry to reinforce the google hierarchy)

If you break the faces in the live Superbowl crowd CCTV’s into such a list of percentages, then you can have a computer do a search against known terrorists. (Imagine having the computer search pixel by pixel. It would be like, Hey, the top left of your head looks like the top left of a terrorist’s head! Whoops, that was just the soda machine.)

Final point. There is more than one way to mathematicise a face. Surface normal vectors are one way; the manifold limit of polygons is another; projection is another; and eigenfaces are another. Each way has you conceive of a face differently.

59 notes

1. mysilences reblogged this from isomorphismes
2. aakm612 reblogged this from isomorphismes and added:
This is what we learned today, except with dogs =]
3. facemachine reblogged this from isomorphismes
4. rispostesenzadomanda reblogged this from wahrscheinlichkeit
5. erlenmeyers reblogged this from isomorphismes
6. theducksnews reblogged this from proofmathisbeautiful
7. supercuddlypuppies reblogged this from proofmathisbeautiful and added:
math is neat ^_^
8. daisen-in reblogged this from proofmathisbeautiful and added:
Eigenfaces! You’re starting to see the importance of asymmetry to identifying faces in the bottom right hand eigenface…
9. symptoms reblogged this from proofmathisbeautiful
10. bparramosqueda reblogged this from proofmathisbeautiful
11. separate-integrate reblogged this from proofmathisbeautiful
12. irwannugroho reblogged this from proofmathisbeautiful
13. nostep reblogged this from proofmathisbeautiful
14. wahrscheinlichkeit reblogged this from proofmathisbeautiful and added:
I find this utterly fascinating.
15. gentleconsideration reblogged this from proofmathisbeautiful
16. celestial-aspirations reblogged this from proofmathisbeautiful
17. proofmathisbeautiful reblogged this from isomorphismes
18. moreartlessmatter reblogged this from isomorphismes
19. davidaedwards reblogged this from isomorphismes