Comparing fft's to classify data.

Hello all,

I am trying to write a program that distinguishes notes by reading the fft of some test data and comparing it with a bank of data.

If you see the image i have linked below it is clear which of the two banked fft's (red and blue) match with my test data (green). I can see this, but how do i get matlab to make this comparison and produce this result.

Please note when i implement it i will have the fft of every note on a 6 string guitar saved as banked data.

http://tinypic.com/r/15e8ffm/6

P.s: i've touched on knnsearch but its all nonsense to me o.O any insights or alternatives regarding this? Thank you!

David.