Biometrics & Security

Tutorial 11

• 1 (a) Why multi-biometrics? (P13: 3-6)

• 1 (b) What kinds of fusions we can take?

• 1 (c) Please explain three fusion modes in P13: 12.

F a c e

F in ge rp rin t

C la s s 1 ,2 ,...,N

C la s s 1 ,2 ,...,M(M < N )

C la s s X

F a c e

C la s s 1 ,2 ,...,N

F in ge rp rin t

C la s s 1 ,2 ,...,N

C la s s 1 ,2 ,...,M(M < < N )

C la s s 1 ,2 ,...,M(M < < N )

C la s s X

S e r ia l M o d e P ar r alle l M o d e

C la s s 1 ,2 ,...,N

C o a rs e F e a tu re(fa c e ; finge r;fa c e & finge r)

C la s s 1 C la s s 2 C la s s ... C la s s M(M < < N )

C la s s 1 1 C la s s 1 2 C la s s 1 X C la s s 2 1 C la s s 2 2 C la s s 2 X

F ine F e a tu re(fa c e ; finge r;fa c e & finge r)

F ine F e a tu re(fa c e ; finge r;fa c e & finge r)

F ine F e a tu re(fa c e ; finge r;fa c e & finge r)

F ine F e a tu re(fa c e ; finge r;fa c e & finge r)

C la s s M 1C la s s M 2 C la s s M X

H ie r ar c h ic a l M o d e

• 1 (d) What difference between biometric uni-modal and biometric multi-modal? (P13: 13-14)

• 2. There are four fusion levels defined in P13: 15. Could you give the corresponding structure of each fusion level?

• 3. Some fusion functions are given in both matching and decision level (P13: 25; 32-34). Please understand their math definitions.

M a tc hingM o d u le 1

M a tc hingM o d u le 2

M atc hingS c o re 1

M atc hingS c o re 2

F u s io nM o d u le

D e c is io nM o d u le 1

D e c is io nM o d u le 2

D ec is io nS c o re 1

D es c is io nS c o re 2

F u s io nM o d u le

Fusion = Score1 + Score2 or = Score1 x Score2 or = Max (Score1, Score2) or = ……