Reconstructing Orientation Field From Fingerprint Minutiae to Improve Minutiae-Matching Accu

racy

9977003 吳思穎

Introduction

Tradition :

store the minutiae template in the database.-> include two step : 1. minutiae extraction 2. minutiae matching

This paper :

reconstructing fingerprint’s orientation field from minutiae and further utilizing it in the matching stage to enhance the system’s performance.

fusing the results of orientation field matching with conventional minutiae-based matching.

Fig. 1. Flowchart of the proposed algorithm.

• Section II : the algorithm of reconstructing

orientation field

• Section III : the algorithm of fingerprint

recognition by minutiae and

orientation field.

• Section IV : experimental results

• Section V : conclusion and discussion

The algorithm of reconstructing orientation field

• Interpolation

• Reconstruction Using an Orientation Model

Interpolation

Triangulation

Use Delaunay triangulation

Interpolation

Producing “virtual” minutiae using interpolation

(1)

(2)

2,2

,0 ,

ii

iii

otherwise ,

2

- and 2

,

otherwise ,

2

- and 2

,

3

1323

3

22

1

1321

1

if

if

Interpolation

Producing “virtual” minutiae using interpolation

(3)

(4)

3133221

21

2133221

13

1133221

32p

dddddd

dd

dddddd

dd

dddddd

dd

2

3 ,-2

0 ,

02

- ,

pp

pp

pp

p

Reconstruction Using an Orientation Model

• Polynomial model

• Reconstruction the orientation field using polynomial model

,sin2i,cos2

,,,

yxyx

yxIMiyxREyxU

yx,sin2-Py,x,PIyx,cos2-Py,x,PRmin arg P,Pyx,

202

201

P2P1,

*2

*1

Fig. 5. Results of the proposed algorithm: (a) virtual minutiae by interpolation (the bigger red minutiae are “real,, while the smaller purple ones are “virtual,);

(b) the reconstructed orientation field.

Fig. 6. Comparison result I: (a ） minutiae image with a wrong direction (marked with ellipse ） ; (b ） the corresponding poor result by interpolation (marked with ellipse ) ;(c ） the corresponding good result by the proposed IM method.

Fig. 7. Comparison result II: (a ） minutiae image with a sparse region (marked with ellipse ） ; (b ） the corresponding poor result by model-based algorithm (marked with

ellipse ） ; (c ） the corresponding good result by the proposed IM method.

The algorithm of fingerprint recognition by minutiae and orientation field.

ji,

ji,N

1BA,s

ji,-ji,ji, BA0

• experimental results

• conclusion and discussion