1. 1 Biometric template selection and update: a case study in fingerprints Source:Pattern Recognition, Vol. 37, 2004, pp.1533-1542 Authors: Umut Uludag, Arun Ross and Anil Jain Speaker: Shu-Fen Chiou( 邱淑芬 ) Date: 2004/11/04

2. 2 Outline Introduction Proposed method Experimental results Conclusions Comment

3. 3 Introduction A typical biometric system operates in two distinct stages: Enrollment stage. Authentication stage. In order to account for variations in the biometric data of a user, multiple templates corresponding to each user may be stored.

4. 4 Problem partial overlap different sensorsa period of 6 weeks exhibiting difference in moisture content Result in inferior performance

5. 5 Solve problems Store multiple templates Consider: number of templates storage computational Efficient function: automatic select templates

6. 6 Proposed method Template selection DEND MDIST Template update BATCH-UPDATE AUGMENT-UPDATE

7. 7 Template selection N fingerprint images Select K templates (K<N) Store templates in database Selection: Random selection Systematic selection Better performance

8. 8 Template selection DEND 1234512345 1 2 3 4 5 50 150 200 100

9. 9 Template selection

10. 10 Template selection MDIST 1234512345 1 2 3 4 5 Avg.

11. 11 Template Update BATCH-UPDATE: newly acquired data. AUGMENT-UPDATE: after augmenting the new data set with current template set.

12. 12 Experimental results DEND selection

13. 13 Experimental results MDIST selection

14. 14 Experimental results

15. 15 Experimental results

16. 16 Conclusion A systematic template selection procedure results in better performance than random template selection.

17. 17 Comments 利用 DEND 的方法分完群後, 計算群裡面的 template 數量大小，加 上權重的觀念, 加快比對的效率。 經過一段時間測試，以權重而分的 template 被找到的次數再調整 template 的權重。 (a) weight=3 (b) weight=4 (c) weight=2 (d) weight=1 (e) weight=1

18. 18 Comments 動態決定群的數量