Fingerprint Minutiae Matching Algorithm using Distance Histogram of Neighborhood

1. Fingerprint Minutiae Matching Algorithm using Distance Histogram of Neighborhood Presented By: Neeraj Sharma M.S. student, Dongseo University, Pusan South Korea

2. Abstract • Paper proposes a novel approach for matching of minutiae point in fingerprint images. • The key concept used in the approach is the fact that the neighborhood properties for each of the minutiae points remains same in fingerprint images. • One of those characteristics is pair wise distance histogram that we have used in this algorithm. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

3. Introduction • Fingerprints are most useful biometric feature in our body. • Due to their durability, stability and uniqueness fingerprints are considered the best passwords. • In places of access security, higher degree authentication, and restricted entry places fingerprints suggests easy and cheap method. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

4. Biometric Modalities CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

5. Market Capture by different Biometric modalities CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

6. Previous Work • Fingerprint Identification is quiet mature area of research. Its almost impossible to describe all the previous approaches in a short time here. • The previous methods closely related to this approach are by Park et al.[2005] and Wamelen et al.[2000]. • Park et al. from used pair wise distances first ever to match fingerprints in their approach before two years. • Wamelen et al. gave the concept of matching in two steps, Local match and Global match. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

7. Enclosure Singular points Bifurcation Island Texture Different Features in a Fingerprint Ridge Ending CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

8. High level description of algorithms in FVC 2004 CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

9. Feature Extraction with CUBS-2005 algorithm Developed by SHARAT et al Minutia features Extraction of minutiae Image skeleton Gray scale image CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

10. Problem Simulation Input Pattern Template • The input fingerprint of the same finger seems to be different while taken on different times. • There may be some translational, rotational or scaling changes, depending upon situation. • Our aim is to calculate these changes as a composite transformation parameter “T”. • The verification is done after transforming the input with these parameters, new transformed pattern should satisfy desired degree closeness with template pattern. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

11. Minutiae matching-Aligning two point sets Template Input CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

12. Process Steps • The algorithm runs in two main steps:- (i) Local matching (ii) Global matching In local matching three stepwise calculations are there: • Calculate “k” nearest neighbors for each and every point in both patterns. • Calculate histogram of pair wise distances in the neighborhood of every point. • Find out the average histogram difference between all the possible cases. • Set the threshold level of average histogram difference • Compare the average histogram differences with the threshold level. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

13. Start Point pattern “P” stored in database pattern “Q” is taken that is to be matched with “P” Select a local point and it’s “k” nearest neighbors in patterns P Select a local point and it’s “k” nearest neighbors in patterns Q Make pair wise distance Histogram Average histogram difference < Threshold level No Calculate and store transformation parameter All point’s in pattern p is examined No Iteration algorithm to calculate final Transformation Parameter End Flow Chart CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

14. Calculation of “k” Nearest neighbors (Local match) • For the given input fingerprint pattern and the template pattern, calculate “k” nearest neighbors in order to distances. • Here k is a constant can be calculated with the formula given by wamelen et al.(2000) CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

15. P1n1 P1n2 P1n3 P1 P1n1 P1n3 P1n4 P1n4 P1n5 P1n5 P1n4 P1n3 P1n3 P1n5 P1n2 P1n4 P1n4 P1n5 P1n5 Histogram Calculation (Local Match) • Histogram of pair wise distances in their neighborhood for each and every point is calculated here. It describe the variety of distances of particular point in its neighborhood. • Here for one point “P1”; P1n1,P1n2,P1n3,P1n4,P1n5 are five nearest neighbors. • Note: step size is 0.04unit, here. P1n2 CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

16. Average Histogram Difference and Threshold Setting (Local Match) • To calculate average histogram differences for two points, first subtract the their histograms. It comes in a form of matrix. To calculate average, just normalize it on corresponding scale. H1=[4 2 0 0 2 0 1 2 3 1] H2=[1 3 2 5 0 0 2 3 0 1] H1- H2=[3 -1 -2 -5 2 0 -1 -1 3 0] Average histogram diff.(ΔH avg)=(1/10)*Σ(| H1 - H2 |i) • Setting of threshold depends on the size of point pattern. Larger the number of points, smaller the threshold count. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

17. Transformation Parameter calculation • On the basis of histogram differences, we can make decision on their local matching. Then the transformation parameter is calculated in the following way. Here “r” represents the corresponding Transformation Parameter. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

18. Axial Representation of all Transformation Parameters after Local match • Three axes represent the translational (in both x& y direction), rotaional and scale changes. • The most dense part in graph represents the correct transformation parameters only. We need to conclude our results to that part. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

19. Iteration Algorithm • Iteration method is used to converge the results towards dense part of the graph. • For applying this method we need to calculate mean and standard deviation of the distribution. • In graph all the transformation parameters are present, calculated after local matching step. • The mean for this distribution is presented by the “triangle” in centre. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

20. Result after first iteration • In the graph, black star is describing the mean for the distribution. • After one iteration step some of the false transformation due to false local match has removed. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

21. Result after second iteration • After second iteration, graph converges more towards the dense area. • Black star is the mean point for this distribution shown here. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

22. After third iteration • Performing iterations to converge the result, gives the distribution having least standard deviation. • Black star in this graph is the desired transformation parameter i.e. “r” CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

23. Verification by transforming the template with calculated parameters Transformed With “r” Template Pattern in Database Transformed version with Parameter ”r” Verification by Overlapping CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

24. Experimental Results(With random generated data) CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

25. Results contd… CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

26. Results with real and random fingerprints • The algorithm was tested on both randomly generated point pattern and real data base. • The results shows the correct identification in more than 98.87% cases with random data. • For real fingerprints we tested the method on some FVC 2004 samples. In most of cases performance was found satisfactory. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

27. Limitations • This algorithm is very much dependent on accuracy of feature extraction method used for minutiae determination. • If feature extraction is not done correct then, results can have errors or false acceptances. Which effects performances and accuracy a lot. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

28. Future work • This method is still dependent to some other algorithm for feature extraction. • First task is to develop a method for feature extraction from fingerprints. • Other thing to enhance is, its performance mainly on real fingerprint data. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

29. Advantages of the Method over others Proposed earlier • This algorithm undergoes two steps, so accuracy is good and false acceptance rate is low. • Calculation is less complex with comparison to others, as histogram is a basis to select the local matching. While in other Random algorithms a lot of calculation is done for local match coz lacking in any basic attribute. • Algorithm doesn’t need very complex system to be implemented for practical/commercial purpose. So compatible to most of systems in use already. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

30. Shortcomings • Dependency on an efficient feature extraction scheme. • Histogram differences should be calculated in a better way (Still to think over that…). CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr

31. Thanks for your kind attention. CGIV 19SEP07 Presented by:neeraj@dit.dongseo.ac.kr