000-985/003/4(06)08 003 Jornal of Software Vol4, No6 +,,,, 3 (,0093) (, 5000) 3 (, 3603) A Method for Singlarity Detection in Fingerprint Images TAN Tai-Zhe +, NING Xin-Bao, YIN Yi-Long, ZHAN Xiao-Si, CHEN Yn 3 (Department of Electronic Science and Engineering, Nanjing University, Nanjng 0093, China) (College of Compter Science and Technology, Shandong University, Ji nan 5000, China) 3 (Department of Compters, Fyang Normal College, Fyang 3603, China) + Corresponding athor: Phn: 86-5-359356, E-mail: tantaizhe@63net Received 00-07-06; Accepted 003-0-8 Tan TZ, Ning XB, Yin YL, Zhan XS, Chen Y A method for singlarity detection in fingerprint images Jornal of Software, 003,4(6):08~088 http://wwwjosorgcn/000-985/4/08htm Abstract: It is very important to detect singlarities (core and delta) accrately and reliably for classification and matching of fingerprints In this paper, a method for singlarity detection in fingerprint images is presented to improve accracy of the position and reliability of the singlarity Firstly, the singlarities are detected based on block images throgh shifting position of the whole image time after time at the same block size and the concentrative region of singlarities detected nder different positions is got and the centroid of the region is compted to gain the accrate position of singlarities Then, the reliability of singlarities detected above is determined with mltilevel block sizes In this method, the characteristics of the relative concentration of the position of singlarities detected throgh image shift and of the corresponding relationship of the singlarities detected with mltilevel block sizes are sed and the singlarities are detected accrately and reliably Experimental reslts show that the method performs well and it is robst to poor qality images Key words: fingerprint; singlarity; dividing into blocks with image shift; mltilevel block size : (core delta ),,,,,, Spported by the Natral Science Research Project of Anhi Province Edcation Office of China nder Grant No00KJ34 ( ) : (970 ),,,,,
: 083,,, : ; ; ; : TP39 : A [],, [~8],,,,, (delta ), (core ) (core delta ) Fig Example of core point Core Fig Example of delta point Delta VSSrinivasan NNMrthy [9], Asker MBazen [0] [],, Poincare index [3] delta core,,,, ;,,, (Poincare index ),, Poincare index 3 Poincare index Poincare index Kawagoe Tojo [3] O, (i,j) Poincare index :
084 Jornal of Software 003,4(6) N Ψ Poincare( i, j) = ( k), () ð k = 0 ð δ ( k), if δ ( k) < ð ( k) = ð + δ ( k), if δ ( k), ð δ ( k), otherwise δ ( k) = O ( Ψ ( i ), Ψ ( i )) Ο ( Ψ ( i), Ψ ( i)), x y x y i = i + ) mod N, (4) ( Ψ ) Ψ x(i Ψ y (i) NΨ i x y Poincare index /, (i,j) core, Poincare index /, (i,j) delta [5] [8] KKar Poincare index,,, Poincare index, :() ;() ;(3) Poincare index ;(4), x y,, Poincare index,, Poincare index,,,, ;,,,,, 3 (8 8), 4 5,, () (3) Fig3 Singlarities detected by block images throgh shifting position of the whole image time after time at the same block size (8 8) Fig4 Corresponding relationship of the singlarities detected with mltilevel block sizes Fig5 Corresponding relationship of the singlarities detected with mltilevel block sizes 3 (8 8) 4 5
: 085 :() ;() ;(3), Ratha [] m, W 0 W 0,W W,,W m W m ( W 0 =8,W i = W 0 (i+),i=0,,,m ) ST ij (i=0,,,m,j {0,,,n }) W i Wi STij = j, (5) n Wi W i,,n x y n (0 n W i,i=0,,,m ) W i W i, x y ST ij,,, x y ST ij, AKJain,LHong RBolle [3], 3, Singlar i, j,,i (i=0,,,m ),j (j {0,,,n n }) : (,v) Poincare index, Poincare index core delta core Poincare index, delta Poincare index 3 3, 6 7,,,v,v+,v,v+ +,v +,v+,v Fig6 Mask of detecting core point Fig7 Mask of detecting delta point 6 core 7 delta Poincare index Singlar, i j 3 (threshold i
086 Jornal of Software 003,4(6) ), { Singlar i, j i,j j,i=0,,,m,j=0,, } 3 ( m=4), ( 4 5 ),, 3 Core W m W m core, core Singla r m, W m 3 W m 3 core Singlarm, x Singlar m v x x, (6) Singlar Singlar, y Singlar m m v y y, (7) x W m W m core x,, Singlar, y m, W m W m core y, x y x y ( ) () W m 3 W m 3 core, core Singla r m v, W m 4 W m 4 core Singla r m w, W m W m core Singla r m W m 3 W m 3 core Singla r m v ( ) core core ( 5 ) Singla r m v Singla r m w Singla r m d, d = A Singlar m v x + B Singlar m v y + C, (8) A + B A = Singlarm 4, w y Singlar m y, (9) B = Singlarm, x Singlar m w x, (0) C = Singlarm, x A Singlarm y B () d < DisThreshold, () core Singla r m w core, DisThreshold core core, W m W m core Singla r m W m 3 W m 3 core, core core () W m 3 W m 3 core, W m W m core Singla r m, W m 4 W m 4 W m W m core,, core core core 3 Delta W m W m delta, W m 3 W m 3 delta W m 3 W m 3 delta, W m 3 W m 3 delta, delta, W m 4 W m 4 delta, delta delta m
: 087 3, ( 00,0, 0, 500dpi, 30 30,56, ZY0-B ) 40, Poincare index, Poincare index,,,,, 8, Poincare index Fig8 Examples of the singlarities detected 8, Poincare index,,,,,,, core, core,
088 Jornal of Software 003,4(6) References: [] Yin YL, Ning XB, Zhang XM Development and application of atomatic fingerprint identification technology Jornal of Nanjing University (Natral Sciences Edition), 00,38():9~35 (in Chinese with English abstract) [] Jain AK, Prabhakar S, Hong L A mlti-channel approach to fingerprint classification In: Proceedings of the Indian Conference on Compter Vision, Graphics, and Images Processing (ICVGIP 98) New Delhi, 998 53~58 http://biometricscsemsed/ pblicationshtml#finger [3] Kawagoe M, Tojo A Fingerprint pattern classification Pattern Recognition, 984,7(3):95~303 [4] Maio D, Maltoni D A strctral approach to fingerprint classification In: Proceedings of the 3th International Conference on Pattern Recognition (ICPR) Vienna, 996 578~585 http://biascsrniboit/maio/ [5] Kar K, Jain AK Fingerprint classification Pattern Recognition, 996,9(3):389~404 [6] Jain AK, Prabhakar S, Pankanti S Mathing and classification: A case stdy in fingerprint domain Proceedings of the INSA-A (Indian National Science Academy), 00,67():67~85 [7] Lmini A, Maio D, Maltoni D Continos vs exclsive classification for fingerprint retrieval Pattern Recognition Letters, 997,8(0):07~034 [8] Cheng JG, Tian J, Ren Q, Zhang TH Singlar point-based fingerprint classification In: Proceedings of the nd Workshop on Biometrics in Conjnction with the 6th International Conference for Yong Compter Scientists Hangzho: 00 S4-7~S4-34 (in Chinese with English abstract) [9] Srinivasan VS, Mrthy NN Detection of singlar points in fingerprint images Pattern Recognition, 99,5():39~53 [0] Bazen AM, Gerez SH Extraction of singlar points from directional fields of fingerprints In: Annal CTIT Workshop Enschede, 00 http://telnteltwentenl/cgi-bin/sabih/ctit0pdf?sendfile=ctit0pdf [] Zhang WW, Wang S, Wang YS Corner detection based singlarity detection of fingerprint image In: Proceedings of the nd Workshop on Biometrics in Conjnction with the 6th International Conference for Yong Compter Scientists Hangzho: 00 S4-5~S4-56 (in Chinese with English abstract) [] Ratha N, Kar K, Chen S Jain AK A real-time matching system for large fingerprint database IEEE Transactions on Pattern Analysis and Machine Intelligence, 996,8(8):799~83 [3] Jain AK, Hong L, Bolle R On-Line fingerprint verification IEEE Transactions on Pattern Analysis and Machine Intelligence, 997,9(4):30~34 : [],, ( ),00,38():9~35 [8],,, : 6 :00S4-7~S4-34 [],, : 6 :00S4-5~S4-56