do<).nth~ng nay voi duong th~ng 0= 0 (trang kh6ng gian tham 56) Ia do<).n th~ng co cac di€m dfiu Ia (p = X,'arl,0= 0) va (p = Xend,0= 0).
T~p hQp giao diem cila cac duong hlnh sin tuong ling voi cac diem thuQc
do<).nthhg nay voi duong th~ng 0= nl2 (trong kh6ng gian tham 56) la
do<).nth~ng co cac diem dfiu la(p= YSlar"0= n/2) va (P= Yend,0= nl2).
.
4.11.3. Cijp nhijt khOng gia1ldnh vel khOng gia1l tham sff
Voi m6i do<).nth~ng vua xac dinh duQc, 10<).ibo tilt ca cac di6m thuQc do<).nth~ng d6 ra khoi kh6ng gian anh (dn dlfa vao dO day cila do:)n thang d6 lo<).ibo het nhung diem thuQCoo<).nth~ng, o~c bil$t trang trl1ong hop oo<).nth~ng c6 dQ day [un). Tuc1ng ling vdi vii;c Jo<.lib() cac diem nay, kh6ng gian tham s6 cling dn duQc c~p nh~t l<).i.Sau khi thlfc hil$n xong giai oo<).nnay, ta quay l:)i buoc 2.aM
tiep t\lc xli' 1,9cac peak con l<).itrong kh6ng gian tham so.
Ket lu4n
Vdi ml.)c lieu d~t fa, lu~n an dii dat duQc mot 56 ket qua Cl.)th€ sau:
. Giai quyet bai loan vector boa ban d6 theo hai huang tier e~n. Huang tier c~n ilia nhilt dung cae thu~t loan xu Iy anh truy€n th6ng thong qua de bude ti~n xu Iy, lam manh duong bien, ... u€ Jin JuQt vector boa loan anh. Phuong phap nay co u'u di€m Ja co t6c do xu Jy eao. Dong gap ehinh eila lac gia trang phu(Jng phap nay Ja c1iiciij lien va t~n dl.)ng t6t mot s6 thu~t loan lien xu Jy anh d€ nang cao chill JuQng va t6e do xU'Iy. Nho k0t hQp vdi each t6 chUc lliu trITdcr Ji~u hQp Iy, anh vector nh~n duQc co kern theo cae thong tin topology b6 trQ rilt hieu qua cho qua trlnh HI dong xac
djnhcae U6ittf<,1ngd"ng vilng va b6 sung hoan ehinh quan h.; tapa giUa cae U6i tu'Qngtren anh sau mly. Phu'dng phap thu hai dlfa tren cae phep bic'n d6i Radon vit Hough de vector boa anh ma khOng dn thOng qua bu'oe Jam manh du'ong bien (thinning) lit bu'oe xU'Iy anh thu'ong lam milt mat thong tin diln Mn sai s6 trong phu'dng phap d~u. Dily la mOt phu'dng phap moi. Phu'dng phap nay lam vi.;e t6t ngay khi anh bitmap d~u vao khong co chill Iu'Qngt6t. Day Ja mOt u'u diem quan trQng. D~e bic$t,tole gia dii giai quye't t6t cae viln d~ lien quan Mn anh kich thu'oe Ion (nhu' cae ban d6) va t6e dO cling nhu' dO ehinh xae eila phep bie'n d6i Radon (va Hough) khi Xl(Iy anh IOn.
. Trang khi nghien euu ling d\lng phep bie'n d6i Radon va Hough, tole gia dii co nhung nghien euu danh gia nghiem tue v~ slf ;loh hu'dng eila t~n suilt lily milu khi roi r"e hmi khOng gian tham s6. Dlfa vao nhung ke't qua danh gia nay, ta co the ehQn Ilfa cae tham s6 t6t trong qua tdnh tinh loan bie'n d6i Radon (hay Hough).
. De tang hic$uqua xU'Iy va t~n d\lng tai nguyen trong moi Wong h"n ehe', tole gia dii xay dlfng mOt s6 thu~t loan song song eho phep bie'n d6i Radon cling nhu' Hough (cae thu~t loan DRT, DTRT, ATRT va MATRT). Nhung thu~t loan nay lam vic$e tren cae may tjnh song song co bO nho philn b6, phil hQp vdi cae moi tru'()ng may tinh song song re ti"';n. Ngoai ra, tole gia dii ling d\lng logic mo de tang dO ehinh xae khi xae d!nh cae peak trong khong gian tham s6.
Tole gia cling dii d"'; nghi mOt s6 thu~t loan hi.;u qua eho phcp xae djnh cae U6i tu'<:;fngd"ng du'ong Iron va ellipse (thu~t loan tlfa Hough, thu~t loan diem d6i xung, ...). Nho vic$etach bai loan xae djnh du'ong Iron (hay ellipse) thanh hai bu'oe (xae djnh tam va xae djnh cae tham s6 con I"i), cae thu~t loan do tolegia d~ nghj co hi.;u qua eao.
v~ m~t lu'u tm, tole gia dii du'a ra cae philo tieh va gi<Jithi.;u mo hlnh lu'u tru du Ii.;u anh vector kern thong tin top a VOl3 mue dO topo khae nhau dlfa tren ehu5n VPF. Vic$enghien euu du'a ra mOt djnh d"ng lu'u tm dfi'li.;u GIS la dn thie't VIm6i qu6e gia Mu dn djnh d"ng eila rieng mlnh de baa dam tinh baa m~t va an loan du lie;u, di~u rat kh6 !lito dam khi sti d\lng cae dinh d,~ng eua nu'oe ngoai. Tuy vaY, dG d,lm bao kha nang hOi nhaP, thiet kc' diJ'lic:;utheo ehu5n lit h~1pIy.
MOt ke't qua dang ehuykhae eua lu~n an la eai tie'n thu~t loan tlm giao eua hai da giae bilt ky. Day Ja mOt bai loan cd Sd va co rilt nhi~u ung d\lng trong cae hc$th6ng GIS (tinh loan md du'ong, phung duong, giai phung m~t biing, ...). Phudng an do lac gia d~ nghj eho phep nang eao dang ke hic$u qua eua thu~t loan Weiler-Atherton nho vic$e e\le bO boa cae tinh loan giao diem gitia hai da giae dlfa tren duong sweepline. Thu~t loan nay d~e bic$t hie;u qua d6i VOlcae dti li.;u khOng gian trong cae he; thGng GIS khi cae da giac co s6lU<:;fngdinh rilt IOn (hang tra~ ngan dlnh) va hlnh dang phue t"p (co the co 16 nhi"';u t~ng).
Cae ke't qua eila lu~n an dii duQe tole gia dang trong 14 eong tdnh , trong do co 9 eong tdnh dang tren cae t"p chi, hOi nghi qu6e te'va 5 eOng tdnh dang trang nudc.
r :---"\ \ 1.11./ !I, '! 1\I , ll I':.: '1" I ,.J' L' . ",' -' 1 ,. ,,'. ,,;" ~ I
DANH SACH cAc BA.I BAD LIEN QUAN DEN LUJ-N AN
1. Duong Anh Duc, "An Algorithm for Map Vectorization", Proceedings of
International Conference on Image and Signal Processing ICISP'2001; 03-05
May 200l, pp 80-89.
2. Duong Anh Duc, "Parallel Algorithms for Hough and Radon Transforms", Ky
yeu H('Jithilo QurJcgia v~ Olng ngh~ ThrJng tin, Hue' 09-1110612000, NXB
KHKT 2001, tr. 54-62.
3. DudngAnh Duc, LC Thl,lYAnh, Dinh Ba Tie'n, "MOt s6 ung dl,lng cua 19
thuye't d6 thi trong vii;c xiiy d\l'ng hi; th6ng hudng dan giao thong", Ky y(u
H(Jinghi Ung dlmg ToGn hpc toan quf/c Ian till) n/utt, Hil NOi, 23-25/12/1999,
tr.183-190.
4. Duong Anh Duc, Lc mnh Duy, "NghiCn cuu mOt s6 each ti6p c~n xiiy dl,fng (adsbygoogle = window.adsbygoogle || []).push({});
hi; thong WebGIS", Ky yeu Hr)i nghi khoa hQc Tru(lng DH KHTN, DHQG Tp.
HCM 512000, tr. 135-140. .
5. Duong Anh Duc, Nguyen Dong Ha and Le thi Thuy Hang, "Building a
topological map edit tool with the support of CGAL", CGAL User Workshop,
Spain, June 2002.
6. Duong Anh Duc, Nguyen Dong Ha and Le thi Thuy Hang, "A Solution for
Topological Map Edit-tool Developing ", Proceedings (~/'Inter. C0I1/'erenceon
Computer Science, Software Engineering, Information Technology, e-Business, and Applications (CSITeA'02) Brazil, June 2002.
7. Duong Anh Duc, Bui Doan Khanh, "An Application of Radon Transform for Automatic Map Vectorization", Ky y€u HOi ngh! IT@EDU2000, tr.56-66. 8. Duong Anh Duc, Bui Doan Khanh, Vu Thanh Nguyen, "A Fuzzy Hough
Transform Approach For Line Detecting ", Journal of lmtitute of Mathematic.r
and Computer Sciences, India, Vol. 12, No.2, Dec 2001, tr. 193-200.
9. Duong Anh Duc, Bui Doan Khanh, Vu Thanh Nguyen, "A Fuzzy Hough Transform Algorithm for Line Detection", Pro~dings of Image and Vision Computing IVCNZOl, New Zealand 2001, pp. 249"252.
10.Duong Anh Duc, Dao Minh Son, "A Fast Elliptic Object Detection
Algorithm", Proceedings of Image and Vi.fion Computing NCNZOI, New
11.Du'ong Anh Duc, Nguyl!n Hdng Son, "The Hough Transform for edge
detecting", Ky yiu Hl)i tllao Qu6c gia v4 Tin IIQc ling (It,mg, Qui Nhon 8/1998,
If. 58-66
12.Duong Anh Duc, Tran Minh Triet, "The fast fuzzy hough transform algorithm for elliptic object detection", Proceedings of the International Conf. on Computational Mathematics and Modeling (CMM2002J, EAST-WEST Journal of Mathematics, Thailand, May 2002, pp.48-54.
13.Hoang Van Kiem, Duong Anh Due, "Applying Algebraic Curves In Digital
Image Vectorization", Journal of Institute of Mathematics and Computer
Sciences, India, Vol. 13, No. 1,2002, pp. 5-24.
14.Hoang Van Kiem, Duong Anh Due, Le Dinh Duy "A Fast Algorithm for
Polygon Clipping", Journal of Institute of Mathematics and Computer