^^f /Ho 5"

TRlTOfNG DAI HOC AN GIANG
KHOA KY THUAT - CONG NGHE - MOI TRU^NG

NGUYEN TAN AN - DTH092021

KHOA LUAN TOT NGHIEP D^I HOC NGANH C^ NHAN TIN HOC

TIM HIEU KY THUAT NHAN DANG KY
TU SO VIET TAY VA ifNG DUNG NHAP
DIEM TU DONG
•••

TR^CiNG DAI HOC
AN GIANG

THUVIEN

Giang vien huong dan
TS.NguyinVanHoa

An Giang, 05/2013


LOI CAM ON
Dlu tien em xin giii lbi cam cm din cac thiy co da tSn tinh giang day truyln dat kiln
thiic cho em bao nam qua hoc tai truang Dai hoc An Giang noi chung va dac biet khoa
Ky thuat Cong nghe Moi tnrang noi rieng. Em xin gui loi cam on sSu sac nhSt den
thay giao, tien si Nguyen Van Hoa nguoi da tan tinh hudng dan em trong suot qua
trinh thurc hien bai bao cao nay.

Em cung xm bay to loi cam cm sau sic din thly Huynh Ly Thanh Nhan nguoi da tao
nen tang lap trinh cho em va anh Nguyen Duy Dat nguoi da tan tinh goi y giiip d& em
trong qua trinh nghien ctru thurc hien bai bao cao. Dong thai, em cung xin guri lcri cam

an din hai thiy la thly Huynh Cao Thl Cuang va thiy Le Van Toan da gai f giup d&
em hoan thanh bai bao cao tot han.
Cuoi cung, em muon guri lcri cam an chan thanh den tat ca bah be, va dac biet la ba, me

va ban Ngo Do Bao Uyen, nhung ngubi luon kip thai dong vien va giup d& em trong
suot qua trinh thurc hien.
Em xin chan thanh cam an.

Tp LongXuyen, ngay 18 thdng 5 nam 2013
Sinh vien

Nguyin Tin An


TOM TAT
Nhan dang ky tu dac biet la ki tu viet tay v&n chua co dupe mot giai phap tong the, cac
ling dungcua no cung chi gioi han trong pham vi hep, bai toan nay chua the giai quyet
trpn ven vi no phu thupc nhilu vao ngubi vilt va su biln d6i qua da dang trong each
viet cua tirng ngubi.

Cac phuong phap tiep can de giai quyet bai toan nhan dang ky tu viet tay kha phong
phu, mot so phuong phap duqc ap dung nhu: mo hinh Markov an, mang no-ron nhan

tao hay phuong phap may hoc vec-to h6 trg (S VM),....
Trong bao cao nay, chung toi se trinh bay t6ng quan til viec thu thap dft lieu din mot
s6 ky thuat xu ly anh ky tu d^u vao va xay dung bo phan ldp tren phuong phap may

hoc vec-to h trp va mang no-ron nhan tao dl giai quyet bai toan nhan dpg ky tu, tuy
nhien do su phirc tap cua viec nhan dang tap ky tu viSt tay va giai han vS ki^n thiic va
thai gian nen a bao cao nay chiing t6i chi tien hanh xii ly nhan dang tren tap ky tu so
viet tay. Phan thii hai ciia bao cao thuc hien xay dung ling dung nhap diem tu dpng
dua tren ky thuat nhan dang ky tu so viet tay da tim hieu va k^ thuat tach anh van ban.
Ve ky thuat nhan dang ky tu so viet tay, bao cao chia lam 3 giai doan chinh:
-Giai doan thu thap va ti^n xii ly du lieu g6m cac qua trinh thu thap d^ lieu, tach
anh ky tu tir anh dau vao, xur ly ^nh, chuin hoa anh.
-Giai doan hu^n luyen dflr lieu g6m qua trinh trich chpn dac trung, xay dung cac
bo phan lop voi phuong phap SVM va phuong phap mang no-ron nhan tao.
-Giai doan phan lop danh gia thu nghiem vbi mo hinh phan loai da x^y dung.
Ve ling dung nhap di&n tu dpng, bao cao trinh bay cac van de:
-Phuong phap tach cdc thanh phan tir anh bang diem gom cac qua trinh tach khoi
bang diSm, tach cot, hang bang dilm, tach cum ky tu, tach ky to in va tach ky tu
so viet tay, cac qua trinh tach nay dupe xay dpng tren cac phuong phap xii ly
anh.

-Ung dung SVM va mang no-ron nhan tao vao nh^n dang ky tu in va ky tu so
viSt tay trong bang di&n: TiSn hanh xay dpng cac bp phan lop cho tapky tu in
va ky tu so viet tay, kiem tra va danh gia ket qua nhan dang.
Ve phan danh gia ket qua thuc nghiem, chiing t6i da thu thap 11400 ky tp so viet tay
d lam tap hoc va tap ki^m tra cho ph^n kim tra k^t qua ky thuat nhan dang ky tu so
viet tay va 15 bang dilm mlu dl lam kilm tra cho ling dung nhap diem tu dpng.


MUCLUC
CHUtSNGLTONGQUAN1
l.l.Ly dochond^tai'1
1.2.B6i tugng va pham vi he thong1
1.3.Muctieu2


CHITONG 2: CO SCS LY THUYET3
2.1.Khainiemvganhs63
2.2.Phucmg phap tim nguong Otsu cho nhi phan hoa anh4
2.3.Thanh phfin lien thong trong anh nhi phan5
2.4.Phep toan hinh thai hoc (Morphology)6
2.4.1.Phan tu cau tnic (structing element)7
2.4.2.Phep gian nhi phan (Dilation)7
2.4.3.Phep co nhi phan (Erotion)8
2.4.4.Phep m^ anh (Opening)9
2.4.5.Phep dong anh (Closing)9
2.4.6.Tim khung xvrong (Skeletonization)10
2.5.Lpcanh11
2.5.1.Lpctrung vi11

2.5.2.KM thanh phdn lien thong ldm va nho12
2.6.Luge d6 chiSu (Histogram)12
2.6.1.Luge d6 miic xam12

2.6.2.Luge d6 chieu ngang va luge d6 chiSu doc13
2.7.Giai thuat to mau theo dong quet cai ti^n13
2.8.Ap dung phuong phap Hough tim goc nghieng cua anh14
2.9.ChuSn hoa kich thudc16

CHHONG 3: PHAN LCJP VCil SVM VAMANGNO-RONNHANTAO17
3.1.Giai thieubai toan phan ldrp17
3.2.Phan lop voi SVM17
3.2.1.Trich chon dac trung waveletHaar17

3.2.2.May hoc vector hfitrg SVM19

3.2.3.SVM.Net25
3.3.Phan lop voi mang no-ron nhan tao26
3.3.1.Mang na-ron nhan tao26

3.3.2.Thu vien FANN (Fast Artificial Neural Network)34

CHHONG 4: NIDI DUNG THUC HIEN VA KET QUA NHAN DANG KY TH SO
VIETTAY36


4.1.Mo hinh bai toan36
4.2.Qua trinh ti&i xii ly37
4.2.1.Lpctrungvi (Median Filter)37
4.2.2.Xam hoa anh (GrayScale Image)38
4.2.3.Nhi phan hoa (Binary Image)38
4.2.4.Phep toan hinh thai (Morphology)39
4.2.5.Tim gioi han cac ky tu (Get boundary box)39
4.2.6.Gpp cac thanh ph^n lien thong gta (Merge connections)41
4.2.7.Loc thanh phiin lien thong lorn va nho (Filter connections)44
4.2.8.Tach va chu&i hoa kich thuoc anh (Drop and resize)46
4.2.9.Lay xuong cua anh (Skeletonilation)46
4.3.Thu thap tap dft lieu46
4.4.Xay dung bp phan lop SVM49
4.4.1.Trich chpn dac trung49
4.4.2.Chien lupc xay dung bp phan lop49
4.5.Xay dung bp phan lop bang mang No-ron MLP49
4.6.KSt qua thu nghiem50

CHl/ONG 5: LlNG DUNG NHAP DIEM TU DONG54
5.1.M6tabaitoan'.54


5.2.Co so ly thuy^t xii ly bang di^m55
5.2.1.Mo ta bang di6m55
5.2.2.Mo hinh bai toan57
5.3.Cai dat chuong trinh59
5.3.1.Qua trinh chinh nghieng anh bang diem59
5.3.2.Qua trinh tach khoi bang diem60
5.3.3.Qua trinh tach thong tin va trang cua bang diem67
5.3.4.Qua trinh xay dung bp phan lop69
5.4.K6t qua xu ly nhap diSm tvr dpng69

CHUONG 6: KET LUAN VA HU6NG PHAT TRIEN75
6.1.Kit qua dat dupe:75
6.2.Huong phat trien75


DANH SACH HEVH VE
Hinh2-1: Anhnhiphan; (A) anh dau vao, (B) anhnhiphan3
Hinh 2-2: Phucmg phap nhi phan anh; (A) Histogram cua anh da capxam nguyen
ban,(B) ngu&ng thip, (C) nguomg thich hop, (D) nguang cao.[22]4
Hinh 2-3: Thanh phan lien thong vdi 4 va 8 ketnoi6
Hinh 2-4: Thanh phdn lien thong trong anh6
Hinh 2-5: Cac loai pMn tu cu true7
Hinh 2-6: Phep gian nhi phan [8]8
Hinh 2-7: Phep co nhi phan. [8]8
Hinh 2-8: Phep md anh nhi phan. [8]9
Hinh 2-9: Phep dong anh nhi phan. [8]10
Hinh 2-10: Qua trinh tim khung xurong cua anh. [8]11
Hinh 2-1 l:Lpc trung vi12
Hinh 2-12: NhiludOmvanhiSu vet dai. [12]12

Hinh 2-13: LupcdOmucxam13
Hinh 2-14: Lucre d6 chiSungang13
Hinh 2-15: Lucre do chieudpc13
Hinh 2-16: TO mau theo duomgbien.[19]14
Hinh 2-17: Hai each tO mau dung 4 lien thOng va 8 lien thOng14
Hinh 2-18: Phucmg trinh duomg thing tren he tpa dp Decard.[19]15
Hinh 2-19: Phuomg trinh duong thing Hough.[19]16
Hinh 3-1: Trichchpndac trung waveletHaar.[18]17
Hinh 3-2: Day dactrungwaveletHaar.fi8]18

Hinh 3-3: PhSnlopSVM.fi]19
Hinh 3-4: SiOu phang phan chia hai tap mau. [24]20
Hinh 3-5: Phan lop tuyen tinh d(J lieu khOng tach rcri.[l]21
Hinh 3-6: Phan lop phi tuyen. [1]23
Hinh 3-7: Phan lop tuyen tinh trong khong gian trung gian. [1]23
Hinh 3-8: Mang na-ron sinh hoc26
Hinh 3-9: Mang na-ron nhan tao27

Hinh 3-10: M0 hinh mang mot lop29
Hinh 3-11: Vi du ve mot mO hinh mang na-ron da tang29
Hinh 3-12: Mang na-ron perceptron30
Hinh 3-13: Mang na-ron MLP31
Hinh 3-14: Luu dO giai thuat Ian truyOn nguac huan luyen mang MLP33
Hinh 3-15: vi du dinh dang tap du lieu cua thu vien FANN35
Hinh 4-1: M0 hinh bai toan36
Hinh 4-2: Anh ky tu dau vao36
Hinh 4-3: Qua trinh tiOnxuly37

Hinh 4-4: Anh bi nhiOu dOm37



Hinh 4-5: Anh sau khi loc trung vi38
Hinh 4-6: Xdm hoa anh; (A) anh diu vao, (B) anh da ltai xam38
Hinh 4-7: Anh sau khi nhi phan38
Hinh 4-8: Phep dong anh; (A) anh sau khi nhi phan, (B) anh sau khi sur dung phep
dong anh39
Hinh 4-9: Hinh chu nhat giori han cac ky tir s639
Hinh 4-10: Liru d6 tim giai han ki tu41
Hinh 4-11: Gpp cac thanh phin lien thong; (A) thanh phSn lien thong bj tach roi cua 1
ky tu, (B) sau khi gpp cac thanh phan lien thong42
Hinh 4-12: Lira d6 giai thuat gpp cac thanh phin lien thOng g^n43
Hinh 4-13: Lira do giai thuat xac djnh hai hinh chd nhat giao nhau44
Hinh 4-14: Lira d6 giai thuat lpc thanh ph^n lien thong ldn va nho..45
Hinh 4-15: L^y xuong cua anh46
Hinh 4-16: Tap dtt lieu s6 047
Hinh 4-17: Tap da lieu s6 948
Hinh 5-1: Qua trinh cua he th6ng nhap di6m to dpng54
Hinh 5-2: Anh bang dilm56
Hinh 5-3: Mo hinh xuly57
Hinh 5-4: Mot s6 dirong thing Hough ke theo each co ban59
Hinh 5-5: Duong thing Hough ke theo phuong phap cai ti^n59
Hinh 5-6: Lupc d6 chi6u ngang cua anh bang diim; (A) Lupc d6 ban diu, (B) Lupc d6
sau khi su dung phep toan hinh thai61
Hinh 5-7: Lupc do chieu doc ciia khoi bang diem62
Hinh 5-8: Lupc d6 chiSu ngang cua khoi bang dilm63
Hinh 5-9: Anh cac ky tu MSSV bj dinh nhau64
Hinh 5-10: Cac thanh phin cin tach trong kh6i thong tin va trang cua bang diSm67
Hinh 5-11: Lupc do chieu ngang cua khoi thong tin bang diem67
Hinh 5-12: Lupc do chieu doc cua hang thong tin mon thi68



DANH SACH BANG BIEU
Bang 4-1: Bang qui ubcno-ron dauracua 10 ky tuso50

Bang 4-2: Ma tran confusion kit qua nhan dang bang SVM51
Bang 4-3: Ma tran confusion ket qua nhan dang bang mang no-ron Ian 151

Bang 4-4: Ma tran confusion kit qua nhan dang bang mang no-ron Ian 252
Bang 4-5: Ma tran confusion ket qua nhan dang bang mang no-ron ISn 352
Bang 5-1: Bang ket qua cac qua trinh tach bang diem ban dau70
Bang 5-2: Bang kit qua chi tilt phln nhan dang ky tu in trong MSSV71
Bang 5-3: Bang kit qua tach ky tu va nhan dang MSSV71
Bang 5-4: Kit qua cua qua trinh tach ky tu dilm si71
Bang 5-5: Ma tran confusion ket qua nhan dang diem so da tach va khong xoa dubng
gach 6 dilm bang svm72
Bang 5-6: Ma tran confusion kit qua nhan dang dilm si da tach va xoa dubng gach 6

dilm bang svm72
Bang 5-7: Ma tran confusion ket qua nhan dang diem so da tach va khong xoa dubng
gach 6 dilm bang mang no-ron73
Bang 5-8: Ma tran confusion ket qua nhan dang diem s6 da tach va xoa dubng gach 6
dilm bang mang na-ron73


Tim hieu ky thuat nhan dang ky tyr so viet tay va ung dung nhap diem tyr dong

CHlTONG 1: TONG QUAN
1.1.Ly do chon de tai

Nhan dang ky tir la mot linh we trong do quan tam tai kha nang cua may tinh co

thi nhan biet dirge cac ky tu. Cac ky tu nay co the dugc tao ra bang may hay dugc tao
bdi con ngudi, sau do chuyen cac tai lieu nay sang ede dang tai lieu ma may tinh co the
doc dugc nhu: scan anh, anh chup bang camera, ... . Va bai toan nhan dang ky tu hien

nay da dugc ung dung kha nhilu trong thuc tl, nhu cac he thing nhan dang cac ky tu
in cho qua trinh sao luu sach bao tai lieu, he thong nhan dang ma vach, bien so xe, cac
he thong nhan dang ky tu viet tay cho cac phieu dieu tra tu dong, cac bieu mau,... Cac

he thong nhan dang nay se tiet kiem dugc nhieu chi phi ve thai gian, cong sue.
Nhan dang ky tu thuong co hai dang la nhan dang ky tu in va nhan dang ky tu
viet tay. Hien nay thi bai toan nhan dang ky tu in da dugc giai quyet gan nhu trpn ven,
tuy nhien vdi bai toan nhan dang ky tu viet tay vln con la thach thuc Ion do co nhieu
khd khan nhu khong co khai niem font chu chung, kich thudc chu, dp rpng hep, cao
thip cung khac nhau, dp nghieng do each viSt cua mi ngucri khac nhau, ..., ved nhung
ygu t6 nhu vay se lam cho s6 mlu d^u vao ion, va gitta nhi8u mlu dau vao cua cung
mot ky tu co su khac biet Ion din din kit qua nhan dang kern hieu qua.
Tir truac din nay, a nude ta cung cd nhilu cong trinh nghien cuu ve lihh vuc bai
toan nhan dang ky tu, va phuong phap may hoc pho bien nhat trong nhan dang ky tu
thudng dugc ung dung la mang na-ron nhan tao (Artifical Neural Network) va ti le
thanh cong cua phuong phap nay d nhilu cong trinh cung dat dugc khd cao nhu he
nhan dang chu in dua tren mo hinh mang neuron bon ldp cua hai tac gia Wang va Jean
trong [1] cd ty le nhan dang chinh xac tdi 99,81%. V^ nhung nam gan day mot phuong
phap khac trong linh vuc khai khoang du lieu thudng dugc ap dung cho bai toan nay la
phuong phap may hoc vector h trp, day la mot giai thuat tien tien cd dp chinh xac
cao.

Tuy nhien dl phuong phap cho ra cac kit qua cao thi qua trinh phan tich xu ly
dau vao cung rat quan trong, qua trinh xu ly tot se giup cho tap du lieu mau cho qua
trinh phan ldp, cac tap du lieu nay se tit hen, tur do giup viec nhan dang se dat dp
chinh xac cao hon.


Tren ca sd tren, nhan thay su phuc tap cua bai toan nhan dang ky tu viet tay va
thdi gian thuc hien cung nhu viec thu thap tap d^ lieu mau con nhieu han che va cho
thfiy su tog dung cua bai toan trong thuc te nen chung toi chpn de tai:
"Tim hiiu ky thuat nhan dang ky tir si viit tay va vng dung nhap diem tir
dong".

1.2.Doi tirong va pham vi he thong
D8 tai nay chu ylu tap trung vao nhan dang ky tu si viit tay, bp du lieu mlu se
dugc tir thu thap, sau do tim hiiu ky thuat xu ly phan tich anh dlu vao va sir dung bp
may phan ldp may hoc vector ho trp va mang na-ron nhan tao cho vifc nhan dang. Tir
do lam ca sd xay dung ling dung md rpng cho viec nh^i dang ky to in va ky tu si viet
tay trong phln ung dung nhan dang dilm tu phieu dilm, ben canh nhan dang, trong
ung dung nay cung tap trung nghien cuu vao qua trinh xu ly tach anh van ban.

SVTH: Nguyen TSn An - DTH092021


Tim hieu ky thuat nhan dang ky tu so viet tay va ling dung nhap diem tir dong

1.3. Muc tieu

-Tim higu cac ky thuat d giai doan tien xu ly;
-Hieu may hoc vector ho tra, mang no-ron nhan tao va umg dung vao nhan dang

ky tir so viet tay;
-Tim hieu mot so phtrong phap trong llnh vurc xtr ly anh de (ing dung tach van
ban cho bang di^m va tach cac ky tu so viet tay;
-Tim hieu va sir dung ma nguon md SVM.net va FANN ho tra cho viec xay
dung ung dung.


SVTH: Nguygn TSn An - DTH092021


Tim hieu ky thuat nhan dang ky tu so viet tay va ung dung nhap diem tir dpng

CHI/ONG 2: CO S6 LY THUYET
2.1. Khai niem vi anh so

Anh so la hinh anh dugc luu trong cac thiet bi so nhu may anh ky thuat so, may
tinh hoac cac thilt bi so khac. Anh s6 la mot mang hai chilu g6m cac dilm anh (pixel),
moi diem anh dugc xac dinh bbi tga do (x,y) va dugc bieu dien bbi n bytes dubi cac he
mau khac nhau, theo he mau thubng co 3 loai anh chinh:
-Anh mau (color image): moi diem anh co gia tri gom 3 mau do (red) cong xanh
luc (green) cong xanh duong (blue). Moi mau co gia tri tir 0 den 255, nghia la
moi diem anh can 24bits hay 3bytes de bi^u dien.
-Anh xam (gray image): gia tri moi diem anh nam trong giai gia tri tir 0 den 255,
nghta la cfin 8 bits hay 1 byte di bilu diln m5i di^m anh nay.
-Anh nhi phan (binary image): gia tri mi dilm anh la 0 hoac 1, nghia la tr^ng
hoac den. Khi xh ly tren may tinh thi ngubi ta dung anh xam d^ bi^u diln anh
nhi phan va luc nay 2 gia tri la 0 hoac 255, gia tri 0 bi^u diln cho mau den va
gia tri 255 bilu diin cho mau tr5ng (Hmh 2-1).

^ OX X1 l-i i OOOoo a^ XI1

(A)

CB)

Hinh 2-1: Anh nhi phan; (A) anh dan van. (I!) anh nhi phan.


Trong thuc te, anh nhan vao ban dau thubng la anh mau RBG, vi vay de thuc
hien qua trinh phan tich va nhan dang chung ta can phai chuyen chung thanh anh nhi
phan. Be chuyen tb anh mau sang anh nhi phan, chung ta can chuyen anh mau thanh
anh xam trubc, sau do so sanh muc xam cua tirng diem anh vbi mot nguong

(threshold) thich hgp (Hinh 2-2) de quyet dinh diem do se la 0 hay 1. Be chuyen doi tu
anh mau RBG sang anh xam 8bits thubng sir dung mot trong 2 cong thuc sau, ap dung
cho tirng diem anh (x,y):
lxy = 0,3086 * Redxy + 0,6094 * Greenxy + 0,0820 * Bluex>y
Ixy = 0,299 * Redxy + 0,587 * Greenxy + 0,114 * Bluexy

SVTH: Nguyen Tan An - BTH092021


Tim hieu ky thuat nhan dang ky tu so viet tay va img dung nhap diem tu dpng

o
(trar^
b) ngi^pg tba

pJchonngiSng
thfchhop

Topping the
Tqtant of Russia's
SdenKsts, p.5

Iiiuh 2-2: Phtrong phap nhj pkan ,'iiih: (A) Histogram cua anh da cap jam ngiiyen ban,(B)
nguong (hap, (C) nguong thich hop, (D) ngirong cao.|22]


Thudng co 2 c^ch ldy nguong, liy nguong c6 dinh va ldy nguong tir dong,
nguong co dinh thudng dupe sir dung trong cac ung dung vai cac doi tupng co dinh,
cac doi tupng co mat dp xam giong nhau, qua thuc nghiem xac dinh dupe mot nguong
toi uu giup viec phan tach cac doi tupng t6t nhat (tach phan anh va phan nen ro ret).
Con ve nguong khong c6 dinh, gia tri cua nguong se thay d6i tuy theo su bien thien
ciia tap du lieu theo khong gian va thai gian, thong thuong dupe xac dinh thong qua
viec kh^o sat tap du lieu bSng cac phuong phap thbng ke. Trong npi dung luan van nay
chung toi su dung phuang phap Otsu d6 tim nguong t6i uu cho viec nhi phan anh diu
vao.

2.2. Phirong phap tim nguong Otsu cho nhi phan hoa anh
Phuang phap Otsu la phuang phap tim nguong toi uu cho viec nhi phan anh dpa
vao lupc do xam cua ^nh. Thuat toan gia dinh ring anh se g6m 2 thanh phan la phln
anh va phan nen, vi vay nguong t6i uu la ngu&ng co thl phan tach 2 thanh nay mot
each ro nhat va lam giam thi^u s6 chi tiSt d6i tupng anh bi mit.

SVTH: Nguyln Tin An - DTH092021


Tim hieu ky thuat nhan dang ky tu so viet tay va ling dung nhap diem tu dpng

Trong phucrng phap nay, dau tien ta phai chuyen anh dau vao thanh anh xam, sau

do lay lupc do xam cua anh nay. Co tong cpng 256 gia tri de bieu hien muc xam, theo
Otsu, moi miic xam se tinh ra mot gia tri al , va nguong toi uu la nguong tai miic xam

co gia tri al cue dai. Gia tri al dupe tinh nhu sau:
al — a.x{Tm.x — ml)2 + a2(m2 — mt)2


Tai gia tri muc xam t se chia lupc do xam thanh 2 phin Cx va C2 , Cx la phin lupc
d6 co gia tri nho hon hoac bang t (tir 1 den t) va C2 la phan lupc do co gia tri Ion hon t

(tir t din 254).
Trong do:
pt la xac suat cua mot miic xam i
a;- la tong xac suat tren doan j
^ Pi ,

7 = 1,2

rrij la gia tri muc xam trung binh tren doan j

Zi.pi,

7 = I,2

a.j

Dl dang nh^n thiy:
mc = mxax + m2a2
ax + a2 = 1

Ta dupe bieu there tinh al don gian hon:
ab = axa2(mx — m^)2

Tir do ngu&ng k* t6t nhit se dupe xac dinh bing each tim ra gia tri al Ian nhit.
k* =Max{aB2(t)} , 1 < t < 255
2.3. Thanh phan lien thong trong anh nhi phan
Nhu da trinh bay if phan tren anh nhi phan la anh ma tai moi diem anh co 2 gia tri

la 0 hoac 1, trong do nhung diem anh co gia tri 0 dupe xem la nen va nhung diem anh
co gia tri 1 dupe xem la nhiing thanh phan trong anh. Tir nhung diSm anh co gia tri 1,
ngucri ta dinh nghia ra mot s6 nguyen tic di xac dinh thanh phin trong anh co lien
th6ng vai nhau hay khong. Nhung diem anh co li&i thong voi nhau dupe gom lai gpi
la thanh phan lien thong trong anh. Tat nhien trong anh se co khong (toan la anh nen)
hoac nhieu thanh phan lien thong trong anh. Va moi thanh phan lien thong trong anh
phai co it nhat mot diem anh hoac nhieu diem anh. Thong thucmg trong ky thuat

thuong su dung 4 kit n6i hoac 8 kit nii (Hinh 2-3) di xac dinh thanh phin liSn thong
trong anh. Tuy nhien trong nhung truong hop dac biet thi so lupng n6i ket co thi khac
4 hoac 8.

SVTH: Nguyln Tin An - DTH092021


Tim hieu ky thuat nhan dang ky tu so viet tay va ung dung nhap diem tu dpng

(a) 4 n& kit

(b) 8 n6i kit

Hinh 2-3: Thanh phan lien thong voi 4 va 8 kit not.

Cach xac dinh thanh phan lien thong trong anh, ta di chuySn mat na quet qua
tung diem anh, diem tai trung tam (tam goi la C) dupe gan la 1 khi tai diem anh do co
gia tri 1 va co it nhat 1 Ian can trong so cac Ian can cua no (tam gpi la P) co gia tri 1
(nhttng Ian can dupe to xam) thl C dupe xem hi lien thong vai P. Hay noi khac hon C
va P cung la thanh ph^n lien thdng.

Nh5ng 6 man x^m ttrpng

trung cho diim anh co gia
Pj 1, nhung 6 mau trfing
tupng trung cho diem anh
c6 gid tri 0 (nfin)
Hinh 2-4: Thanh phan lien thong trong anh.

Nhu hinh 2-4 ta thay nSu sii dpng 4 n6i ket se xac dinh dupe 3 thanh phan lien
thong trong anh. Va n^u sit dung 8 noi ket se co 2 thanh phan lien thong trong anh.

Nhu diSm anh tai (2,2) (dong 2, cot 2) sg lien thong vai (1,2) a ch6 dp 4 n6i kSt
va 8 n6i k6t. Tuy nhien di6m anh tai (2,2) va (3,3) se khdng lien thong nhau khi a chg

dp 4 n6i k^t, nhung cr chl dp 8 n6i kit thi (2,2) va (3,3) lai lien thong vdi nhau.
2.4. Phep toan hinh thai hoc (Morphology)
Hinh thai la thu^t ngit chi su nghien cuu vl ciu tnic hay hinh hoc topo cua dli
tupng Pong anh. Nhiing dli tupng Pong hinh thai hoc ta co thl coi nhu la tap hop cua
cac diem anh, nhom lai theo ciu true ma Pan 2 chilu. Nhung thao tac toan hoc rai rac
Pen tap hop diem do dupe su dung dl lam ro nhung net dac trung rieng cua hinh dang
d6i tupng, do v^y co thl tinh toan hay dupe nhan bilt dupe chiing mot each dl dang.
Phan Ion cac phep toan hinh thai hoc dupe dinh nghla tu hai phep toan ca ban la phep
co nhi phan (Erosion) va phep toan gian nhi phan (Dilation).

SVTH: Nguyln Tin An - DTH092021


Tim hieu ky thuat nhan dang ky tu so viet tay va ling dung nliap diem tu dong

Trong npi dung luan van nay, sir dung chii yeu la 4 phep toan hinh thai: phep co
nhi phan (Erosion), phep gian nhi phan (Dilation), phep dong (Closing) va phep me
(Opening).

Trong cac phep toan hinh thai, chu y^u xet dSn 2 doi tupng la pMn tu cdu true
(structing element) va tap hop cac pMn tu cua hinh anh goc. Ta xem tap hop B la mot
phan tu cau true va tap hop A la tap hop cac phan tu ciia hinh anh goc.
2.4.1. Phan hi cau true (structing element)

Cac phan hi cau tnic thuong dupe quy dinh theo mot mau rieng dua tren tpa dp
ciia mot so diem lien quan ten doi tupng nao do. Dudi day la mot vai mau dac trung
cho cac phan tu cau tnic co kich thudc khac nhau:

Hinh 2-5: Cac loai phan tir can tnic.

Trong hinh 2-5 vong tron mau den danh dau tam cua phan tir cau tnic, cac 6 mau
xam dupe xem la cac di&n anh ciia ph^n hi cSu tnic, cac 6 mau trang xem la nen co
thfi xem chiing khong phu thupc vao ph^n tir ciu tnic.Khi mot phep toan hinh thai
dupe thuc hien thi tam cua ph^n hi cSu tnic thudng dich chuyln Ian lupt tren cac dilm
anh. Va khi do cac gia tri diem anh vita dupe quet qua se dupe so sanh vdi nhau, cac
ket qua thu dupe sau khi so sanh phu thupc vao phep toan hinh thai dang dupe sir
dung.

2.4.2. Phep gian nhi phan (Dilation)
Phep gian nhi phan ciia mot tap hop A bdi mot phan hi cau tnic B dupe ky hieu
la A © B va dupe dinh nghia qua cong thiic sau:

Nhu vay phep gian nhi phan ciia trip hop A boi phan tix cau tnic B la tap hop cua
tit ca cac dilm z (z la tam dilm cua phin hi c^u tnic B tren tap hop A) sao cho phan
xa cua Bz giao vdi tap A tai it nhdt mot di6m. Hay noi each khac, phep gian nhi phan
la su chdng cheo it nhdt mot phSn hi ttr phan xa ciia phan hi ciu tnic B vdi tap hop A.
Dong thai cac phan hi nay phai la tap con cua tap hop A.
Cach tinh Dilation cua mot anh ta tien hanh dat phan hi cau tnic B tai moi diem
anh trong anh nguon. Neu ton tai mot diem anh cua ddi tuqng nam trong B thi gan gia


SVTH: Nguyen Tan An - DTH092021


Tim hieu ky thuat nhan dang ky tu so viet tay va ung dung nhap diem tu dong

tri tai trung tarn ciia B trong anh ket qua la gia tri cua doi tuqng, ngugrc lai gan gia tri
cua nSn.
0 C 0 G 0 0.0 0 0 C 0 0 C 0. 0 0

OGOOO'OOOCCC CCOOG

o o.aKfflElc.c c^cccc^o
o ^DDK]On r, c coc"^ c,co

c cnnnnnc oo onnn c o
g onuneiho odddd o o
HU " nnDDD
0 CO C CO^ OllEinilll 09^
c co 3C09DDDDD o o c o
0 t ^ C C O[]

;i!L'iHii:i

^m
tin

llfll!l!l!

o o c cnnDEIilD o c c o o

cooooooooooc&co

Hinh 2-6: Phep gian nhj phau |8|

Tvr hinh 2-6 ta thay anh sau khi Dilation luon co xu huong md r6ng thanh phan
lien thong theo mot nguyen tac nhat dinh, nguyen tac do dua tren phan tii cau tnic B.
Vi vay tuy theo cac phan tu cau tnic khac nhau viec tinh Dilation se khac nhau.
Dilation phuc vu nhieu muc dich khac nhau nhu md rpng (phinh to) cac thanh
lien thong trong anh nhu viec noi ket cac vet dut trong ki tu lai vdi nhau, lpc bien ,...
2.4.3. Phep co nhi phan (Erotion)
Phep co nhi phan cua tap hpp A bdi phan tu cau tnic B dupe ki hieu A 0 B va
viet dudi dang cdng thiic nhu sau:

Vdi Bz = {b+z,b e B]
Nhu vay phep co nhi phan ciia tap hpp A bdi ph^n tu ciu tnic B la tap hpp cac
di^m z (z la tam diem cua phan tit cau tnic B tren tap hpp A) sao cho Bz la tap con ciia
A.

Cach tinh Erotion ciia mot anh ta tien hanh dat mat na B tai moi diem anh cua
anh nguon A. Neu tat ca cac diem anh cua doi tupng trong anh nguon nam trong B thi
diem anh tai trung diem khong thay doi gia tri, ngupc lai gia tri tai diem trung tam
dupe gan gia tri ciia nen (Hinh 2-7).

A(JLQB)
^iiainn

. sir^mn

^wsa
tin


nn

tnnn

nti^^
nn^Hn

nnnnn

B
51 SB
B
11 s If
li

nnrnnnnn
nn^rin ,

D

nrnnnnnn

nnn
nnnn

nnc^itrtnnn
. nnnnnn
Hinh 2-7: Phep co nhi phnn. |8|

SVTH: Nguyln Tdn An - DTH092021


Tim hieu ky thuat nhan dang ky ty so viet tay va ung dung nhap diem tu dong

Viec thao tac Erosion anh phuc vu nhidu muc dich khac nhau nhu bao mdn (thu
nhd) thanh ph^n lien thong, Ipc bien, co thd khu nhilu.
2.4.4. Phep md anh (Opening)
Phep md anh thudng dung dl lam tran cac dudng bien cua doi tupng anh, nhu
loai bd phan nho ra cd kich thudc nhd.Bang each sd dung phep co nhi ph8n, lucre bd
cac diem anh ben gan phia ngoai be mat doi tuong, chi git? lai cac phan td ca ban cau
hinh len hinh dang ddi tuong. Td cac ph^n td sau khi co nhi phan ta se sd dung phep
gian nhi phan cung phan td cau true de tac dong len ddi tuong. Cudi cung ta se co
dupe ddi tupng mdi td cac phan td ca ban do.
Phep md cua anh giua tap hop A va phan td cau true B dupe ky hieu A B va
dupe dinh nghla bdi cdng thdc sau:

\

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\ v^i ^^ t^ )

\

B

a^
nn

nn^inri^
nncnii
nnnnn

•nnnnn
nnrsun^ •

, nr.nunnnn
Baa^irana

.r.nnn-

ennnu

r.nnnr^

TBaVfl
ntmtm
ennnn
nnnr

Hinh 2-8: Phep mo anh nhj phan. |S^

Phep dong anh thuc hien 2 giai doan theo thu tu la phep co anh va gian anh vdi
cung mot phan td ciu true cd cung kich thudc (Hinh 2-8).
2.4.5. Phep dong anh (Closing)
Tucmg tu nhu phep md anh, nhung qua trinh thuc hien phep dong anh cd xu
hudng ngupc lai, vdi muc dich lap day nhung chd thieu hut ban dau cua ddi tupng tren
anh dua vao cac phan td ca ban ban dau.

SVTH: Nguyln Tin An - DTH092021


Tim hieu ky thuat nhan dang ky tu so viet tay va ling dung nhap diem to dong

Phep dong anh cua tap hop A bdi phan hi cau true B, ki hieu la A • B, dupe dinh
nghTa bdi cong thuc:

DO. ^ 0 0 :) •* 0. OOOOO
uDDDD .)' >i a ^BDDD

Kll

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0

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il^M^liE
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1 iV A It 1 ' V | 1 * I UUJ
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ilii iim^j
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p f ^n
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TTTBBVI!!

o o uDnDEDDu o n n i) o 3

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o oB3D i ^ i i
' ^ BEID o > jj O o

o o i o *c o
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onnun

onn o i o onnii
ij nnn ^ o ^nn ^
o o nnEinni] o -?

o nn a a •> y
o nnn a o o nn >•>•.• iho
o oBDDDHI] o o n o o o t
ooo o } o o D o *o o o o cr o o-

Hinli 2-9: Phep (long anh nhi phan. |8|

Phep dong anh dau tien thuc hien se md rpng doi tapng bang phep gian nhi phan
theo phan to cau true B. Sau do ap dung phep co nhi phan vdi cung phan to cau true
ban dau de dua doi topng ve trang thai ban dau (Hinh 2-9).
2.4.6. Tim khung xucmg (Skeletonization)
Khung xucmg cua doi topng anh la tap hop cac diem anh each deu bien cua doi

topng, trong luan van nay skeletonization dupe dung de bien cac anh ky to so dau vao
thanh nhung anh net dom (co dp day 1 hay 2 diem anh) chinh vi vay khi cac ky to dupe
viet dudi cac net day hay mdng khac nhau thi qua phuomg phap nay deu chuyen ve
mot chuln nh^t dinh, dilunay giup tang dp chinh xac cho viec nhan dang.
Giai thuat tim khung xucmg co the bieu dien bang phep co va phep md anh.
Xet A la mot anh nhi phan bao gdm cac dilm anh thupc doi topng, dupe dat nhan
la cac so 1, cac diem anh khong thupc doi tapng dupe dat nhan la 0. B la phan to cau
true 3x3. Quatrinh tim khung xucmg dupe xac dinh qua cong thuc dudi day:

Sn(A) = (AQnB) - [{A QnB) o B], n = 1,2JV
Giai thuat se thuc hiSn phep co n Ian tren anh A va n se la budc lap cuoi cung
cho din khi Sn(A) la tap ring. Nhu vay qua trinh co n-1 lln tren anh A se cho anh ciu
true cua A.

SVTH: Nguyin Tdn An - DTH092021

10


Tim hieu ky thuat nhan dang ky tu so viet tay va ling dung nhap diem tu dpng

Vidu hinh 2-10:
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Hinh 2-10: Qua trinh tim khung xmvng ciia anh. [8]
2.5. Loc anh

Qua trinh scan anh vao may tinh co thl gay ra nhilu cho anh s6. Nhilu trong anh
da dang va phuc tap. Nhilu co thl hilu la nhung pMn tu: anh ma gia tri ciia no n6i trpi
so vdi cjic phln hi anh xung quanh, hay la nhung ph^n hi anh du thira ma chiing ta
khong can den trong qua trinh su dung anh. Be loai bo nhieu chiing ta sii dung cac ky
thuat loc anh. Trong bao cao nay de cap den 2 loai loc anh la: lpc trung vi va loc cac
thanh phSn lien thong Ion va nho.
2.5.1. Lpc trung vi

Ky thupt lpc nay kha hieu qua cho cac loai nhilu nhu: nhilu dim (speckle noise)
va nhieu muoi tieu (salt-pepper noise)
Y tudng chinh cua thuat toan lpc Trung vi (Hinh 2-11) nhu sau: ta su dung mot
cua s6 lpc (ma tran 3x3) quet qua lln lupt timg dilm anh cua anh dSu vao input. Tai vi
tri moi diem anh lay gia tri cua cac diem anh tucmg ling trong vung 3x3 cua anh goc
"lap" vao ma tran lpc. Sau do sip xlp cac dilm anh trong cua so nay theo thii tu (tang
dan hoac giam dan tuy y). Culi cung, gan dilm anh nlm chinh giua (Trung vi) ciia day
gi^ tri diem anh da dupe sap xlp d tren cho gia tri dilm anh dang xet ciia anh dlu ra
output.

SVTH: Nguyln Tin An - DTH092021

11

Tim hieu ky thuat nhan dang ky tu so viet tay va ling dung nhap diem tu dpng

4A

plian t^
tiungvj
sans ^^p
xep
Hinh 2-11: Loc truiig vi

2.5.2. KM thanh phin lien thong ldn va nho
Vai cac nhieu vet (hoac cac nhieu co kich thircrc Ion) (Hinh 2-12) thi phuong
phap loc tmng vi to ra kem hieu quil, trong truong hop nay ta sir dung them phucmg
phap khir cac thanh phan li&i thong lcm va nho.
Ky thuat nay duoc sir dung rieng cho viec loai bo cac nhieu xac dinh khong
thupc thanh phan anh cua doi tuong can lay. Bang each do cac kich thurac cua cac
thanh phan lien thong tren anh, ta se so sanh chung vdi cac kich thudc udc lupng trtrdc
de xac dinh chung co phai la nhieu can loai bo hay khong.

*^\

B

o

Hinh 2-12: Nhieu dom va nhieu vet dai. 112|

2.6. Lu^c do cliieu (Histogram)

Trong npi dung bao cao nay, sir dung chu yeu 3 loai lupc do chieu la: liroc do
mire xam, lupc do chieu ngang, lupc do chieu doc.
2.6.1. Lupc do muc xam

Lupc d6 miic xam (Gray-Scale Histogram) (Hinh 2-13) th^ hien sir dac trung
phan b6 cua cac gia tri mric xam ciia mot anh. Lupc d6 nay vai true hoanh la dp sang
va true tung la s6 lupng diSm anh cr nhung dp sang tuomg ung. Thong qua tin so cua
cac muc cuong dp xam ta thiy dupe muc dp tuomg phan cua anh. Lupc d6 nay phuc
vu chu ygu cho muc dich tim nguang nhi phan anh trong thuat toan Otsu.

SVTH: Nguyen Tan An - DTH092021

12


Tim hieu ky thuat nhan dang ky tu so viet tay va ung dung nhap diem tu dong

TTinh 2-13: Lmrc do mire xam.

2.6.2. Luge do chieu ngang va lucre do chieu doc

Lucre do chieu doc (Vertical Histogram) ya lucre d6 chi6u ngang (Horizotal
Histogram) hai loai lucre do nay xay dung cho doi tuong la anh nhi phan nhlm th6ng
ke cac diem anh theo chieu doc hay chi6u ngang. Hai luac d6 nay ling dung chu yeu
trong phan tach cac thanh phan b^ng diem trong phan xay dung ling dung sau cua luan
van nay.

Lay lucre do chieu ngang bang each duyet ttr tren xuong duai va tir trai qua phai
cua anh, qua moi dong pixel ta se tien hanh cong d6n so pixel den tren tung dong. So
pixel den tren timg dong se dugc bieu dien thanh mot do thi voi true nam doc la chieu

cao cua anh con true nam ngang la so pixel den diem dugc tren dong. Thong qua luge
do nay ta co the nhan thay dugc su phan each giua cac khoi van ban giua cac dong vdi
nhau.

Tru"6ng Dai Hoc An Giang

Phong KhaoThf&KDCL
Hinli 2-14: Luoc do chieu ngang.

Lay luge do chieu doc bang each duyet chiing theo chieu dgc, ling voi moi cot ta
se cong don so pixel den. Tren luge do true Oy se la s6 pixel den tren mot moi cot va
true Ox la chieu rgng cua anh. Thong qua luge do nay ta co the nhSn thay dugc su
phan each giiia cac khoi van ban gitia cac dong voi nhau.

TrtfoFng Da! Hoc An Giang
Hinh 2-15: Liroc do chieu doc

2.7. Giai thuat to mail theo dong quet cai ti^n
Cac dinh nghia

SVTH: Nguyen Tan An - DTH092021

13


Tim hieu ky thuat nhan dang ky tu so viet tay va ung dung nhap diem tu dong

•Mot vung to bao gom dudng bien va vung ben trong. Duong bien la mot dubng
khep kin, vi du nhu da giac.
•To mau la thao tac tim cac- diem sang "nam ben trong" mot vimg to.

•To dua theo dong quet (scan line) la to mau theo dong dilm sang tren man hinh.
Cach thuc hien:
Thuat toan to mau theo ducmg bien
Duong bien trong thuat toan nay dupe mo ta biing mot gia tri duy nhat la mau
cua tat ca cac diem thuoc ve dubng bien.
Bat dau tir mot diem nam ben trong vung to, ta se kiem tra cac diem Ian can cua

no da duoc to mau hay co phai la diem bien hay khong, neu khong phai la diem da to
va khong phai la diem bien, ta se to mau no. Qua trinh nay duoc thuc hien lap di lap lai
cho den khi nao khong con to duoc di^m nao nua thi dimg. Bang each nay, toan bo cac
diem thupc vung to dupe kiem tra va to het.

Hinh 2-16: To mao theo dirolig bien.[19]

Co 2 quan diem ve each to nay, do la dung 4 diem Ian can (co the gpi la 4 lien
thong) hay 8 Ian can (8 lien thong).

4 lin thdng8 li^n thong
Hinh 2-17: Hai each to mau dting 4 lien thong va 8 lien thong.

Trong npi dung bai luan ^n nay sir dung each to 8 lien thong de xac dinh cac
thanh phan lien thong trong anh.
Do thuat toan nay khi cai dat co tinh de quy nen thuong dan den viec tran bp nhd
d6i vdi cac vung to kha Ion. DS khic phuc vi^e tran bp nhd ta su dung tinh chat cua
stack de khu de qui trong viec lap trinh.
2.8. Ap dung phrnmg phap Hough tim goc nghieng cua anh
- Thuat toan Hough Transform co ban

SVTH: Nguyen T^n An - DTH092021

14


Tim hieu ky thuat nhan dang ky tu so viet tay va ung dung nhap diem tyr dong
Ta co phnong trinh durdng thing Hough trong toa do cue (Hinh 2-18) co dang
nhu sau:
y = mx + b

/y — mx + b

Hinh 2-18: Phmmg trinh dirong thing tr^n he toa do Decard.[19]

Vdi m va b la 2 so thuc bat ky, trong do m dupe xem la he so goc xac dinh goc
ctla dufrng thang so vdi true hoanh va b xac dinh vi tri dudng thang cat true tung.
Nhu vay, vdi mot diim co toa dp (xl,yl) xac dinh, ta se co thi tim ra dupe vo s6
cap (m,b) ting voi ducmg thing co thS di qua diim (xl, yl) do, sao cho m va b thoa
m3n dieu kien sau:
b = yl - mxl

Uiig dung phuoug trinh xac dinh ducmg thing tren vao anh nhi phan vdd m6i
diim anh tren anh nhi phan xem la 1 di6m cin xac dinh cac ducmg thing di qua diem
anh nay, nhu vay vai m5i diSm anh den se xac dinh dupe vo so ducmg thing di qua
diem anh nay.

- t/ng dung thuat toan Hough vao viec xac dinh goc nghieng cua anh bing each
ta su dung mang tich luy co kich thudc (m,b) dl dim s6 Ian ducmg thing dupe tao bdi
cap gia tri (m,b) qua m5i diim anh, goc nghieng cua bang diim se la goc co tong gia
tri cua mang tich luy tai cap m,b co gia tri cue dai.
Tuy nhien vdi m va b trong phuang trinh b = y - mx khong bi gidi han, diiu nay

co nghia ring, khi m tiin din vo cue thi b cung tiin din den vo cue. Do do, viec su

dung mang 2 chiiu (la co gidi han) di biiu diin (m,b) (khong cd gidi han) diiu nay
khong thi thuc Men dupe. Ngoai ra chi si cua mang khong dupe am. Di vupt qua khd
khan nay ta su dung bieu dien dang chuan cua dudng thang dudi dang:
X*cosA+y*cosA = B

SVTH: Nguyen Tan An - DTH09202115


Tim hieu ky thuat nhan dang ky tir so viet tay va ting dung nhap diem tu dong

B

Hinb 2-19: Phuong trinh ttiio-ng thsing Hongh.[l9|

Trong do
-A la so do cua goc tao bdi dudng thang vdi true hoanh, gia tri kieu so thyc
(Hinh2-19).
-B la khoang each tir dudng thang do den goc tpa do (ap dung trong bao cao nay
la goc tren trai cua anh), kieu so thuc.
Cong thirc nay cung co the bieu dien mpi duong thang bat ky trong khong gian 2
chieu nhu cong thutc y= mx+b nhung 2 tham so A va B cua no co gidi han trong anh 2

chilu:
Gidi h^n cua A se la gidi han goc nghieng cua anh can tinh
B dupe gidi han tir 0 den chieu dai dudng cheo cua anh.
2.9. Chuan hoa kich thirdc
Do anh dlu vao thudng co cac kich co khac nhau, vi vay sau khi tach cac ky tu ra
thi chiing cung cd kich cd khac nhau, vi vay de tang dp chinh xac cho viec nhan dang,

ta can chuan hda cac ky tu ve cung mot kich thudc dinh trudc. Trong bao cao nay
chiing toi sir dung kich thudc la 16xl6px, vdi kich thudc nay se phuc vu tot cho viec
trich chpn dac trung.

SVTH: Nguyln Tin An - DTH092021

16


Tim hieu ky thuat nhan dang ky tu so viet tay va ting dung nhap diem tu dong-

CHLTONG 3: PHAN LOT V6l SVM VA MANG NO-RON NHAN TAO
3.1. Gio'i thieu bai toan phan lop
Hien nay cac bai toan nhan dang mlu vdi d^^u vao la anh s6 kha da dang nhu
nhan dang mat ngudi, nhan dang dau van tay, nhan dang chit viet,... cac bai toan nay

la mot trong nhung ting dung phd bien cua bai toan phan lop!
Phan ldp la la tim ra mot chien lucre nham phan loai mau vao cac lop co san mot
each tot nhat, trong do mdi ddi tupng trong mau co mot nhan, nhan nay chinh la ldp no
thupc vd, txr do xay dung nen mot mo hinh phan ldp. Vi vay khi dua 1 du lieu cua mOt
d6i tupng mdi vao mo hinh phan ldp nay, mo hinh se nhan dang dupe du lieu cua d6i
tupng nay thudc ldp nao.
Co nhidu phuong phap phan ldp khac nhau nhu: cay quydt dinh, ngubi lang
gidng gan nhat, mang neural nhan tao, may hoc vector h tro SVM, phan cum dfl
lieu,.... Doi vdi bai toan nhan dang lien quan d^n ky tu quang hoc, ky tu viSt tay, chu
viet thi hai phuong phap duoc ling dung nhieu tir trudc den nay la may hoc vector ho
trp SVM va mang neural nhan tao.

3.2. Phan lop vdi SVM
3.2.1. Trich chon dac trung waveletHaar

Trong hau het cac he nhan dang, de tang do chinh xac va giam do phdc tap cua
cac thuat toan phan ldp thi doi hoi du lieu dua vao bp phan ldp phai dupe rut gpn lai
cang nho cang tot nhung phai dam bao dupe thong tin dac trung cua mdi mlu dti lieu.
Vdi muc tieu nay, mot tap cac dac trung dupe trich chpn cho mdi ldp sao cho cd the
phan biet ldp nay vdi cac ldp khac. Trich chpn dac trung se trich ra nhirng thupc tinh
cua doi tupng dudi dang cac dp do, tir do xay dung nen cac md hinh nguyen miu
chung cho cac ldp ddi tupng. Va do do trich chpn dac trung se cd gang tim ra cac
thupc tinh dua tren nguyen mau da xay dung cho cac ldp.
Cd nhidu phuong phap trich chpn dac trung nhu phep bidn ddi Fourier, bidn ddi
Wavelet Haar, trong so vimg (Zoning), bidu dd chidu (Projection histograms), trich
chpn chu tuyen (Countour profiles),....

Trong bao cdo nay chung tdi su dung phuong phap trich chpn dac trung Wavelet
Haar, phep bien ddi nay la mot day cac ky thu$t khai trien cho phep md ta dac trung
cua anh d cac muc dp khac nhau.
ooooooaooiiioooo
0000000011110000
0000000011110000
000 00001 11110 000
000 0001 11011
000
000000111001
000
0000 0.1 110001
10 0
0000011100001100
0000111111111100
0001111111111110
0011100000000110

0011100000000111
0111000000000011
1110000000000011
iiioooooooooooii
1100000000000011

30000000011 1 O DOC
000000001 111DOOC
000 000001 illo ooc
1 1 C-IOOC
Doocp^ooi 1101
^?:^O
0DO^^D1 1
00000011 1DOI1OOC
oooooiii 0001110C
00000111 0000110
oooo1Tii 1111110
00011111 1 1 1 1 1 1 1 C
00111000000001 1 C
00 0 00
111
^VbQOOOO:
'Oil
111 0000000000011
111 00 00 000000011
11 00000000000011

IS42

Hinh 3-1: Trich chon dac tinng waveletHaar.[181

SVTH: Nguyln Tin An - DTI M

G DAI HQC
GIANG

THLfVIEN

17