Tìm hiểu kỹ thuật nhận dạng ký tự số viết tay và ứng dụng nhập điểm tự động

Trong bao cao nay, chung toi se trinh bay t6ng quan til viec thu thap dft lieu din mots6 ky thuat xu ly anh ky tu d^u vao va xay dung bo phan ldp tren phuong phap mayhoc vec-to h trp va

An Giang, 05/2013

Giang vien huong danTS.NguyinVanHoaTHUVIEN

TR^CiNG DAI HOC

AN GIANG

TU SO VIET TAY VA ifNG DUNG NHAP

Nguyin Tin An

LOI CAM ONDlu tien em xin giii lbi cam cm din cac thiy co da tSn tinh giang day truyln dat kilnthiic 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 denthay giao, tien si Nguyen Van Hoa nguoi da tan tinh hudng dan em trong suot quatrinh thurc hien bai bao cao nay

Em cung xm bay to loi cam cm sau sic din thly Huynh Ly Thanh Nhan nguoi da taonen tang lap trinh cho em va anh Nguyen Duy Dat nguoi da tan tinh goi y giiip d& emtrong 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 trongsuot qua trinh thurc hien

Em xin chan thanh cam an.

Tp LongXuyen, ngay 18 thdng 5 nam 2013

Sinh vien

TOM TATNhan dang ky tu dac biet la ki tu viet tay v&n chua co dupe mot giai phap tong the, cacling dungcua no cung chi gioi han trong pham vi hep, bai toan nay chua the giai quyettrpn 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 mots6 ky thuat xu ly anh ky tu d^u vao va xay dung bo phan ldp tren phuong phap mayhoc vec-to h trp va mang no-ron nhan tao dl giai quyet bai toan nhan dpg ky tu, tuynhien do su phirc tap cua viec nhan dang tap ky tu viSt tay va giai han vS ki^n thiic vathai gian nen a bao cao nay chiing t6i chi tien hanh xii ly nhan dang tren tap ky tu soviet tay Phan thii hai ciia bao cao thuc hien xay dung ling dung nhap diem tu dpngdua 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, tachanh 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 khoibang 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 soviSt 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 soviet tay va 15 bang dilm mlu dl lam kilm tra cho ling dung nhap diem tu dpng

MUCLUC CHUtSNGLTONGQUAN1l.l.Ly dochond^tai'11.2.B6i tugng va pham vi he thong1

1.3.Muctieu2

CHITONG 2: CO SCS LY THUYET32.1.Khainiemvganhs632.2.Phucmg phap tim nguong Otsu cho nhi phan hoa anh42.3.Thanh phfin lien thong trong anh nhi phan52.4.Phep toan hinh thai hoc (Morphology)62.4.1.Phan tu cau tnic (structing element)72.4.2.Phep gian nhi phan (Dilation)72.4.3.Phep co nhi phan (Erotion)82.4.4.Phep m^ anh (Opening)92.4.5.Phep dong anh (Closing)92.4.6.Tim khung xvrong (Skeletonization)10

2.5.Lpcanh11 2.5.1.Lpctrung vi11

2.5.2.KM thanh phdn lien thong ldm va nho122.6.Luge d6 chiSu (Histogram)12

2.6.1.Luge d6 miic xam12

2.6.2.Luge d6 chieu ngang va luge d6 chiSu doc132.7.Giai thuat to mau theo dong quet cai ti^n132.8.Ap dung phuong phap Hough tim goc nghieng cua anh142.9.ChuSn hoa kich thudc16CHHONG 3: PHAN LCJP VCil SVM VAMANGNO-RONNHANTAO173.1.Giai thieubai toan phan ldrp173.2.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)34CHHONG 4: NIDI DUNG THUC HIEN VA KET QUA NHAN DANG KY TH SO VIETTAY36

4.1.Mo hinh bai toan364.2.Qua trinh ti&i xii ly374.2.1.Lpctrungvi (Median Filter)374.2.2.Xam hoa anh (GrayScale Image)384.2.3.Nhi phan hoa (Binary Image)384.2.4.Phep toan hinh thai (Morphology)394.2.5.Tim gioi han cac ky tu (Get boundary box)394.2.6.Gpp cac thanh ph^n lien thong gta (Merge connections)414.2.7.Loc thanh phiin lien thong lorn va nho (Filter connections)444.2.8.Tach va chu&i hoa kich thuoc anh (Drop and resize)464.2.9.Lay xuong cua anh (Skeletonilation)464.3.Thu thap tap dft lieu464.4.Xay dung bp phan lop SVM494.4.1.Trich chpn dac trung494.4.2.Chien lupc xay dung bp phan lop494.5.Xay dung bp phan lop bang mang No-ron MLP494.6.KSt qua thu nghiem50CHl/ONG 5: LlNG DUNG NHAP DIEM TU DONG54

5.1.M6tabaitoan'.54

5.2.Co so ly thuy^t xii ly bang di^m555.2.1.Mo ta bang di6m555.2.2.Mo hinh bai toan575.3.Cai dat chuong trinh595.3.1.Qua trinh chinh nghieng anh bang diem595.3.2.Qua trinh tach khoi bang diem605.3.3.Qua trinh tach thong tin va trang cua bang diem675.3.4.Qua trinh xay dung bp phan lop695.4.K6t qua xu ly nhap diSm tvr dpng69CHUONG 6: KET LUAN VA HU6NG PHAT TRIEN756.1.Kit qua dat dupe:756.2.Huong phat trien75

DANH SACH HEVH VEHinh2-1: Anhnhiphan; (A) anh dau vao, (B) anhnhiphan3Hinh 2-2: Phucmg phap nhi phan anh; (A) Histogram cua anh da capxam nguyenban,(B) ngu&ng thip, (C) nguomg thich hop, (D) nguang cao.[22]4Hinh 2-3: Thanh phan lien thong vdi 4 va 8 ketnoi6Hinh 2-4: Thanh phdn lien thong trong anh6Hinh 2-5: Cac loai pMn tu cu true7Hinh 2-6: Phep gian nhi phan [8]8Hinh 2-7: Phep co nhi phan [8]8Hinh 2-8: Phep md anh nhi phan [8]9Hinh 2-9: Phep dong anh nhi phan [8]10Hinh 2-10: Qua trinh tim khung xurong cua anh [8]11Hinh 2-1 l:Lpc trung vi12Hinh 2-12: NhiludOmvanhiSu vet dai [12]12Hinh 2-13: LupcdOmucxam13Hinh 2-14: Lucre d6 chiSungang13Hinh 2-15: Lucre do chieudpc13Hinh 2-16: TO mau theo duomgbien.[19]14Hinh 2-17: Hai each tO mau dung 4 lien thOng va 8 lien thOng14Hinh 2-18: Phucmg trinh duomg thing tren he tpa dp Decard.[19]15Hinh 2-19: Phuomg trinh duong thing Hough.[19]16Hinh 3-1: Trichchpndac trung waveletHaar.[18]17Hinh 3-2: Day dactrungwaveletHaar.fi8]18

Hinh 3-3: PhSnlopSVM.fi]19

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

Hinh 3-9: Mang na-ron nhan tao27

Hinh 3-10: M0 hinh mang mot lop29Hinh 3-11: Vi du ve mot mO hinh mang na-ron da tang29Hinh 3-12: Mang na-ron perceptron30Hinh 3-13: Mang na-ron MLP31Hinh 3-14: Luu dO giai thuat Ian truyOn nguac huan luyen mang MLP33Hinh 3-15: vi du dinh dang tap du lieu cua thu vien FANN35Hinh 4-1: M0 hinh bai toan36Hinh 4-2: Anh ky tu dau vao36Hinh 4-3: Qua trinh tiOnxuly37

Hinh 4-4: Anh bi nhiOu dOm37

Hinh 4-5: Anh sau khi loc trung vi38Hinh 4-6: Xdm hoa anh; (A) anh diu vao, (B) anh da ltai xam38Hinh 4-7: Anh sau khi nhi phan38Hinh 4-8: Phep dong anh; (A) anh sau khi nhi phan, (B) anh sau khi sur dung phepdong anh39Hinh 4-9: Hinh chu nhat giori han cac ky tir s639Hinh 4-10: Liru d6 tim giai han ki tu41Hinh 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 thong42Hinh 4-12: Lira d6 giai thuat gpp cac thanh phin lien thOng g^n43Hinh 4-13: Lira do giai thuat xac djnh hai hinh chd nhat giao nhau44Hinh 4-14: Lira d6 giai thuat lpc thanh ph^n lien thong ldn va nho 45Hinh 4-15: L^y xuong cua anh46Hinh 4-16: Tap dtt lieu s6 047Hinh 4-17: Tap da lieu s6 948Hinh 5-1: Qua trinh cua he th6ng nhap di6m to dpng54Hinh 5-2: Anh bang dilm56Hinh 5-3: Mo hinh xuly57Hinh 5-4: Mot s6 dirong thing Hough ke theo each co ban59Hinh 5-5: Duong thing Hough ke theo phuong phap cai ti^n59Hinh 5-6: Lupc d6 chi6u ngang cua anh bang diim; (A) Lupc d6 ban diu, (B) Lupc d6sau khi su dung phep toan hinh thai61Hinh 5-7: Lupc do chieu doc ciia khoi bang diem62Hinh 5-8: Lupc d6 chiSu ngang cua khoi bang dilm63Hinh 5-9: Anh cac ky tu MSSV bj dinh nhau64Hinh 5-10: Cac thanh phin cin tach trong kh6i thong tin va trang cua bang diSm67Hinh 5-11: Lupc do chieu ngang cua khoi thong tin bang diem67Hinh 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 252Bang 4-5: Ma tran confusion ket qua nhan dang bang mang no-ron ISn 352Bang 5-1: Bang ket qua cac qua trinh tach bang diem ban dau70Bang 5-2: Bang kit qua chi tilt phln nhan dang ky tu in trong MSSV71Bang 5-3: Bang kit qua tach ky tu va nhan dang MSSV71Bang 5-4: Kit qua cua qua trinh tach ky tu dilm si71Bang 5-5: Ma tran confusion ket qua nhan dang diem so da tach va khong xoa dubnggach 6 dilm bang svm72Bang 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 dubnggach 6 dilm bang mang no-ron73Bang 5-8: Ma tran confusion ket qua nhan dang diem s6 da tach va xoa dubng gach 6dilm bang mang na-ron73

SVTH: Nguyen TSn An - DTH092021

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 cothi nhan biet dirge cac ky tu Cac ky tu nay co the dugc tao ra bang may hay dugc taobdi 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 tuviet 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 nhieukhd khan nhu khong co khai niem font chu chung, kich thudc chu, dp rpng hep, caothip cung khac nhau, dp nghieng do each viSt cua mi ngucri khac nhau, , ved nhungygu t6 nhu vay se lam cho s6 mlu d^u vao ion, va gitta nhi8u mlu dau vao cua cungmot 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 baitoan nhan dang ky tu, va phuong phap may hoc pho bien nhat trong nhan dang ky tuthudng dugc ung dung la mang na-ron nhan tao (Artifical Neural Network) va ti lethanh cong cua phuong phap nay d nhilu cong trinh cung dat dugc khd cao nhu henhan dang chu in dua tren mo hinh mang neuron bon ldp cua hai tac gia Wang va Jeantrong [1] cd ty le nhan dang chinh xac tdi 99,81% V^ nhung nam gan day mot phuongphap khac trong linh vuc khai khoang du lieu thudng dugc ap dung cho bai toan nay laphuong 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 lydau vao cung rat quan trong, qua trinh xu ly tot se giup cho tap du lieu mau cho quatrinh 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 vathdi gian thuc hien cung nhu viec thu thap tap d^ lieu mau con nhieu han che va chothfiy 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 sedugc tir thu thap, sau do tim hiiu ky thuat xu ly phan tich anh dlu vao va sir dung bpmay 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 viettay trong phln ung dung nhan dang dilm tu phieu dilm, ben canh nhan dang, trongung dung nay cung tap trung nghien cuu vao qua trinh xu ly tach anh van ban

SVTH: Nguygn 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 vanban 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: Nguyen Tan An - BTH092021

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 thuchien qua trinh phan tich va nhan dang chung ta can phai chuyen chung thanh anh nhiphan 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 tuanh mau RBG sang anh xam 8bits thubng sir dung mot trong 2 cong thuc sau, ap dungcho 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

CB) (A)

^ OX X1 l-i i OOOoo a^ XI1

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, maytinh 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 hemau 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 xanhluc (green) cong xanh duong (blue) Moi mau co gia tri tir 0 den 255, nghia lamoi 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^nghoac den Khi xh ly tren may tinh thi ngubi ta dung anh xam d^ bi^u diln anhnhi phan va luc nay 2 gia tri la 0 hoac 255, gia tri 0 bi^u diln cho mau den vagia tri 255 bilu diin cho mau tr5ng (Hmh 2-1)

SVTH: Nguyln Tin An - DTH092021

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 nguongtoi 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 thienciia tap du lieu theo khong gian va thai gian, thong thuong dupe xac dinh thong quaviec kh^o sat tap du lieu bSng cac phuong phap thbng ke Trong npi dung luan van naychung 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 dpavao lupc do xam cua ^nh Thuat toan gia dinh ring anh se g6m 2 thanh phan la phlnanh va phan nen, vi vay nguong t6i uu la ngu&ng co thl phan tach 2 thanh nay moteach ro nhat va lam giam thi^u s6 chi tiSt d6i tupng anh bi mit

Topping the

Tqtant of Russia's SdenKsts, p.5

o(trar^

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:

pt la xac suat cua mot miic xam i

a;- la tong xac suat tren doan j

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 lienth6ng 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 anhphai 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

Nh5ng 6 man x^m ttrpngtrung cho diim anh co gia

Pj 1, nhung 6 mau trfingtupng trung cho diem anhc6 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 lienthong 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 dlitupng Pong anh Nhiing dli tupng Pong hinh thai hoc ta co thl coi nhu la tap hop cuacac diem anh, nhom lai theo ciu true ma Pan 2 chilu Nhung thao tac toan hoc rai racPen tap hop diem do dupe su dung dl lam ro nhung net dac trung rieng cua hinh dangd6i 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)

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 quatung diem anh, diem tai trung tam (tam goi la C) dupe gan la 1 khi tai diem anh do cogia 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

(b) 8 n6i kit(a) 4 n& kit

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

SVTH: Nguyen Tan An - DTH092021

Nhu vay phep gian nhi phan ciia trip hop A boi phan tix cau tnic B la tap hop cuatit 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 diemanh trong anh nguon Neu ton tai mot diem anh cua ddi tuqng nam trong B thi gan gia

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 mauxam dupe xem la cac di&n anh ciia ph^n hi cSu tnic, cac 6 mau trang xem la nen cothfi xem chiing khong phu thupc vao ph^n tir ciu tnic.Khi mot phep toan hinh thaidupe thuc hien thi tam cua ph^n hi cSu tnic thudng dich chuyln Ian lupt tren cac dilmanh Va khi do cac gia tri diem anh vita dupe quet qua se dupe so sanh vdi nhau, cacket 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:

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 conhi 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 motphan 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 dpciia mot so diem lien quan ten doi tupng nao do Dudi day la mot vai mau dac trungcho cac phan tu cau tnic co kich thudc khac nhau:

SVTH: Nguyln Tdn An - DTH092021

Hinh 2-7: Phep co nhi phnn |8|

Dnnnnnnn

If

BSBs

5111

nrnnnnnn

nnc^itrtnnn nnnnnn

A(JLQB)

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 phanlien 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 thanhlien 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 vaviet dudi dang cdng thiic nhu sau:

SVTH: Nguyln Tin An - DTH092021

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 vdicung 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 xuhudng 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.

ntmtm ennnn nnnr

•nnnnn nnrsun^ •

, nr.nunnnn Baa^irana

2.4.4 Phep md anh (Opening)

Phep md anh thudng dung dl lam tran cac dudng bien cua doi tupng anh, nhuloai bd phan nho ra cd kich thudc nhd.Bang each sd dung phep co nhi ph8n, lucre bdcac diem anh ben gan phia ngoai be mat doi tuong, chi git? lai cac phan td ca ban cauhinh len hinh dang ddi tuong Td cac ph^n td sau khi co nhi phan ta se sd dung phepgian nhi phan cung phan td cau true de tac dong len ddi tuong Cudi cung ta se codupe 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 vadupe dinh nghla bdi cdng thdc sau:

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

SVTH: Nguyin Tdn An - DTH092021

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 phantheo phan to cau true B Sau do ap dung phep co nhi phan vdi cung phan to cau trueban 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 doitopng, trong luan van nay skeletonization dupe dung de bien cac anh ky to so dau vaothanh nhung anh net dom (co dp day 1 hay 2 diem anh) chinh vi vay khi cac ky to dupeviet dudi cac net day hay mdng khac nhau thi qua phuomg phap nay deu chuyen vemot 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 cautrue 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 cungcho 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.

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-

ilii iim^j

iMvliBB

* I UUJ il^M^liE

QS| 0 0 0 0

nnnno

nnnnni 1

in

1

11

| i^

2t' 'V

if

HI

ill

1

V-BBR

-It 1

o 0 0

n

I^

A 1

3 0 t>

^

1 iV 1

u n

o

T

1 1 1

Kll

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 dinhnghTa bdi cong thuc:

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 takhong can den trong qua trinh su dung anh Be loai bo nhieu chiing ta sii dung cac kythuat loc anh Trong bao cao nay de cap den 2 loai loc anh la: lpc trung vi va loc cacthanh 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 motcua s6 lpc (ma tran 3x3) quet qua lln lupt timg dilm anh cua anh dSu vao input Tai vitri 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 (tangdan hoac giam dan tuy y) Culi cung, gan dilm anh nlm chinh giua (Trung vi) ciia daygi^ tri diem anh da dupe sap xlp d tren cho gia tri dilm anh dang xet ciia anh dlu ra

output.

q q q q q q a 0 0

0 a 0 0 0 0 0 0 0

0 0 0 0 0 0 0

til

0

0

0 0 0 0 0 0

0 0 0 0 0 0 0

Si

0

0 0 0 0 0 0 a 0 0

a 0 0 0 0 0 0 0 0

q 0 0 q q

q

0 0 0

0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0

0 0

p

0 0 0 0 0 0

0 0 0 0 0 D 0 0 0

0 0 0 0 0

q

0 0 0

0 0 a 0 0 0 0 0 0

0 0 0 0 0 a 0 0 0

D 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0

0 0 0 0 a 0 0 0 0

0 0 0 Oi 0 0 0 0 0

0 0 0 0 0 0 0 0 0

0 a 0 0 a 0 0.

0 0

0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0

0 0 0 0 D 0 ll

fi

0

0 0 0 0 0 0 0

0 0 0 0 0 0 a

0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0

Si:

0

0 0, 0 0 0 0 0

m

0

0

m m s

IS

0

0 0 0 a 0 0 0

si

0

0 0 0 0 0 0 0 0 0

0 a 0 0 0 0 a 0 a

0 a 0 a 0 0 0 0 0

0 0 0 0 0 0W

Rl

^K

0 0 0 0 0 0

fil

Si it

si

SI

© si'ti

?iM

12SVTH: Nguyen Tan An - DTH092021

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 trungphan 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 cuacac 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

o

*^\

B

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 phuongphap loc tmng vi to ra kem hieu quil, trong truong hop nay ta sir dung them phucmgphap 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 khongthupc thanh phan anh cua doi tuong can lay Bang each do cac kich thurac cua cacthanh 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

plian t^

tiungvjsans ^^pxep

4 A

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

13SVTH: Nguyen Tan An - DTH092021

Hinh 2-15: Liroc do chieu doc

2.7 Giai thuat to mail theo dong quet cai ti^n

Cac dinh nghia

TrtfoFng Da! Hoc An Giang

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 vatrue Ox la chieu rgng cua anh Thong qua luge do nay ta co the nhSn thay dugc suphan each giiia cac khoi van ban gitia cac dong voi nhau

Tru"6ng Dai Hoc An Giang

Phong KhaoThf&KDCL

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 (HorizotalHistogram) 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 yeutrong 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 phaicua anh, qua moi dong pixel ta se tien hanh cong d6n so pixel den tren tung dong Sopixel den tren timg dong se dugc bieu dien thanh mot do thi voi true nam doc la chieucao 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.

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

SVTH: Nguyen T^n An - DTH092021

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 cacthanh phan lien thong trong anh

Do thuat toan nay khi cai dat co tinh de quy nen thuong dan den viec tran bp nhdd6i vdi cac vung to kha Ion DS khic phuc vi^e tran bp nhd ta su dung tinh chat cuastack 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

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 lienthong) hay 8 Ian can (8 lien thong)

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 dubngkhep 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 laicho den khi nao khong con to duoc di^m nao nua thi dimg Bang each nay, toan bo cacdiem thupc vung to dupe kiem tra va to het

SVTH: Nguyen Tan An - DTH09202115

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 gocctla 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 s6cap (m,b) ting voi ducmg thing co thS di qua diim (xl, yl) do, sao cho m va b thoam3n dieu kien sau:

b = yl - mxl

Uiig dung phuoug trinh xac dinh ducmg thing tren vao anh nhi phan vdd m6idiim anh tren anh nhi phan xem la 1 di6m cin xac dinh cac ducmg thing di qua diemanh 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 bdicap gia tri (m,b) qua m5i diim anh, goc nghieng cua bang diim se la goc co tong giatri 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 khdkhan nay ta su dung bieu dien dang chuan cua dudng thang dudi dang:

X*cosA+y*cosA = B

/y — mx + b

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

-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 2chieu 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 rathi 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 naychiing toi sir dung kich thudc la 16xl6px, vdi kich thudc nay se phuc vu tot cho viectrich chpn dac trung

B

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

THLfVIEN

G DAI HQC GIANG SVTH: Nguyln Tin An - DTI M

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

IS42

1111110

1 1 1 1 1 1 1 C

1 C 111 'Oil 0000000000011

00 00 000000011 00000000000011

00 0 00

^VbQOOOO:

111 111 11

oooo1Tii 00011111 00111000000001

1 O DOC 111DOOC illo ooc

1 1 1 C-IOOC

101 ^?:^O 1DOI1OOC 0001110C 0000110

30000000011 000000001

000 000001

Doocp^ooi

0DO^^D1 1 00000011 oooooiii 00000111 0000011100001100

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 cuacac thuat toan phan ldp thi doi hoi du lieu dua vao bp phan ldp phai dupe rut gpn laicang 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 thephan biet ldp nay vdi cac ldp khac Trich chpn dac trung se trich ra nhirng thupc tinhcua doi tupng dudi dang cac dp do, tir do xay dung nen cac md hinh nguyen miuchung cho cac ldp ddi tupng Va do do trich chpn dac trung se cd gang tim ra cacthupc 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 ddiWavelet 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 WaveletHaar, 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.

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 TAO3.1 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 moteach tot nhat, trong do mdi ddi tupng trong mau co mot nhan, nhan nay chinh la ldp nothupc vd, txr do xay dung nen mot mo hinh phan ldp Vi vay khi dua 1 du lieu cua mOtd6i tupng mdi vao mo hinh phan ldp nay, mo hinh se nhan dang dupe du lieu cua d6itupng nay thudc ldp nao

Co nhidu phuong phap phan ldp khac nhau nhu: cay quydt dinh, ngubi langgidng gan nhat, mang neural nhan tao, may hoc vector h tro SVM, phan cum dfllieu, Doi vdi bai toan nhan dang lien quan d^n ky tu quang hoc, ky tu viSt tay, chuviet thi hai phuong phap duoc ling dung nhieu tir trudc den nay la may hoc vector ho

trp SVM va mang neural nhan tao.

SVTH: Nguyen Tan An - DTH09202118

Hinh 3-2: Day dac tnmg vvaveletHaar.118]

Theo phuong phap trich chon dac trung cua thuat toan nay thi ma tr^n A bit biind6i vdi cac dac trung duoc trich chon Tinh chit bit biin nay duoc chiing minh trong

[3].

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

Tir anh nhi phan kich thudc 2n X 2n (hinh) qua trinh trich chon dac trung dugcm6 ta theo thuat toan sau:

Procedure waveletHaarFeature

Bau vao: Ma tran vuong (A,n) cap 2n

Bau ra: Tap cac dac trung {F1; F2, ,

p2"+2™}-Phuong thuc

Khdi tao: Queue = 0; i = 1;

Tinh F,-= Tong cac diem den trong toan bo ma tran (A, n) ;

3.2.2.1 SVMtuyln tinh

SVM tuyen tinh la tradng hop cd the pMn chia tuyen tinh tap du lieu bang motsieu phang Hay ndi each khac la nlu tin tai mot ham tuyen tinh f(x) = w x + b dltach tap du lieu nhi phan thanh 2 ldp

- Sieu phang va cue dai hda le

Nhu da ndi ve y tudng cua giai thuat phan ldp SVM, chiing ta c^n tim mot sieuphang dl phan tach tap du lieu S gia su nhu tren thlnh 2 ldp ldp C+ va C~

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

Phucrng phap trich chon dac tnmg nay se tao ra mot day so cac dac tnmg giamdan(hinh 3-2) Vdi cimg mot chS thi cac gia tri ldn d dau day tucmg doi on dinh, co thedai dien cho hinh dang khai quat cua chu, con cac gia tri cudi day nhd dan va khong ondinh, thi hien su da dang trong timg chi tidt nho cua chu

3.2.2 May hoc vector h trp SVM

SVM la phuong phap phan lop dua tren ly thuySt hoc thdng ke, duoc d xuit bdiVapnick(1995)

Gia sir cho trade tap S cac dilm x( E Rn, i = 1,2, , I

S = {xt ERn,i = 1,2, ,(}

Mdi diem x^ hoac thupc ldp C+hoac thuoc ldp C~, gan mdi diem xt mot nhan yt,

Ta tinh dupe khoang each tir goc toa dp den H2 14: dx = (1 — b) / II w II

Ta tinh dupe khoang each tir g6c toa dp din H2 14: d2 = (—1 - b) / II w II

Suy ra khoang each phan hoach d giita H^, H2 14: d = \d2 — d2 \ = 2 / || w ||Trong do II w II14 dp 16m cua vector w

Si6u phang toi uu ma S VM can tim se nam giua 2 sieu phang ho trp, chinh vi vaySVM giai quyet van de ph4n lop thong qua khoang each phan hoach nay, duomg phanlop tot nhat chinh la duomg co khoang each phan hoach 16m nhat

Nhu vay de giai quyet bai toan cue dai hoa 16 ta se di tim cue tieu cua ||w||, baitoan nay kho giai quyet vi no lien quan den mot can bac hai Tuy nhien ta co the thay

doi phuomg trinh bod thay the || w 11 vdi - ||w|[2 ma khong phai thay d6i giai phap (cue

tieu goc va dieu chinh phuomg trinh de co dupe cung w va b) Van de nay 14 mot baitoan quy hoach toan phuomg toi uu:

1.

Vb:

Ilinh 3-4: Sieu phang phan cilia bai tap liuiu [24|

Gia sir phuomg trinh sieu phing can tim la wx + b = 0 (tSp du lieu co th6 ph^ntach tuyen tinh hoan toan) trong do w la vector phap tuyen cua sieu phang w 6 Rn, b

la dp lech cua sieu phSng d6i vdi g6c toa dp

Ta co 2 bdt phuong trinh sau:

xt.w >b + l,V^; e C+ (y; = +1)

xt.w <b- l,V*i EC" (y, = -1)

Ket hop 2 bat phuong trinh tren ta co:

dioang cdch phSn hoach

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

SVTH: Nguyen Tan An - DTH09202121

,0,Z^^ II" II "I" ^ s.t

Hiuh 3-5: Phan lop tuyen tinh lift lieu khong tach roi.[l]

Trong trubng hop cac du lieu khong tach rbi, ton tai di6m xt va ndm sai phia sovbi sieu phang ho trp (hinh 3-5), may hoc SVM se xem no la loi, khoang each loi dupebilu di6n bbi zt > 0 (vbi xt ndm diing phia cua sieu phang h trp ciia no thi khoangeach loi tuong ling Z; = 0, con ngupc lai thi zf > 0 la khoang each tir diem xt den sieuphang ho trp tuong ung cua no) Nhu vay viec tim kiem sieu phang toi uu cua giaithuat may hoc SVM thuc hien cung luc 2 muc tieu la cue dai hoa le va cue tieu hoa loi

Ta cb phuong trinh quy hoach toan phuong

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

sao cho

y (w.Xj-^^) >1i = l,2, ,l

- Cue tilu hoa 16i

Bai toan di tim sieu phang bang cue dai hoa le trSn dp dung cho trubng hop SVMphan lop tuyen tinh dtt lieu hoan toan tach rbi nhau Nhung neu du lieu khong tach rdinhau nhu vay viec phan lop nay se phat sinh 16i, chinh vi vay d giai quy^t bai toannay chinh la giai quyet bai toan cue tieu hoa loi cho gi^i thuat phan lop SVM

maxaL(a) = ^ o( - -^ _, aiaiyiy'XiX>

Ta chuydn bai toan tim maxai(a) vd dang tdi uu nhu sau :

SVTH: Nguydn Tin An - DTH09202122

maxa \minWib L(w, b,a) = - \\w\\

Dd tim min cua L(w,b,a) ta lay dao ham cua no theo w va cho bang 0 nhu sau :

dL

-—=0 -w =

ow

dL dbLoai bd w va b ra khdi L(w,b,a) bang each the ^|=i aixiyi, ^|=i aiVi vao ta duac :

a = (aa, a2, , a()T > 0 la mot nhan tu Lagrange

Va dilu kien KKT ddi vdi viec phan ldp SVM se du^e hi^u nhu sau :

a( = 0 => I?; > 0 (mlu nim vh hai phia ddi vdi H-^ va H2),

0 < at < C => /?; ~ 0 (mlu nlm tren hai sieu phlng Ht hoac Hz),

a; = C => R^ < 0 (mau bi nhieu)

Trong trudng hop sau, didu kien KKT bi vi pham :

at < C va Rt > 0

at > 0 vh Rt > 0Chuyen bai toan L(w, b, a) ve bai toan ddi ngau ta co :

Tim hieu ky thuat nhan dang ky ty so viet tay va tmg dung nhap didm tir ddng

Ta chuyen bai toan trdn vd dang bai toan quy hoach toan phvtong co sit dungnhan tit Lagrange, ham Lagrange cho ta giai quydt bai toan tim cue dai ham f(x) vdididu kidn ham g(x) > 0 se duac vidt dudi dang nhu sau:

L(x,X)=f(x)+\g(x)Ndu la cue tidu thi:

Trong do x va X phai thoa dieu kien Kaiush-Kuhn-Tucker (KKT) nhu sau :

g{x) > 0

X>0

^g(x) = 0

Ta co phucmg trinh -||w||2 + c^-=1Zj vdi y (w.Xi — b) + z^ > l,z( > 0 (i =

1,2, , I) viet dudi dang ham Lagrange nhu sau :

^.*; - b) - 1]

23SVTH: Nguyen Tan An - DTH092021

Trong do ^(xj)<b(Xj) la tich vo hudng cua cac vector Xj, Xj duoc anh xa vaokhong gian Rd, do Rd co s6 chi^u rit ldn nen viSc tinh tich vo hudng nay se trd nen ratphuc tap B^ giai quy6t vSn &b nay ldp ham nhan (khong gian Hilbert Schmidt) co th^giup SVM lam viec true tiep trong khong gian d^u vao nhung ngam dinh xu ly dkhong gian trung gian, khong co bat ky thay doi nao can thiSt ve mat giai thuat, vieclam duy nhat la thay the cac tich vo hudng cua hai vector O(Xi)<t>(x;) bdi ham nhanK(x;, Xj), vdi ham nhan nay viec tim khoang each Id cue dai se dugc tinh gian tieptrong khong gian dac trung ma khong can phai xac dinh ro anh xa ^>

Trong do d ldn hon n va d co the la vo cue.

Nhu vay, ham t6i uu L(a) duuc vi6t lai vdi:

Gia sil ta co tap du lieu khong kha tach tuyen tinh trong khong gian Rn thi muctieu ciia bai toan la tim each anh xa chung sang khong gian Rd sao cho trong khonggian nay chiing kha tach tuygn tinh, Rd duqc gpi la khong gian dac trung

Anh xa bien doi:

Hinh 3-7: Phan lop tuyen tinh trong khong

gian trung gian 111 Hinh 3-6: Pban liVp phi tuyen 111

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

i ii mirla2/-i^

1=1 j=i

Vdi ^[=i atyi = 0 va at > 0 (i = 1,2 , I)

Bai toan nay da giai quyet duoc van de phan ldp du lieu khdng tach rdi

3.2.2.2 SVMphituySn

Trong trudng hop tdng quat, thuc te mat phan hoach co the la mat phi tuyen bat

ky (hinh 3-6) Vdi tap du lieu khong kha tach tuyen tinh, co the anh xa chung sang motkhong gian khac vdi so chieu nhieu hon sao cho vdi khong gian mdi nay tap du lieukha tach tuyen tinh

1=1

predict(x) = signi^yiCiiKixyx) + b)

Neu predict(x) >= 0 thi thupc lop C+ ngupc lai neu predict(x)<0 thi thupc ldp C-

3.2.2.5 SVM da ldp

SVM la mdt bai toan phan ldp nhi phan, tuy nhien trong cac fag dung thuc te thi

sd ldp cin phan loai thudng nhifa hon 2 ldp Vi vay dl ap dung SVM vfa cac bai toanphan loai nhiSu ldp co th chuySn cac bai toan nay vS dang 2 ldp Sau day la mot s6chien lupc de SVM phan loai da ldp

- Chien Iu^c mot chong mot (OVO: One-versus-One)

Vdi chi^n lupc nay ta se ti^n hanh xay dung ttag bp phan ldp SVM cho ttog capldp, bp phan ldp nhi phan se dupe huin luyen teen tap con cua tap du lieu, va tap connay chi chua mlu du lieu cua 2 ldp Nhu vay ddi vdi phan loai N ldp thi chiing ta phaixay dung —-—- bp phan ldp Mot du lieu can phan loai se dupe phan loai teen

—^—^ bp phan ldp do, k^t qua du lieu dupe phan vao ldp nao nhi^u nhat thi do chinh

la ldp cua du lieu can phan loai

Uii di^m cua chi^n lupc nay la tim tai nhi^u mat phan each khac nhau cho m5icap ldp Do do, neu mot mau thupc mot ldp bi phan ldp sai thi mau do van con ca hoi

SVTH: Nguyln Tfa An - DTH09202124

Vai ^|=1 a^ = 0 va at > 0 (i = 1,2 , I)

Tir tap du lieu mau thong qua ham tren ta tinh ra dupe nhung x^ tuong fag vdicac at la vector h6 tra (SV) va tinh ra b tren tap SV nay

Khi dua mot du lieu x mm vao dS phan loai, bp phan lop SVM se sir dung tap SV

va b da tim dupe nay vao ham quyet dinh d^ xac dinh xem x thupc lop n^o

Ham quyet dinh :

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

3.2.2.3.Ham nhan

Cac loai ham nhan thong dung :

-Ham nhan tuyen tinh: K (x, y) = x y.

-Ham nhan da thuc: K(x, y) = ((x y) + e)^, d e N,6 e R.Ham nhan dathiic nay co the chuyen tat ca cac mat cong bat d trong khong gian Rnthanh sieu phang trong khong gian dac trung

-Ham nhan Gausse (RBF - Radial Basic Function): K(x,y) =

\\x—vll2^

exp(—) a 6 R Chieu cua khong gian dac trung fag vdi ham nhanGausse la vo han Do do no co the chuyen mot mat cong bat ky trongkhong gian Rn thanh sieu phing trong khong gian dac trung

3.2.2.4.Thuc hienphan loai

Nhu vay, bai toan tim sieu phang toi uu trong khong gian dac trung se dupe giaithong qua bai toan toi uu sau:

: ii

mina 2 2^ 2j ^^ yiK(-Xi" x^

SVTH: Nguyln Tin An - DTH09202125

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

dupe phan lop dung nho vao cac bp phan lop con lai, do do chign lupc nay phan lopkha chinh xac Tuy nhien, de sung dung chien hrpc nay trong bai toan phan N lop thi

can phai co — may phan lop, neu tang N thi so may phan lop se tang len rat

nhanh, dieu nay se lam cho toe dp phan lop giam dang kg [12]

-Chien lirpc mot citing phiin con lai (OVR: One - versus - Rest)

Day la chien lupc don gian nhat cho bai toan phan nhieu lop Vdi N lop thi tignhanh xay dyng N bp phan loai, moi bp phan loai phan loai mot lop Cach xay dyng

nhir sau:

Tign hanh xay dyng bp phan lop tap dB lieu thii i vdi tdt ck cac tap du lieu conlai, luc nay ta danh nhan tap d(J lieu i can phan loai la 1, con cac tap con lai se la -1,tuong ty nhu thg cho ttag tap du lieu ciia tirng lap khac, mi lin nhu vay chiing ta cindanh nhan lai cho tap du lieu phan loai

Uu diem cua chign lupc nay la so bp phan lop it, do do toe dp phan lop nhanhhon Tuy nhign, du so may phan lap it nhung moi Ian huan luyen phan lap thi toan bptap du lieu dgu tham gia huin luyen, do do thdi gian huin luyen tang len dang kg.Nhupc digm chinh cua chign lupc nay la neu mot mlu khi bi phan ldp sai thi se khong

co co hoi dg thyc hien lai, do do dp chinh xac phan ldp cua chign lupc nay khong cao.-Chien ltroc phan cSp

Y tudng cua chign lupc nay dya trgn cau true phan cap, su dung cay nhi phan,nut goc cua cay pMn ldp la mot may phan ldp nhi phSn phan chia toan bp cac ldpthanh hai nhom ldp, sau do tuy dau ra cua may phan ldp nay ma cac nut con tiep tucphan tach cho dgn khi xuong dgn nut la

Chign lupc phan cap co tdc dp nhanh nhit so vdi hai chign lupc trgn nhung nocung co mot nhupc digm ldn: ngu mot mlu x cho trudc bi phan ldp sai ngay nut dautign thi ch^c chdn kgt qua phan ldp se sai cho du co tigp tuc phan ldp xtidng dgn t|nnut la Vi vay chign lupc nay thudng cho dp chinh xac khong 6n dinh b^ng hai chign

-Tich hop cac cong thiic tinh toan trong SVM

-Kha nang phan loai da ldp

-Cho phep lua chpn mo hinh phan loai

-Uoc lupng xac suat

Hinh 3-8: Mang no-ron sinh hoc.

Trong do:

-Cac Soma la than cua na-ron.

-Cac dendrites la cac day manh, dai, gan lien vdi soma, chung truyen du lieu(dudi dang xung dien the) den cho soma xir ly Ben trong soma cac do lieu do

SVTH: Nguyln Tin An - DTH09202126

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

SVM.net cua Matthew Johnson la phien ban dugc chuyen doi tir phien banlibSVM danh cho Java No cung cfip d^y du tinh nang va hieu qua gi6ng nhu phien bang6c nhung cSu true dugc thay d6i cho phu hgp vdi ndn tang Net

- Binh dang tap dir lieu

SVM.net yeu cau tap dtt lieu dua vao hufin luyen hay nhan dang can phai dungtheo 1 cau true dinh sEn Dudi day la cau true cua dd lieu:

label index^.value-^ index2:value2 index3:value3 indexn:valuen

label: la nhan cua dong dtJ lieu

index: la vi tri cua gia tri

value: la gia tri cua dO lieu tai vi tri index

Mot vi du ve each dinh dang du lieu cua 2 mau thuoc lap 0 va 1 de dua vao bophan lop SVM.net

00:191 1:99 2:97 3:44 4:16 5:28 6:16 7:8 8:8 9:4 10:2 11:2 12:1 13:2 14:2 15:1 10:146 1:39 2:67 3:48 4:16 5:24 6:16 7:8 8:8 9:4 10:2 11:2 12:1 13:2 14:2 15:1

3.3 Phan lop voi mang no-ron nhan tao

3.3.1 Mang na-ron nhan tao

3.3.1.1 Tong quan ve mang na-ron nhan tao

Mang na-ron nhan tao (Artificical Neural Networks: ANN) ra ddi xuat phat ttr ytudng mo phong hoat dong cua bo nao ngudi

Mang na-ron nhan tao la su tai tao bang ky thuat nhung chuc nang cua he thankinh con nguai vdi vo s6 cac na-ron dugc lien kSt truyen thong vdi nhau qua mang.Gidng nhu con ngudi, ANN dugc hoc bdi kinh nghiem, luu nhung kinh nghiem do vasir dung trong nhung tinh hudng phu hop

Mang neural dua tren viec mo phong cap thdp he thong na-ron sinh hoc nhamgiiip may tinh cd kha nang hoc tap, nhan dang va phan loai

Sau day la nhung thanh phln chmh trong cau true cua mot na-ron trong bo naocon ngudi:

SVTH: Nguyln Tin An - DTH09202127

Hinh 3-9: Mang no-ron nhan tao.

No-ron nay se hoat dong nhu sau: gia sir cd N inputs, noron se cd N weights(trpng so) tuong dng vdi N dudng truyen inputs Na-ron se lay tong cd trpng so cua tat

ca cac inputs Ndi nhu the cd nghia la no-ron se lay input thu nhat, nhan vdi weighttren dudng input thu nhlt, liy input thu hai nhan vdi weight cua dudng input thu haiv.v , rdi liy tdng cua tit ca cac kit qua thu dupe Dudng truydn nao cd weight cangldn thi tin hieu truydn qua do cang ldn, nhu vay cd thi xem weight la dai lupng tuongduong vdi synapse trong no-ron sinh hoc Cd thi vilt kit qua liy tdng cua no-ron nhu

sau:

N

y= Z y>i*i

Input x, Tdng -> So sSnh v<

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

dupe tdng hop lai Co the xem gan dung su tdng hop ay nhu la mot phep lay tdng

tat ca cac dfl lieu ma ncrron nhan dupe.

-Mot loai day dan tin hieu khac cung gan vdi soma la cac axon Khac vdidendrites, axons co kha nang phat cac xung dien thi, chiing la cac day din tinhieu tu no-ron di cac nai khac Chi khi nao dien thi trong soma vupt qua mot giatri ngudng nao do (threshold) thi axon mdi phat mot xung dien the, con neukhdng thi no d trang thai nghi

-Axon n6i vdi cac dendrites cua cac na-ron khac thong qua nhung m6i n6i dacbiet gpi la synapse Khi dien the cua synapse tang len do cac xung phat ra tir axonthi synapse se nha ra mot so chat hoa hoc (neurotransmitters); cac chat nay mo

"cua" tren dendrites de cho cac ions truyen qua Chinh dong ions nay lam thay doi dien th^ tren dendrites, tao ra cac xung do lieu Ian truyen tdi cac na-ron khac.

> Co the torn tat hoat dong cua mot no-ron nhu sau: no-ron lay tong tat ca cac dien

the vao ma no nhan dupe, va phat ra mot xung dien the neu tong ay Ion hon mot

nguong nao do Cac noron noi vdi nhau d cac synapses Synapse dupe gpi la

manh khi no cho phep truy&i din dl dang tin hieu qua cac no-ron khac Ngupclai, mot synapse yeu se truyen dan tin hieu rat khd khan

Cac synapses dong vai tro rat quan trpng trong su hoc tap Khi chung ta hoc tapthi hoat dong cua cac synapses dupe tang cudng, tao nen nhieu lien ket manh giiia cac

np-ron.

Co the ndi rang ngudi nao hoc cang gidi thi cang cd nhieu synapses va cac

synapses ay cang manh me, hay ndi each khac, thi lien ket giita cac no-ron cang nhieu, cang nhay ben.

Sau day la mo hinh cua mang no-ron nhan tao:

28SVTH: Nguyen Tan An - DTH092021

WS,^WS,2"WS,R w2ilw2i2 w2>Ji

Luu y la chi s6 cua tong bay gid bat d^u tir 0 chu khong phai bang 1 nhu trudc

nua.

3.3.1.2 Kiln tnicmang

- Mang mot tSng

Mang mot tang vdi S no-ron duqc minh hqa trong hinh 3-10 Chu y rang vdi moi

mot dau vao trong so R dau vao se duqc noi vdi timg no-ron va ma tran trong so bay

gid se co S hang

Mot tflng bao gdm ma tran trong so, cac bq cqng, vector ngudng b, ham truyen va vector d^u ra a.

Moi phan tii ciia vector dau vao p duqc noi vdi timg no-ron thong qua ma tran

trong so W Moi no-ron co mot ngudng bt, mot ho cqng, mot ham chuyen / va mot dluraa;.

Ciing vdi nhau, cac dlu ra tao thanh mot vector diu ra a

Thong thudng thi s6 luqng d^u vao ciia ting khac vdi s6 luqng no-ron.(R#S)

Ma tran trong so cho cac phan tir trong vector dau vao W:

Trong do f la ham Heaviside: f duqc gqi la threshold function hay transfer

function cua no-ron, con gia tri (-t) con duqc gqi la bias hay offset cua no-ron.

Nlu chiing ta dua them mot input nua vao, input thu 0, co gia trj luon luon bang

1 va weight luon luon bang bias (-t) thi output cua noron con co th^ viet dudi dang:

\-t

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

Ket qua nay se duqc so sanh vdi threshold t cua ron, neu no ldn hon t thi

no-ron cho output la 1, con neu nhd hem thi output la 0 Ngoai ra ta cung co the trir tong

noi tren cho t, roi so sanh ket qua thu duqc vdi 0, neu ket qua la duong thi no-ron cho

ouput bang 1, neu kit qua am thi output la 0 Dudi dang toan hoc ta co thi viet output

cua noron nhu sau:

Hinh 3-11: Vi du ve mot mo hinh mang no-ron da tang.

M6 hinh mang no-ron 6 hen g6m 3 lop: lop nhap (input), lop in(hidden) va lopxuit (output) M6i nut trong lop nhap nhan gia hi cua mot biin doc lap va chuyin vao

mang.

SVTH: Nguyln Tin An - DTH09202129

Hinli 3-10: Mo hinh mang mot lop.

Cac chi so hang cua cac phan tu trong ma tran W chi ra no-ron dich da ket hopvai trong so do, trong khi chi so cot cho biet dau vao cho trpng so do Vi vay, cac chi

so trong w32 noi rang day la trpng so cua dau vao thii 2 noi vdi no-ron thu 3.

- Mang da tSng

a = f(YVp+b)

Tim hieu ky thuat nhan dang ky tu so viet tay va ling dung nhap di&n tu dpng

d output =

M6 hinh toan cita Perceptron: output =

f dupe gpi la ham kich hoat (activation action) hay ham truyen co the la ham:

tuygntinh, ngudng (Heaviside step), logistic sigmoid (x) = ——, Gauss,

Xet trudng hop perceptron su dung ham kich hoat nguang thi:

Hinh 3-12: Mang no-ron perceptron.

Tim hilu ky thuat nhan dang ky tu so viet tay va ting dung nhap diem tu dpng

Du lieu tu tat ca cac nut trong lap nhap dupe tich hap ta gpi la tong trpng so

-va chuyen ket qua cho cac nut trong lap an Gpi la "an" vi cac nut trong lap nay chi

lien lac vai cac nut trong lap nhap va lop xuat, va chi co ngucri thiet ke mang mdi bietlop nay (ngudi sir dung khong biet lap nay)

Cac nut trong lop xudt nhan cac tin hieu t6ng trpng hoa tir cac nut trong lap an.Moi nut trong lop xuat tuang ung vai mot bien phu thupc

3.3.1.3 Thuat toan hoc

- Thuat toan huan luyen cua mang no-ron mot tang (mang Perceptron)

Perceptron la mang chi co mot lop ron (lop nay co the co mot hay nhieu

na-ron), co cau tnlc nhu sau:

Input Ldp ndron

Hinli 3-13: Mang no-ron MLP.

Huan luyen mang no-ron nhieu tang sir dung thuat toan Ian truyen ngupc gom haiqua trinh: Qua trinh truyen tuyen tinh va qua trinh tuyen ngupc:

Qua trinh truyen tuyen tinh: Du lieu tit ldp nhap qua ldp an va den ldp de xuat

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

-Budc 2: Hoc: vdi moi mau (x,t) trong tap hoc

Tinh y = f(x,w)

Neu y != t thay doi vec-to trong so w vdi: w(mdi) = w(cu) + ^(t-y)x

-Budc 3: Lap lai budc 2 cho t&t ca cac mlu

Vay ta thay qua trinh hoc thuc chit la qua trinh di tim cac trong so w sao cho 16ixay ra la nhd nMt Dieu kien dung trong qua trinh hoc co the la mot trong cac tieu chi,hoac ket hop nhieu tieu chi: lot nho den mire chap nhan dupe hoac sau mot so budc lap

du ldn va mot so tieu chi khac

Phuong trinh v.w = 0 chinh la mdt sieu phang trong khong gian d-chieu nen rorang mang Perceptron co kha nang phan lap tuyen tinh, hay ndi each khac co kha nanggiai bai toan hoi quy tuyen tinh

Tuy nhien Perceptron cung co han chS la khong th^ phan ldp phi tuy^n Chinh vithe nam 1986 Rumelhart va McCelland da cai tiSn Perceptron thanh mang Perceptronnhieu ldp (MultiLayer Perceptron, MLP) hay con gpi la mang Feedforward

- Thuat toan huSn luyen Ian truyfin nguoc cho mang no-ron nhilu t^ng (mangMLP)

Mang MLP la mot mang gdm mot hay nhiSu ldp no-ron Sau day la mot vi dugom hai ldp, moi ldp co 2 no-ron:

Input Ldp 1 Ldp 2

Sau khi hieu chinh trqng so, mau Xs tiep tuc duqc dua vao mang lan thii (1+1) vatigp tpc thuat toan hieu chinh trqng s6 cho dSn khi E < e cho trudc hoac s6 vong lapdat d^n mtic dinh tmac

Vai lien ket giua na-ron vao va na-ron an: Wij(l + 1) = w;-(0

Trong do :

•AlVy =H.Sj(I).Xi

•y.: la he s6 hoc

fi: la hS s6 hocy;-: duqc tilth theo cong thuc (1)

Buac 2: Lan tmyen nguqc sai so:

So sanh cac ph^n tu: cua vec-to &ku ra thuc Ys vdi cac phSn hi tuong ung

cua vec-to dau ra mau Ts de tinh sau lech:

ek = tk-y^ _

T6ng binh phuorng sai s6 cua mang ting vdi mlu hoc Q^, Ts):

i=l

Biu ra tai no-ron k cua lop ra:

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

Qua trinh huan luyen la qua trinh hoc vcri cac tap mau (Xs, Ts),s = 1,N de dieuchinh tap trong s6 lien kt Giai thuat huSn luyen ph6 bi^n d6i vdi cac mang MLP lagiai thuat Ian truyen nguqc sai so Back Propagation

- Budc 1: Lan truyen xuoi dau vao Xs = {xlx^2, , xn] qua mang:

B^u ra tai no-ron j cua lop in: