baocao

TNG HP TING VIT CHT LNG TT Trang

inh ng Lng Lp Cao hc XLTT&TT 2007

1

LI NI U

My tnh ng vai tr quan trng v khng th thiu trong cuc sng hin

i. Ngy nay, hu ht cc lnh vc nh: c kh, kinh t, in t, giao thng lin

lc, ... u c s tham gia ca my tnh. My tnh tr thnh mt cng c hu

hiu ca con ngi trong x l thng tin. Cng vi s pht trin nhanh chng

ca my tnh, cc hnh thc trao i, giao tip thng tin gia con ngi v my

tnh cng tr nn a dng. Hin ti vic trao i thng tin ph bin gia ngi v

my thng qua giao tip bn phm, chut, cm bin, mn hnh, my in, .... Tuy

nhin, mt trong nhng phng php trao i thng tin mi c nh gi cao

v kh gn gi i vi con ngi l giao tip gia ngi v my bng ting

ni. t c yu cu ny i hi s kt hp ca nhiu ngnh nghin cu nh

ngn ng hc, x l ting ni v cc ngnh lin quan,... trong vn tng hp

ting ni l mt trong nhng vn cn nghin cu v s c cp trong lun

vn ny.

Tng hp ting ni c bit n v nghin cu kh rng ri trn th

gii. Nhng kt qu thu c l rt kh quan, iu ny lm tin quan trng

cho s pht trin v ng dng trong qu trnh giao tip ngi my. Trn th gii

c kh nhiu ngn ng c tng hp thnh cng vi cht lng kh tt nh

ting Anh, ting Php, Vit Nam, vn x l ting ni mi c ch trng

v nghin cu trong thi gian gn y, nhng cng thu c mt s kt qu

ng khch l.

Vi mc ch gp phn vo s pht trin ca tng hp ting Vit, k tha

v pht huy nhng nghin cu trc , ti chn ti Tng hp ting Vit

cht lng tt. Vi mong mun c th tng hp c cc t ting Vit vi

cht lng gn ting ni t nhin nht, ti xut phng n thc hin b

tng hp ting Vit cht lng tt trong bao gm c vic xy dng c s d

liu ting Vit sao cho m bo cht lng tng hp tt.

Ni dung bo co c chia lm 5 chng:



2

Chng I: Tng quan. Ni dung chng ny nhm phn tch, nh gi cc

cng trnh nghin cu c ca cc tc gi trong v ngoi nc lin quan n

ti, nhng vn cn tn ti v cc ni dung, vn m ti s tp trung

nghin cu v gii quyt.

Chng II: L thuyt v x l ting ni. Nhng vn c bn nht v cc

lnh vc ca x l ting ni, cc c trng ca tn hiu ting ni v cu trc

c bn ca ng m ting Vit s c trnh by trong chng ny.

Chng III: Tng hp ting ni. Trnh by tng quan v tng hp ting ni,

cc phng php khc nhau trong tng hp ting ni, ng thi a ra nhng

nh gi v hiu qu ca cc phng php .

Chng IV: xut v xy dng b tng hp ting Vit cht lng tt.

Da trn nghin cu l thuyt trong cc chng trc, chng ny s tp

trung nhng ni dung chnh ca ti bao gm: xy dng c s d liu, mt

s xut p dng trong b tng hp ting Vit nhm nng cao cht lng

tng hp.

Chng V: nh gi kt qu v hng pht trin

Mc d rt c gng song bn lun vn chc khng th trnh khi c nhng

thiu st. V vy, rt mong c hi ng v qu Thy, C gp .

Cui cng ti xin gi li cm n chn thnh ti ton th hi ng bo v, lp

KTMT-K50 cc Thy, C gio trong khoa Cng ngh thng tin, c bit l cc

Thy trong b mn K thut my tnh to mi iu tt cho ti trong thi gian

hc tp v nghin cu ti b mn. Ti xin gi li cm n c bit ti TS. Trnh

Vn Loan ngi tn tnh gip , hng dn ti hon thnh lun vn ny.

Nhn y, ti xin gi li cm n ti nh trng, Khoa Cng ngh Thng tin i

hc Nha Trang cng ngi v thn yu ca ti to mi iu kin thun li

cho ti trong sut kha hc ny.

H Ni, ngy 02 thng 10 nm 2009

Thc hin ti

inh ng Lng



3

CHNG 1: KHI QUT V CC NGHIN CU TNG HP

TING VIT

1.1 Tng quan v x l ngn ng ting Vit

Gn y, vn x l ngn ng v x l ting Vit c cc nh khoa hc

hng u trong lnh vc cng ngh thng tin trong nc quan tm. Cc sn

phm tiu biu v x l ting Vit nh: b g ting vit Vietkey, t in Anh-

Vit, Vit-Anh, hay phn mm dch song ng EVTRAN, phn mm nhn dng

ch Vit vnDOC, l nhng sn phm c ngi s dng bit n. Tuy

nhin, cc cng c h tr trong lnh vc giao tip ngi my nh nhn dng v

tng hp ting Vit vi cc kt qu cn hn ch. C rt nhiu l do, nhng l do

c bn l c qu t cc nghin cu c s, nn tng v nu c th thng l nhng

nghin cu ngn hn, n l di dng cc ti tt nghip, thc s trong cc

trng i hc, thiu s k tha v thiu trang thit b. Kt qu, cho ti nay

chng ta vn cha c nhng b c s d liu no l chun v y cho cc vn

lin quan n x l ngn ng ting Vit, m nhng vn ny nc ngoi

c pht trin t rt lu v c cng ng quc t xc nh l khng th

thiu trong x l ngn ng. Hin ti, mt s sn phm c thc hin mi dng

li mc m hnh, th nghim v tin hnh trn nhng tp ng liu nh, cha

y . Hn na, cc n lc ca chng ta cha c lin kt vi nhau, thiu tnh

chia s k tha, hp tc theo mt l trnh c k hoch. Nu hnh dung cc cng

on ca vn x l ngn ng c nh s t A n Z, th hu ht cc sn

phm lm ra cho ngi dng cui u khong t R, S, tr i, m mun c

kt qu tt trong giai on ny th nht thit phi cn ti kt qu ca tt c cc

bc t A n P, Q. Nh vy, hin ti nu chng ta mun c mt sn phm th

phi lm tt c cc cng on t A n P, Q n Z nh th khng ai c th khng

nh chc chn sn phm R, S,, Z lm c l tt.



4

1.2 Cc nghin cu v tng hp ting Vit

trong nc, c th k n nhng tp th c nhng kt qu nghin cu

v tng hp ting Vit nh Vin Cng ngh Thng tin, Khoa Cng ngh Thng

tin v Trung tm nghin cu quc t Thng tin a phng tin, truyn thng v

ng dng (MICA) - i hc Bch khoa H Ni v kt qu ca mt s trng i

hc l nhng ti tt nghip, thc s hay tin s mang tnh cht nghin cu v

tm hiu. Nghin cu v x l ngn ng c theo ui t kh lu bi mt s

tp th nh i hc Bch khoa H Ni, i hc Khoa hc T nhin thnh ph

H Ch Minh, i hc Bch khoa Nng, Trng i hc Cng ngh, Vin

ng dng Cng ngh, Vin Cng ngh Thng tin, Cng ty Lc Vit, v ti

cp Nh nc Nghin cu pht trin cng ngh nhn dng, tng hp v x l

ngn ng ting Vit giai on 2001-2004 trong chng trnh quc gia KC-01.

nc ngoi, c th k ti nhm nghin cu ti Canada ca tin s L Tang

H vi phn mm tng hp ting Vit c tn Vietvoice, v mt s nghin cu

ca cc cn b v nghin cu sinh Vit Nam ti Vin Khoa hc v Cng ngh

Tin tin Nht bn (JAIST).

X l ngn ng ting Vit ni chung v tng hp ting ni ting Vit ni

ring l nhng vn ch c th lm tt c bi chnh ngi Vit chng ta.

Hin nay, c mt s sn phm tng hp ting Vit nh VietVoice, vnVoice,

VieTTS hay VnSpeech do ngi Vit v mt s ngi Vit Nam nc ngoi

lm ra v c nhng kt qu bc u. Tuy nhin, vn nng cao cht lng

tng hp ca cc sn phm cho ngi dng l ci ch cui cng m ta cn

hng ti. Qua nhiu nm nghin cu, tm hiu v tng hp, ng thi mong

mun gp mt phn xy dng h tng hp ting Vit, chng ti mun hng ti

h tng hp ting Vit cht lng tt trong vn cht lng thanh iu c

a ln hng u.



5

CHNG 2: C S L THUYT V X L TING NI

2.1. Qu trnh pht m

Ting ni l mt phng tin trao i thng tin ca con ngi. Ting ni

c to ra t qu trnh t duy ca con ngi v trung khu thn kinh iu khin

h thng pht m lm vic to ra m thanh.

Ting ni c phn bit vi cc m thanh khc bi cc c tnh m hc c

ngun gc t c ch to ting ni. V bn cht, ting ni l s dao ng ca sng

m c mang theo thng tin. Cc dao ng ny to thnh nhng p lc n h

thng thch gic, c h thng thch gic pht hin, phn tch v chuyn kt qu

n trung khu thn kinh. Lc ny ti trung khu thn kinh, thng tin c ti to

li di dng t duy logic m con ngi c th hiu c.

Tn hiu ting ni c to thnh bi chui cc m v lin tip. S sp xp

ca cc m v c chi phi bi cc quy tc ca ngn ng. Vic nghin cu mt

cch chi tit v nhng quy tc ny cng nh nhng kha cnh khc bn trong

ting ni thuc v chuyn ngnh ngn ng. Vic phn loi cc m v ca ting

ni thuc v chuyn ngnh ng m hc. Khi nghin cu cc m hnh ton hc

ca c ch to ting ni, vic nghin cu v cc m v l rt cn thit.

Hnh 2.1 C quan pht m

1. Hc mi 2. Vm ming trn 3. rng 4. Vm ming mm 5. u li 6. Thn li 7. Li g 8. C ming 9. Yt hu 10. Np ng ca thanh qun 11. Dy thanh gi 12. Dy thanh 13. Thanh qun 14. Thc qun 15. Kh qun



6

Khi pht m, khng kh c y t phi qua kh qun, lung khng kh

chuyn ng lm cho dy thanh rung kt hp vi hnh dng ca tuyn m, mi,

li... ng vai tr nh cc b cng hng v cc b lc s to ra cc m thanh

khc nhau. Ngi ta c th m hnh ha ton b qu trnh pht m bi cc m

hnh ton hc khc nhau.

2.2. c tnh m hc ca ting ni

2.2.1. m hu thanh v m v thanh

2.2.1.1. m hu thanh

m hu thanh c to ra t cc dy thanh b cng ng thi, chng rung

ng ch dn, khi khng kh tng ln lm thanh mn m ra v sau thanh

mn xp xung do khng kh chy qua.

Do s cng hng ca dy thanh, sng m to ra c dng tun hon hoc

gn nh tun hon. Ph ca m hu thanh c nhiu thnh phn hi ti gi tr bi

s ca tn s cng hng, cn gi l tn s c bn (pitch).

2.2.1.2. m v thanh

Khi to ra m v thanh dy thanh khng cng hng. m v thanh c hai

loi c bn l m xt v m tc.

m xt (v d nh m s) c to ra khi c s co tht ti vi im trong

tuyn m. Khng kh khi i qua im co tht s chuyn thnh chuyn ng hn

lon to nn kch thch ging nh nhiu ngu nhin. Thng thng im co tht

xy ra gn ming nn s cng hng ca tuyn m nh hng rt t n c tnh

ca m xt c to ra.

m tc (v d nh m p) c to ra khi tuyn m ng ti mt s im lm

cho p sut khng kh tng ln v sau c gii phng t ngt. S gii

phng t ngt ny to ra kch thch nht thi ca tuyn m. S kch thch ny c



7

th xy ra vi s cng hng hoc khng cng hng ca dy thanh tng ng

vi m tc hu thanh hoc v thanh.

2.2.2. m v

Tn hiu ting ni l tn hiu tng t biu din cho thng tin v mt ngn

ng v c m t bi cc m v khc nhau. Nh vy, m v l n v nh nht

ca ngn ng. Tu theo tng ngn ng c th m s lng cc m v nhiu hay t

(thng thng s lng cc m v vo khong di 50). Cc m v c chia

thnh hai loi: nguyn m v ph m.

2.2.3. Nguyn m

Nguyn m l m hu thanh c to ra bng s cng hng ca dy thanh

khi dng kh c thanh mn y ln. Khoang ming c to lp thnh nhiu

hnh dng nht nh to thnh cc nguyn m khc nhau. S lng cc nguyn

m ph thuc vo tng ngn ng nht nh.

2.2.4. Ph m

Ph m c to ra bi cc dng kh hn lon c pht ra gn nhng im

co tht ca ng dn m thanh do cch pht m to thnh. Ph m c c tnh

hu thanh hay v thanh tu thuc vo vic dy thanh c dao ng to nn

cng hng hay khng. Dng khng kh ti ch ng ca vm ming to ra ph

m tc. Ph m xt c pht ra t ch co tht ln nht.

2.2.5. Cc c tnh khc

2.2.5.1. T sut thi gian

Trong khi ni chuyn, khong thi gian ni v khong thi gian ngh xen k

nhau. T l % thi gian ni trn tng s thi gian ni v ngh c gi l t sut

thi gian. Gi tr ny bin i tu thuc vo tc ni v t ta c th phn

loi thnh ni nhanh, ni chm hay ni bnh thng.



8

2.2.5.2. Hm nng lng thi gian ngn

Hm nng lng thi gian ngn ca ting ni c tnh bng cch chia tn

hiu ting ni thnh nhiu khung, mi khung cha N mu. Cc khung ny c

a qua mt ca s c dng hm nh sau:

0

nWnW

Hm nng lng ngn ti mu th m c tnh theo cng thc sau:

1

0

2N

n

m nWmnxE

Thng thng c ba dng ca s c s dng l ca s Hamming,

ca s Hanning v ca s ch nht. Hm nng lng thi gian ngn ca m hu

thanh thng ln hn so vi m v thanh.

2.2.5.3. Tn s c bn

Dng sng ca ting ni gm hai phn: Phn gn ging nhiu (trong bin

bin i ngu nhin) v phn c tnh chu k (trong tn hiu lp li gn nh

tun hon). Phn tn hiu c tnh chu k cha cc thnh phn tn s c dng iu

ha. Tn s thp nht chnh l tn s c bn v cng chnh l tn s dao ng

ca dy thanh.

i vi nhng ngi ni khc nhau, tn s c bn cng khc nhau. Di

y l mt s gi tr tn s c bn tng ng vi gii tnh v tui:

Bng 2.1: Gi tr tn s F0 ph thuc ngi ni

Gi tr tn s c bn Ngi ni

80 200 Hz Nam gii

150 450 Hz Ph n

200 600 Hz Tr em

Vi 0 n N

Vi n N



9

2.2.5.4. Formant

Vi ph ca tn hiu ting ni, mi nh c bin ln nht xt trong mt

khong no (cc i a phng) tng ng vi mt formant. Ngoi tn s,

formant cn c xc nh bi bin v di thng. V mt vt l cc formant

tng ng vi cc tn s cng hng ca tuyn m. Trong x l ting ni v

nht l trong tng hp ting ni, m phng tuyn m ngi ta phi xc nh

c cc tham s formant i vi tng loi m v, do vic nh gi, c

lng cc formant c ngha rt quan trng.

Tn s formant bin i trong mt khong rng ph thuc vo gii tnh ca

ngi ni v ph thuc vo cc dng m v tng ng vi formant . ng

thi, formant cn ph thuc cc m v trc v sau . V cu trc t nhin, tn

s formant c lin h cht ch vi hnh dng v kch thc tuyn m. Thng

thng ph ca tn hiu ting ni c khong 5 formant nhng ch c 3 formant

u tin nh hng quan trng n cc c tnh ca cc m v, cc formant cn

li cng c nh hng song rt t.

Tn s formant c trng cho cc nguyn m bin i tu thuc vo ngi

ni trong iu kin pht m nht nh. Mc d phm vi ca cc tn s formant

tng ng vi mi nguyn m c th trm ln nhau nhng v tr gia cc

formant l khng i v s x dch ca cc formant l song song.

2.3. Biu din tn hiu ting ni

Nh ta bit mt tn hiu cng vi cc c im ring ca n c th c

biu din trn min thi gian hoc min tn s, hoc kt hp thi gian v tn s.

Tn hiu ting ni xt trn min thi gian c th coi l tn hiu t bin i khi ta

ch xt mt khong thi gian ngn (5-100ms), iu c ngha l tn hiu

ting ni c th coi l n nh trong khong thi gian ngn. Tuy nhin, khi xt



10

trong mt khong thi gian di hn (0,5s) th tn hiu ting ni li l khng n

nh hay n thay i theo cc m khc nhau c pht m bi ngi ni.

c th thc hin cc phn tch trn tn hiu ting ni nhm tm ra cc c

trng ring cho cc on tn hiu ng vi cc m khc nhau, trc ht chng ta

cn c cc phng php biu din tn hiu ting ni. Sau y l mt s

phng php thng c dng.

2.3.1. Tn hiu ting ni trn min thi gian

Hnh 2.2 Biu din tn hiu ting ni trn min thi gian

Trn min thi gian tn hiu ting ni c biu din bi th bin ti

cc thi im t khc nhau nh v d cho trn hnh 2.2. Trong t nhin l mt

th lin tc, tuy nhin tn hiu ting ni c x l trong my tnh c s

ho ngha l ri rc c v mt thi gian v tn s.

2.3.2. Tn hiu ting ni trn min tn s

Chng ta bit rng tn hiu ting ni khng ch bao gm mt thnh phn tn

s m gm rt nhiu thnh phn tn s khc nhau, tn s ln nht c th ln ti

hn 10 kHz, mc tham gia ca cc thnh tn s ny cng khc nhau. Dng

biu din tn hiu ting ni trn min thi gian khng cha thng tin phn

tch cc thnh phn tn hiu cc tn s khc nhau, l l do ngi ta cn n

dng biu din tn hiu ting ni trong min tn s, hay cn gi l ph tn hiu.

V d v ph tn hiu ting ni cho trn hnh 2.3.



11

Hnh 2.3 Biu din tn hiu ting ni trn min tn s

2.3.3. Tn hiu ting ni trn min thi gian v tn s kt hp

Trong khi nghin cu ting ni ngi ta lun c gng biu din tn hiu

nhm thu c nhiu thng tin nht t hnh biu din. Mt trong nhng phng

php biu din c dng nhiu nht v l cch biu din tn hiu trn min

kt hp thi gian v tn s. Thc cht ca cch biu din ny l biu din tn

hiu trn min tn s nhng c thc hin vi cc on tn hiu n nh (thi

gian ngn) theo thi gian. Cc gi tr bin c th hin bng mu sc.

Hnh 2.3 l v d v biu din ny.

Hnh 2.4 Biu din tn hiu ting ni trn min kt hp

2.4. M hnh to ting ni



12

Nhm n gin ho vic phn tch v nghin cu b my pht m, ngi ta

chia b my pht m ra lm hai phn c bn: ngun m v h thng p ng.

H thng p ng bao gm thanh mn, tuyn m, mi v mi. Vic m hnh

ho ny s dng hm truyn t trong bin i Z.

i vi cc m hu thanh, ngun m l dng sng tun hon c bit. Dng

sng ny c m phng bi p ng ca b lc thng thp c hai im cc

thc v tn s ct vo khong 100 Hz.

Hnh 2.5 M hnh ho ngun m i vi m hu thanh

Trong , l cc hng s c trng cho ngun m vi



13

Cc on ng c coi l l tng khi:

di mi on nh so vi bc sng m truyn qua.

Cc on cng sao cho s hao tn bn trong do dao ng thnh ng, tnh

dnh v dn nhit khng ng k.

Ngoi ra ta gi thit thm m hnh tuyn m lc ny l tuyn tnh v khng

ni vi thanh mn, hiu ng ca tuyn mi c b qua, ta s c m hnh to

ting ni l tng v vic phn tch m hnh ng m tr nn phc tp hn. Tip

theo chng ta c th thy rng m hnh ny c nhiu tnh cht chung vi mch

lc s nn n c th c biu din bng cu trc mch lc s vi cc tham s

thay i ph hp vi s thay i tham s ca ng m.

S chuyn ng ca khng kh trong mt on ng m c th c m t

bng p sut m thanh v thng lng, l nhng hm ph thuc di ng (x)

v thi gian (t). Trong nhng on ring bit , cc gi tr ca hai hm ny

c coi l t hp tuyn tnh cc gi tr ca chng i vi sng ti v sng phn

x (c k hiu ln lt bng du cng + v du tr -). Sng ti l sng

truyn t thanh mn n mi, trong khi sng phn x li truyn t mi n thanh

mn. Nu on th m chng ta xt c tit din Am th hm thng lng v hm

p sut ca on ny l:

c

xtu

c

xtutxu mmm ,

c

xtu

c

xtu

A

ctxp mm

m

m

.,

y mm uu , l sng ti v sng phn x

c l tc m thanh

l mt khng kh trong on



14

x=0 v tr trung tm ca on

Mi quan h gia sng ti v sng phn x trong nhng on k tip phi

m bo p sut v thng lng lin tc c v thi gian v khng gian ti mi

im trong h thng. Trong hnh 2.7.a ta thy khi sng ti trong mt on gp

phn thay i v tit din (mi ni gia hai on k tip), mt phn ca n

truyn sang on k tip, mt phn kia quay tr li di dng sng phn x.

Hon ton tng t, khi sng phn x gp mi ni, mt phn c chuyn tip

sang on trc , cn phn kia li phn x li di dng sng ti.

Thanh mn Mi

(a)

(b)

Hnh 2.7 Cch biu din l hc v ton hc

a. M hnh l hc gia on ng m v m+1 b. M hnh ton hc ca on ng th m v m+1

m

r1

)( tum

Tr

Tr

Tr

Tr

)(tum

)(tum

)(1

tum

)(1

tum

)( tum

)(1

tum

)(1

tum

m

r1

)(1

tum

)(1

tum

)( tum

)(tum

)(1

tum

)(1

tum

)( tu

m

)(tum

on ng th m,

tit din Am

on ng th m+1,

tit din Am+1



15

Hnh 2.8 M hnh s ca h thng pht m

Tuyn m c coi nh mt chui lin tip cc ng m v c m hnh

ho bi mt chui gm K b cng hng. Khi hm truyn t ca tuyn m

c dng:

K

i

ii zbzb

BzV

1

2

2

1

11

)(

Mi b cng hng s to ra mt formant c c trng bi tn s trung

tm, tnh theo cng thc:

i

ieK

b

bfF

2

11

2cos

2

1

Vi fe l tn s ly mu ca tn hiu ly mu

Cui cng m thanh c pht ra mi, ni c coi nh mt ti m hc.

S tn x ca mi c biu din bi hm truyn t:

11 zCzR

Hm truyn t ca h thng c dng:

zRzVzGzT ..

Nu gi thit mt trong hai im cc ca thanh mn gn bng 1( = -1) ta c:

zAC

zT

Vi

K

i

ii zbzbzzA1

2

2

1

1

1 11

Hay

12

1

11K

i

i zzA

Ngun Ti m hc Tuyn m



16

l hm truyn t ca b lc o. T(z) l hm truyn t ca m hnh ton im

cc. Cc h s ai ca b lc o s l cc tham s quan trng trong phng php

d on tuyn tnh xc nh cc formant ca tuyn m.

Hn ch ca m hnh ny l khng th to ra cc m xt hu thanh v cc

m mi. i vi cc m mi m hnh trn c ci tin bng cch thm vo

phn c trng cho mi t song song vi m hnh. Lc hm truyn t ca

h thng mi l:

zAzA

zAzA

zAzA 21

1221

2

2

1

1

H thng trn khng cn l h thng ton im cc m n cn xut hin cc

im khng trong mt phng Z. Vic xut hin cc im khng ny s gy kh

khn cho phng php tin on tuyn tnh, c p dng cho cc h thng ton

im cc. Song ngi ta khc phc c kh khn trn bng cch thay mt

im khng bng hai im cc theo phng php gim bc gn ng. Cng thc

gim bc nh sau: ...1

11

221

1

zzz

Tn hiu ting ni khng phi l tn hiu dng, do m hnh phi c

xy dng mt cch lin tc, ngha l cc tham s ca m hnh phi bin thin

theo thi gian. S bin thin ny rt chm nn cc tham s c th coi nh khng

i trong khong thi gian m tn hiu c coi l dng: 20 ms.

Di y l mt v d m hnh ton im cc c dng nhiu trong

nghin cu ting ni:

Hnh 2.9 M hnh ton im cc

Lc thng

thp G(z)

Tuyn m

G(z)

Ti bc x

G(z) P



17

Trong :

)1)(1()(

11

zz

AzG

,

)1()( 1 zCzR ,

v )1(

)(2

2

1

1

1

zbzb

BzV

k

K

k

k

Ti cc v tr , v trn hnh 2.9 tng ng vi xung n v, tn hiu ngun

v tn hiu ting ni.

2.5. X l tn hiu ting ni

Da trn c s la chn cc cch biu din tn hiu v phng php x l,

c rt nhiu cc ng dng quan trng c trin khai. Hnh 2.10 ch ra mt

s ng dng trong lnh vc x l ting ni.

ng dng x

l ting ni

Lu tr v

truyn s liu

Tng hp ting

ni

nh danh v

xc nhn

ngi ni

Nhn dng

ting ni

Tng cng

cht lng

ting ni

Hnh 2.10 Mt s ng dng x l ting ni

Trong cc ng dng ny c 2 ng dng quan trng nht l: Tng hp ting

ni v x l ting ni.



18

2.5.1. Tng hp ting ni

Tng hp ting ni l to ting ni xut pht t biu din ng m ca li

ni. Cc phng php tng hp ting ni hin nay c chia thnh hai nhm:

tng hp ting ni trc tip v tng hp ting ni da trn m hnh.

2.5.1.1. Tng hp trc tip

y l phng php tng hp da trn cc n v m c ghi m trc

tip t ting ni. Trong n v m c th l mt phn ca t, t, nhm t hoc

cu. Qu trnh tng hp theo phng php ny c thc hin bng cch ghp

cc n v m li to nn t, cu. i vi phng php tng hp trc tip, qu

trnh phn loi da theo n v ghi m dng ghp.

2.5.1.2. Tng hp da trn m hnh

i vi phng php ny, c ba phng php tng hp ph bin l: tng

hp bng m phng b my pht m, tng hp da vo formant v tng hp

bng phng php tin on tuyn tnh (LPC).

2.5.2. Nhn dng ting ni

Nhn dng ting ni l lnh vc nghin cu vi mc ch to ra c mt

thit b, my mc hoc phn mm c kh nng nhn bit mt cch chnh xc

ting ni ca con ngi. Trong nhn dng ting ni cn c mt hng c quan

tm nghin cu l nhn dng ging ni.

2.5.2.1. Nhn dng ng ngha

Thng thng iu khin cc thit b my mc ngi ta thng s dng

cch giao tip thng qua s vo ra c kh. Khi p dng ting ni vo giao tip,

li ch ca n c th d dng nhn thy: l tnh tin li, d s dng, tc

giao tip cao. c th s dng ting ni nh mt cng c giao tip th h thng



19

cn c kh nng nhn dng ting ni v ng ngha. Nhn dng ng ngha bao

gm nhn dng t v nhn dng cu.

2.5.2.2. Nhn dng ngi ni

Trong th gii ngy nay tn ti nhiu h thng yu cu an ton bo mt

cao. T ny sinh ra yu cu phi nhn dng c ngi ni bng nhng c

im ring bit m khng ai c th sao chp c. Bn cnh cc cch thc nhn

dng qua ch k, nh chn dung, ch vit, ..., ngy nay ngi ta cn dng ting

ni nhn dng bi v ting ni c nhng c tnh ring bit vi tng ngi.

Ti mt s cng ty xut hin nhng h thng kim tra ngi qua ca bng

nhn dng ting ni hoc nhn dng mi ngi qua th nhn dng m nhng

thng tin lu tr trn th chnh l c im v ting ni ca ngi .

Nguyn tc ca nhn dng ngi ni l s dng nhng t kho c xc

nh t trc m nhng t kho ny c trng cho tng ngi mt. C hai yu t

khng nh s khc nhau trong ting ni ca mi ngi:

Cc c tnh c quan pht m khc nhau nh: di ca tuyn m, tn s

cng hng ca dy thanh, cc tn s formant, di thng, s bin i ca

ng bao ph,... l tp hp nhng c tnh c lin quan n tnh c

lp ca ni dung m v ca t ng.

S khc nhau trong cch pht m ca tng ngi: tc v chiu di t

lun lun khc nhau.

Trong tt c cc c tnh trn ng bao ph v tn s c bn l hai c tnh

quan trng nht. ng bao ph c miu t bng nhng gi tr trung bnh ca

cc b lc thng di, ca cc tn s formant, ca cc h s tin on tuyn tnh,

ca h s cepstre v cc tham s khc.



20

2.6. Mt s c im ng m ting Vit

Ting Vit l ngn ng n m tit v c thanh iu. Vi ting Vit, cc t

khng bin i hnh thi, khng bin i ui t biu th cc phm tr ng

php. Cu to khng dng ph t (tin t, trung t v hu t) v dng rt t hnh

v. Ting Vit c ti a 2 vn ting to thnh cc hnh v. Ting Vit l ngn

ng phn tch.

m ting Vit dng y nht c 5 thnh phn: m u, m m, m

chnh, m cui v thanh iu, tr ph m u phn cn li ca m tit c gi

l vn.

m v t hp nn cc hnh v, do hnh v s c tch ra thnh cc m v.

Ranh gii ca m tit v hnh v trong ting Vit l trng nhau. Mi m tit l

mt hnh v. T vng ca ting Vit phn ln c cu to t mt hoc hai hnh

v, c tnh n tit, song tit, mt s l t a tit.

2.7. Cu trc m tit ting Vit

Da vo s pht trin ca ting Vit hin i, h thng cc m v c bn ca

ting Vit gm 14 nguyn m v 22 ph m. dng y , mi m tit ting

Vit gm 5 thnh phn:

Bng 2.2: Cu trc m tit ting Vit

m u

Thanh iu

Vn

m m m chnh m cui

Th d, m tit ton c phn tch thnh cc m: m u /t/, m m /o/,

m chnh /a/, m cui /n/, v thanh sc.



21

2.7.1. H thng m u

Ting Vit c 22 ph m u nh trong Bng 2.

Bng 2.3: H thng m u ting Vit

1 b 12 nh

2 c/k/q 13 ng/ngh

3 ch 14 p

4 d/gi 15 ph

5 16 r

6 g/gh 17 s

7 h 18 t

8 kh 19 th

9 l 20 tr

10 m 21 v

11 n 22 x

2.7.2. H thng m m

m m c chc nng lm trm ho m sc ca m tit y chnh l cc

bn nguyn m. Trong ting Vit c hai bn nguyn m o/u v i/y

2.7.3. H thng m chnh

Ting Vit c 16 nguyn m c chia thnh 14 nhm nh trong Bng 2.4



22

Bng 2.4: H thng m chnh ting Vit

1 a 8

2 9

3 10 u

4 e 11

5 12 ua/u

6 i/y 13 a/

7 o 14 ia/i/ya/y

2.7.4. H thng m cui v thanh iu

Ngoi m cui /zero/, ting Vit cn c 8 m cui c ni dung tch cc,

trong c 6 ph m v hai bn nguyn m nh trong Bng 2.5

Bng 2.5: H thng m cui ting Vit

1 2 3 4 5 6 7 8

m n ng/nh p t c/ch i/y o/u

Ting Vit c 6 thanh iu: thanh ngang, sc, huyn, hi, nng v ng.



23

CHNG 3: CC PHNG PHP TNG HP TING NI

3.1. Dn nhp

Trong vi thp nin gn y, cc b tng hp ting ni cho cc ngn ng trn

th gii c cht lng ngy cng cao. Tuy nhin, cc phng php ph bin bin

hin nay mi ch t n mc ph hp cho mt vi ng dng v ph thuc vo

ngn ng c th cn tng hp. Tng hp ting ni t vn bn(text-to-speech,

TTS) thuc lnh vc x l ngn ng t nhin v chng c mc tiu ngc vi

mc tiu ca nhn dng ting ni. Kin trc ca mt h thng TTS ging nh

kin trc c ch ca con ngi, bao gm khi l ngn ng t nhin (gm b

tin x l nhm t chc cc cu thnh danh sch, b phn tch hnh thi, b phn

tch ng cnh, b phn tch cu c php, ngn iu, ), c kh nng sinh ra

phin m ph hp vi cch pht m ca qu trnh c vn bn cng vi ng

iu, ngn iu, v khi x l tn hiu s, khi ny chuyn thng tin tng trng

nhn c thnh ting ni. Khi hai khi x l ngn ng t nhin v x l tn

hiu s c nh ngha r rng, vic nghin cu v hai qu trnh c th c

thc hin ring r, c lp vi nhau.

3.2. Cc phng php tng hp ting ni

Hin nay c mt s phng php tng hp ting ni c s dng ph bin.

Tuy nhin, mi phng php li c nhng u im v nhc im khc nhau. V

vy, trong phn ny s gii thiu c th tng phng php.

3.2.1. Phng php m phng h thng pht m.

Phng php m phng h thng pht m (articulatory synthesis) c gng

m phng h thng pht m ca con ngi mt cch hon ho nht, do c th

t c cht lng cao trong tng hp ting ni. Nhng cng chnh iu m

phng php ny kh c th thc hin c, v vic m phng h thng pht m

ca con ngi rt kh thc hin.



24

Sau khi phng php tng hp Formant ra i th phng php m phng

h thng pht m t khi c s dng trong cc h thng. Nhng t khi c s

xut hin ca my tnh th n li c pht trin.

3.2.2. Phng php tng hp Formant.

Phng php tng hp formant (formant synthesis) yu cu phi tng hp

c ti thiu 3 formant hiu c ting ni, v c c ting ni cht

lng cao th cn ti 5 formant. Ting ni c to ra t cc b tng hp

formant vi thnh phn chnh l cc b cng hng. Tu theo cch b tr cc b

cng hng m ta c b tng hp formant l ni tip hay song song.

a. B tng hp formant ni tip

B tng hp formant ni tip l mt b tng hp formant c cc tng ni

tip, u ra ca b cng hng ny l u vo ca b cng hng kia.

Hnh 3.1 Cu trc c bn ca mt b tng hp formant ni tip

b. B tng hp formant song song

B tng hp formant song song bao gm cc b cng hng mc song

song. u ra l kt hp ca tn hiu ngun v tt c cc formant. Cu trc song

song cn nhiu thng tin iu khin hn.

Tng hp formant l mt phng php tng hp cho cht lng chp nhn

c nhng nu yu cu cht lng cao th phng php ny cha p ng

c.

Kch thch

H s

Ting ni



25

Hnh 3.2 Cu trc c bn ca mt b tng hp formant song song

3.2.3. Phng php LPC

Phng php tin on tuyn tnh LPC l phng php rt ph bin cho h

thng m ha ting ni. Tuy nhin, n cng c s dng tng hp ting ni.

Thc t, tt c cc b tng hp ting ni u tin c thc hin da trn b m

ha ting ni.

C s ca phng php d on tuyn tnh l mu y(n) c th c ly xp

x hoc d on t p mu hu hn trc sao cho sai s e(n) nh nht. Nh

vy:

p

k

knykaneny1

)()( (3.1)

p

k

knykany1

~ (3.2)

p

k

knykanynynyne1

~ (3.3)

Vi (n) l gi tr d on, p l th t d on tuyn tnh, a(k) l h s d

on tuyn tnh c tm bng cch ly min tng bnh phng ca cc khung li.

Kch thch Ting ni



26

Tn hiu kch thch c ly xp x bng mt dy cc tn hiu ting ni v

nhiu ngu nhin. Tn hiu ngun c cho qua b lc s vi h s a(k).

Hnh 3.3 Cu trc c bn ca b tng hp LPC

3.2.4. Phng php ghp ni.

Tng hp bng cch ghp ni cc m c tng hp t cc li ni t nhin

c thu t trc c l l cch d nht sn sinh li ni. Phng php tng

hp ghp ni cho cht lng cao v tng i t nhin. Phng php ny rt ph

hp vi cc h thng pht thanh v cc h thng thng tin. Tuy nhin phng

php ny thng ch p dng cho mt ging v phi s dng nhiu b nh hn

cc phng php khc do s lng t vng rt ln. khc phc nhc im

ny ngi ta xy dng cc phng php tng hp ghp ni t nhng n v nh

nh m v, m tit, n v m (m v kp). Ngoi cc n v m, chng ta cn s

dng triphone, tetraphone hay syllable, demisyllable, nhng ch yu vn l cc

n v m, c thu t ting ni t nhin. Cc n v m c ct ra t tn hiu

ri sau c tng hp li theo yu cu da trn mt thut ton ghp ni.

Phng php ny c mt s khc bit so vi cc phng php khc:

Xut hin s bin dng ca ting ni tng hp do tnh khng lin tc ca

vic ghp ni cc n v m vi nhau. V vy phi s dng bin php lm

trn tn hiu.

B nh yu cu cao, nht l khi cc n v kt ni di nh l cc m v hay

cc t.

To xung

B lc s

bc p

To tp m

F0 A

a1 a2 ap



27

Su tm v gn nhn d liu ting ni cn nhiu thi gian v cng sc. V

l thuyt tt c cc mu cn phi c lu tr. S lng v cht lng cc

mu lu tr l mt vn cn gii quyt khi tin hnh lu tr.

Hin nay phng php ny ang c s dng rng ri trn th gii v ngy

cng cho cht lng tt hn nh s tr gip ca my tnh.

Phn tip theo s gii thiu v mt phng php tng hp ghp ni da trn

gii thut PSOLA c p dng ph bin cho tn hiu ting ni.

a. Phng php tng hp PSOLA

PSOLA (Pitch Synchronous Overlap Add) l phng php tng hp da

trn s phn tch mt tn hiu thnh mt chui cc tn hiu thnh phn. Khi cng

xp chng (overlap-add) cc tn hiu thnh phn ta c th khi phc li tn hiu

ban u.

PSOLA thao tc trc tip vi tn hiu dng sng, khng dng bt c loi m

hnh no nn khng lm mt thng tin ca tn hiu. PSOLA cho php iu khin

c lp tn s c bn, chu k c bn v cc formant ca tn hiu. u im chnh

ca phng php PSOLA l gi nguyn ng bao ph khi thay i tn s c

bn (pitch shifting). Phng php ny cho php bin i tn hiu ngay trn min

thi gian nn chi ph tnh ton rt thp. PSOLA c dng rt ph bin vi tn

hiu ting ni.

b. Cc phin bn ca PSOLA

Da trn PSOLA, ngi ta a ra nhiu phin bn khc nhau, di y

l cc phin bn chnh:

TD-PSOLA

Phng php TD-PSOLA (Time Domain- Pitch Synchronous Overlap Add)

l phin bn min thi gian ca PSOLA. Phng php ny thao tc vi tn hiu



28

trn min thi gian nn c s dng nhiu v hiu qu trong tnh ton ca n.

Phng php ny s c trnh by chi tit trong chng tip theo.

FD-PSOLA

Phng php tng hp FD-PSOLA (Frequency Domain- Pitch Synchronous

Overlap Add) l phng php bao gm cc bc ging nh TD-PSOLA nhng

thao tc trn min tn s. Phng php ny c chi ph tnh ton cao hn TD-

PSOLA. i vi mi trng hp ring bit th mi phng php s cho hiu qu

khc nhau, nn phi da vo tng hon cnh chn phng php thch hp.

LP-PSOLA

Ngoi cc phng php trn min thi gian, min tn s, cn c mt

phng php gi l phng php d on tuyn tnh (Linear Prediction - Pitch

Synchronous Overlap Add). Phng php d on tuyn tnh c thit k

m ho ting ni nhng phng php ny cng c th dng cho tng hp.

3.3. M hnh tng hp ting ni t vn bn.

Mt nhu cu rt quan trng trong lnh vc tng hp ting ni l tng hp

ting ni t vn bn (Text To Speech TTS). Qu trnh ny c chia lm hai

mc x l:

High Level Synthesis: Tng hp mc cao

Low Level Synthesis: Tng hp mc thp

Hnh 3.4 M hnh tng hp ting ni

Ting ni Tng hp

mc cao

Tng hp

mc thp

Vn bn

(Text)



29

3.3.1. Tng hp mc cao.

Tng hp mc cao l giai on u ca qu trnh tng hp, giai on

chuyn i cc vn bn thnh cc n v ting ni (v d nh n v m). Vn

bn c nhp hoc sao chp vo, sau qua tng hp mc thp s thnh ting

ni.

Tng hp mc cao gm 3 bc:

X l trc vn bn vi cc ch s, cc k t c bit, ch vit tt, v

nhng t vit tt c ghp bng cc ch u ca cc t y .

Phn tch cch pht m ca t, k c t ng m khc ngha v cc tn

ring.

Phn tch ng iu ca ting ni.

Sau khi tng hp mc cao, thng tin c cung cp cho h thng mc thp

iu khin. Chng hn, vi b tng hp formant th cn cc thng tin nh tn

s c bn, tn s formant, khong thi gian, v bin ca mi on m thanh.

a. X l vn bn

Nhim v u tin ca tt c cc h thng TTS l chuyn i d liu (mu)

v dng thch hp cho mt b tng hp. Trong giai on ny tt c cc c tnh

nh ch ci, ch s, ch vit tt,... phi c chuyn i theo mt khun dng r

rng, y . x l vn bn, ngi ta dng nhng bng i chiu mt - mt

n gin. Trong mt s trng hp cn cn thm thng tin b sung (v d nhng

t gn ngha, nhng k hiu,...). iu ny c th dn n c s d liu kh ln

v tp lut phc tp, s l nhng vn cn gii quyt khi thc hin vi cc

h thng thi gian thc.

V d:



30

Vn bn u vo c th cha cc t vit tt phi c hiu nh nhau trong

tt c cc hon cnh. Nhng s chuyn i t vit tt khng phi lc no

cng da trn cch vit tt m phi da trn c mt cm vit tt (V d: tip

u ng M trong ng cnh no c hiu mega, nhng vit MTV khng

th chuyn thnh megaTV).

Tng t nh vy, vic chuyn i ch s cng khng n gin. Ch s

c s dng vi nhiu vai tr nh l s, l ngy thng, gi tr o c, v

trong nhng biu thc ton hc. Nhng s nm gia 1100 v 2002 thng

thng c chuyn i thnh nm. 1/1/1111 ch s trong mu trn thng

c chuyn i thnh ngy/thng/nm. Nhng 2/5 th tht kh bi v n c

th va l ngy/thng va c th l mt phn s.

b. Phn tch cch pht m

Vi cc ngn ng trn th gii m vic pht m khng hon ton tun theo

quy tc (v d nh ting Anh) th pht m ng cc t l mt vn kh trong

tng hp ting ni. c bit vi ng dng in thoi th hu ht cc t u l tn

hoc l a ch cc ng ph v c ng nhng tn ny l iu khng d

dng. Mt phng php gii quyt l c th lu vo mt bng pht m c bit,

nhng s lng s rt ln. Do , phng php trn khng hiu qu. Lc ny

vic to ra cc lut c bn xy dng nn t in cc t vi cc lut chuyn t

sang m v (letter-to-phoneme) s hp l hn. Cch tip cn ny cng ph hp

vi pht m bnh thng. Khi phn tch, mt t c th c chia thnh cc phn

c lp bao gm tin t, gc t, ph t.

c. Ngn iu



31

Hnh 3.5 S ph thuc ca ngn iu vo cc yu t

Xc nh ng c ng iu, trng m v khong thi gian t vn bn vit

c l l nhng vn kh khn nht trong nhng nm ti. Cc c tnh ny c

gi l ngn iu hoc nhng c tnh siu on v c th c xem xt nh giai

iu, nhp iu v s nhn mnh ca ting ni mc cm gic. Ng iu c

ngha l s thay i ca tn s c bn trong thi gian ni. Ngn iu ca ting

ni lin tc ph thuc vo nhiu yu t nh ngha ca cc cu, c trng v cm

xc ca ngi ni. Ngn iu ph thuc c m t trn hnh 3.5.

3.3.2. Tng hp mc thp.

Tng hp mc thp l qu trnh kt hp cc on tn hiu (v d nh n v

m). Cc on tn hiu ny c phn tch, x l qua mc cao (x l vn bn,

ng iu).

i vi phng php tng hp bng cch m phng h thng pht m ca

con ngi th s chn la d liu v thc thi cc lut l rt phc tp. Lc ny, s

c mt ca my tnh tr gip mt phn ng k.

Ngn iu

Cm gic

Tc gin Hnh phc Bun b

Ngha ca cu

Bnh thng Cu mnh lnh Cu hi

c trng ngi ni

Gii tnh tui

o Tn s c bn o Khong thi gian o nhn mnh



32

Vi tng hp formant th tp lut iu khin tn s c bn, bin v

c trng ca tn hiu ngun li rt ln. V th cng lm mt i tnh t nhin vn

c, c bit m mi c xem l mt vn ln i vi tng hp formant.

Cn vi tng hp ghp ni th vic thu thp cc mu tn hiu v gn nhn

mt rt nhiu thi gian, v c th lm cho c s d liu rt ln. Tuy nhin s

lng d liu c th gim xung ng k nu s dng nhng phng php nn

d liu thch hp. Bn cnh , s khng ng b cc im ghp ni cng c th

lm tn hiu tng hp b mo. i vi nhng n v ghp ni di nh t hoc m

v th hiu qu kt hp l mt vn , ngoi ra b nh h thng cng l mt kh

khn cn gii quyt.

3.4. So snh cc phng php tng hp ting ni.

Sau khi gii thiu nhng c im c bn nht ca cc phng php tng

hp ting ni ta c th rt ra mt s nhn xt v cc phng php ny. Cc nhn

xt ny nhm mc ch a ra nh gi v ba phng php da trn cht lng

ting ni tng hp, chi ph tnh ton v kch thc d liu.

V cht lng ca ting ni tng hp: Trong ba phng php ni trn th

phng php m phng b my pht m v nguyn tc s cho cht lng tt

nht. t c iu ny th vn quan trng l lm sao m phng chnh

xc b my pht m ca con ngi. Cng vic ny hon ton khng n

gin, mc d c s tr gip ca my tnh nhng do cu trc phc tp ca

b my pht m nn chi ph tnh ton s rt ln. Trong hai phng php cn

li th thc t cho thy phng php ghp ni thng cho cht lng tt

hn.

V hiu qu tnh ton: R rng l phng php m phng b my pht m

i hi chi ph tnh ton ln nht v phi m phng mt cch chnh xc nht



33

b my pht m phc tp ca con ngi. Hai phng php cn li c chi

ph tnh ton thp hn do c im cc thut ton c s dng.

V kch thc d liu: Phng php ghp ni c kch thc d liu ln nht

do s lng t vng l rt ln. Hai phng php cn li do khng phi lu

tr cc mu nn c kch thc d liu nh hn.

Qua nhng nhn xt trn th kh khn ln nht ca phng php m phng

b my pht m l lm sao m phng chnh xc b my pht m ca con

ngi. Vi phng php tng hp bng formant th vn cn gii quyt l cht

lng ting ni tng hp. Cn vi phng php tng hp ghp ni th c u

im l chi ph tnh ton khng cao v cht lng kh tt, kh khn ln nht l

gim kch thc d liu. Kh khn ny, nh trnh by, c th khc phc bng

cch tng hp ting ni t nhng n v nh hn t.

Vi mc ch nghin cu vic tng hp ting Vit v da trn nhng c

im ca cc phng php tng hp, trong lun vn ny chng ti s s dng

phng php tng hp bng ghp ni cho ting Vit v mt s gii php nhm

nng cao cht lng ting Vit tng hp, trong c s dng kin thc lin quan

n thut ton TD-PSOLA v kin thc tng hp thng qua vic m phng b

my pht m (ngun m v tuyn m).

3.5. Thut gii PSOLA trong tng hp ting ni

PSOLA l gii thut dng cho phng php ghp ni. u tin ting ni

c phn tch thnh cc tn hiu thnh phn, sau , khi cng xp chng cc

thnh phn ny ta s c tn hiu ting ni tng hp. Phng php ny thao tc

trc tip vi tn hiu trn min thi gian nn c chi ph tnh ton thp. Ngi ta

ko dn thi gian trong tn hiu tng hp bng cch lp li cc on tn hiu

thnh phn.

PSOLA c th hiu nh sau:



34

Tng hp tn hiu t cc thnh phn, trong mi thnh phn c mt tn s

c bn.

Tng hp da trn m hnh ngun-lc (source-filter).

Vi phng php ny tn hiu phi iu ho (harmonic) v phi thch hp

cho vic phn tch thnh cc tn hiu thnh phn khi s dng ca s, iu ny c

ngha l nng lng ca tn hiu phi tp trung xung quanh mt khong thi gian

no trong mi chu k.

3.5.1. Phn tch PSOLA

Phn tch PSOLA bao gm vic phn tch mt tn hiu )(ts thnh cc tn

hiu thnh phn )(tsi bng cch s dng ca s )(th :

)()()( tsmthts ii (3.4)

trong im c gi l cc im mc (markers) phi tho mn cc iu kin sau:

1 ii mm phi gn vi chu k c bn.

Phi gn vi im c bin cc i (maxima energy). iu kin ny

c a ra trnh lm hng tn hiu khi ly ca s.

Sau khi tm c chu k c bn )(0 tT v hm nng lng )(te , cc im

mc im s c xc nh theo hai bc sau:

Bc 1: Tm cc i a phng ca hm nng lng.

V cc im mc phi gn cc im c nng lng cc i nn bc u

tin l tm cc cc i ny. Xt vector ,...,...,, ,1,0, ilill , trong

11,, 0 iilil T . Xung quanh thi im il , xt khong thi gian

1,

1

,,

0,

0 iil

iilil

TTI , y c gi l m rng (extent). Trong mi



35

khong ilI , gi thi im c nng lng ln nht l ilt , . Vi vector L , tnh tng

gi tr nng lng ti cc thi im ilt , : i

ill te )( , . Cui cng, chn ra b

ilit

,' m ti l t cc i.

Hnh 3.6 Xc nh cc i a phng ca hm nng lng

Bc 2: Ti u tnh tun hon v nng lng cc i.

Hai tiu chun ny phi c ti u ng thi v cc im mc im va phi

ng b vi tn s c bn va phi gn vi cc im c nng lng cc i. C

th dng gii thut bnh phng nh nht ti u:

Gi im l cc im mc phi tm, i l gi tr va tm c trong bc 1, iT 0 l

chu k c bn ng vi i . Dng gii thut bnh phng nh nht tm im sao

cho 11 0 iii Tmm v iim . Hm cc tiu phi tm s l:

i

iiiii mTmm22

11 )()0)(( (3.5)

t TNNi mmmmmm ,,...,...,, 110 , khi m c xc inh nh sau:



36

NN

NNN

T

TT

TT

T

Mm

00

00

00

00

1

112

110

00

1 (3.6)

vi M l mt ma trn tam gic vi ng cho chnh c dng

12...21 , tam gic trn v di c dng 11...11 .

3.5.2. Tng hp PSOLA

Tng hp PSOLA c thc hin bng cch cng xp chng cc tn hiu

thnh phn )(tsi c sp xp theo cc thi im jm

j

jj

iij

mtsts

mtsts

)()(

)()(

(3.7)

y im l cc im mc gn nht vi tn hiu vo.

Hnh 3.7 Cng xp chng cc on tn hiu



37

Chu k c bn c iu chnh t )(0 tT ti )(tT bng cch thay i khong

cch gia cc on tn hiu lin tip )(1 tTmm jj . Vi PSOLA vic co dn

trn min thi gian c thc hin bng cch lp li cc on tn hiu.

Tuy nhin, khi thi gian c ko gin nhiu bng cch lp li cc tn hiu

thnh phn c th lm cho tn hiu tng hp khng lin tc. Gii thut TD

PSOLA (Time Domain PSOLA) c trnh by phn tip theo s khc phc

nhc im ny. Hin nay TD-PSOLA cn c m rng s dng cho cc

phng php tng hp ghp ni khc, bi v n l phng php tng hp cht

lng cao v chy tt c nhng my tnh tc thp (tng hp thi gian thc

c th c thc hin vi b vi x l Intel 386).

3.5.3. Gii thut PSOLA

Gi s rng s(n) l tn hiu tun hon , ns~ l tn hiu s(n) sau khi thay

i tn s bng cch ly tng ca cc khung OLA ca si(n), w(n) l ca s. S

thay i chu k tn s gc T0 ti chu k tn s T to ra s thay i ca

nsnsi

~ , :

0iTnwnsnsi (3.8)

i

i TTinsns 0~

(3.9)

Nu TT0 th ta phi lm hi ho li si(n) vi tn s c bn l T

1:

Nu ii Sns

th

i

iT

iST

ns 22~

Cng thc trn rt hiu qu khi mun thay i tn s ca tn hiu tun hon.

Nu T=T0 v ca s phn tch hp, tn hiu tng hp gn nh trng vi tn

hiu gc



38

i

nKsnwnsiTnwnsns ~ (3.10)

Trong trng hp c bit vi ca s tam gic th kch thc ca ca s c

chn bng 2 ln chu k c bn, khi du gn ng ca biu thc trn s tnh

tin ti du bng vi K=1.

Hnh 3.8 Qu trnh lm thay i tn s ca tn hiu



39

CHNG 4: XUT V XY DNG B TNG HP

TING VIT CHT LNG TT

4.1. xut phng n xy dng b tng hp ting Vit cht lng tt

Nh phn tch chi tit trong cc chng trc v nhng u im, nhc

im ca cc phng php tng hp v nhng mc tiu ra ca ti, chng

ny s tp trung trnh by xut nhm nng cao cht lng ca b tng hp

ting Vit trn c s tin hnh xy dng c s d liu nhm m bo cht

lng ca ting ni tng hp.

Ting Vit tng hp cht lng tt, theo chng ti phi l ting ni ting

Vit gn ging vi ting ni t nhin. Ni cch khc, cc tham s ca tn hiu

ting ni c tng hp l xp x vi cc tham s tn hiu ca ting ni t nhin.

y chnh l tng xuyn sut trong qu trnh thc hin v trin khai ti.

Vi cc yu cu ra v nhng phn tch trn, xy dng b tng

hp ting Vit cht lng tt cn thc hin cc cng vic sau:

Xy dng c s d liu m bo tng hp ting Vit cht lng tt.

X l v phn tch vn bn ting Vit.

Thc hin tng hp ting Vit bng phng php ghp ni v xut mt

s gii php nhm nng cao cht lng ting Vit tng hp.

Hnh 4.1 S khi qu trnh tng hp ting Vit

Bt u

Vn bn u

vo (text)

Phn tch vn bn

thnh cc n v m

Tng hp

(Ghp ni)

Truy vn c

s d liu

Nng cao cht lng ting Vit tng

hp

c vn bn

(audio) Kt thc



40

4.2. Xy dng c s d liu

Xy dng c s d liu l bc rt quan trng trong qu trnh xy dng b

tng hp ting Vit cht lng tt. Bi vy, vic xy dng c s d liu phi p

ng cho h tng hp ting Vit cht lng tt theo quan im to li cc thanh

iu t nhin nht. Yu t dung lng ca c s d liu khng phi c t ln

hng u trong trng hp ny m chnh l cht lng thanh iu. xy dng

c b c s d liu tt, p ng yu cu nu trn, c hai vn c quan

tm. l c s d liu c xy dng s cho php tng hp c cc thanh

iu ging vi ting ni t nhin v cht lng tn hiu ting ni ghi m trong c

s d liu phi tt. Ngoi ra, chng ta cn gii quyt cc vn nh xy dng

ng liu y tha mn theo yu cu ra, chn ging thu v t chc kch

bn thu.

p ng cc yu cu nu trn, c s d liu c xy dng gm cc tp

tin ghi m, mi tp tin tng ng vi mt m tit c thu. Mi m tit c thu

s cha mt n v m c xc nh khi tng hp. Vi tng , bt k

mt m tit ting Vit no u c tch ra thnh hai n v m, m chng ti

gi l n v m u v n v m cui. Trong , n v m u s cha thnh

phn chnh l m u. n v m cui cha thnh phn chnh l m chnh trong

bng cu trc m tit ting Vit (Bng 2.2). Da theo kt qu nghin cu ca [7]

v cch phn chia mt m tit thnh hai n v m, cc n v m u s ng vi

thanh ngang, cn cc n v m cui ng vi tt c 6 thanh. V vy, khi xy

dng c s d liu cho cc n v m u s ch thu nhng n v m ng vi

thanh ngang. i vi n v m cui th thu y c 6 thanh.

4.2.1. Xy dng danh sch cc m tit cn thu

Da vo cu trc m tit ting Vit v dng cng c my tnh, chng ti

lp danh sch y cc m tit cha cc n v m cn thu. Cng vic xy



41

dng danh sch c thc hin bng phng php t hp nhm vt cn tt c

cc trng hp c th c i vi cc m tit ting Vit. Sau bc t hp, tin

hnh loi b cc trng hp khng c trong ting Vit, lc ra mt danh sch cc

m cn thu bng phng php th cng. Cc m tit c ghi m da trn s

lng cc n v m u v n v m cui c xc nh.

- Xy dng n v m u: Bng cch t hp cc ph m u vi nguyn

m chnh mang thanh ngang ta c 324 t hp. Tin hnh loi b th cng cc

t hp khng c trong ting Vit ta thu c 294 t hp. Chng hn loi b cc

t hp khng c trong ting Vit nh: ce, c, ci, nghu, ngh,

- Xy dng n v m cui: Bng cch t hp phn m m, m chnh v

m cui trong bng cu trc m tit ting Vit cui cng ta c 721 t hp c

trong ting Vit. C th, bng cch t hp m m vi m chnh v sau khi loi

b t hp khng c trong ting Vit ta c 187 t hp. Tip tc ly 187 t hp

ny t hp vi m cui s thu c 2244 t hp. Tip theo loi b cc t hp

khng c trong ting Vit s ch cn 721 t hp. Chng hn loi b cc t hp

khng c trong ting Vit nh: t, t, t, p, p, p, , i, , o,

Tng cng c 1015 t hp c xy dng v s t hp ny c kt hp

vi cc k t cn thit to thnh danh sch cc m tit cn thu. Trong s cc m

tit phi thu c mt s m tit c pht m trng nhau. V vy, khi thc hin thu

m ta ch cn phi thu 976 m tit.

4.2.2. Xy dng kch bn thu

Khi c danh sch y cc m tit cn thit, cn phi xy dng kch

bn thu nhm m bo cc n v m c thu cho kt qu tt nht.

i vi cc t hp m cui, thc hin ghp thm m /n/ hoc /t/ vo u cc

m ny. Th d, khi thu hai n v m cui ng, oan ta s cho cc m tit

tng, toan hoc nng, noan thu. Cch lm ny gip qu trnh tch cc m



42

tit v n v m trong danh sch ghi m s thun li hn rt nhiu, ng thi

cht lng vn c m bo.

gim ti mc thp nht hin tng ng cu m gia cc m tit, danh

sch cc m tit cn thu s c hin th mt cch c lp trn mn hnh my

tnh. Ti mi thi im ch cho php mt m tit cn thu c hin th v thi

gian hin th mt m tit l 1s.

4.2.3. Thu m

Thit b thu l my CSL Model 4500(Computerized Speech Lab, Model

4500) ca KayPENTAX chuyn dng thu v phn tch ting ni. Mi trng

thu c cch ly vi ting n bn ngoi phng thu. Qu trnh thu m c thc

hin ti phng thu ca Phng Th nghim Thit k in t, Trng i hc

Bch khoa H Ni. Tn hiu thu c ly mu tn s 16000Hz v 16 bit cho

mt mu. Ngi pht m s c u, r rng v dt khot cc m tit cn thu.

Vi tc pht m trung bnh l 250ms cho mt m tit, tng thi gian thu lin

tc ko di trong 244000ms (tc 244s).

Hnh 4.2 Thit b thu m CSL Model 4500

Thi gian thu mi b 976 m tit lin tc l 20 pht (tnh c thi gian ngh

gia cc m tit). Tng dung lng ca 1015 m tit l 10MB cho mi ging.

y l c s d liu xy dng phc v cho mc ch nghin cu. Vi cc ng



43

dng thc t, sau khi tch ly n v m u hoc n v m cui dng cho tng

hp, phn cn li s c ct b. Khi dung lng s gim ch cn khong

5,8MB. Theo kt qu tnh ton, t s tn hiu trn nhiu ca c s d liu

c xy dng trung bnh l 21dB. y l kt qu chp nhn c.

4.2.4. Tch ly m tit

Sau bc thu m, kt qu ta nhn c l mt c s d liu gm cc tp tin

d liu ghi m c nh dng *.wav. Bc tip theo, chng ta s thc hin tch

cc m tit t danh sch ghi m. Trong , mi m tit c tch s c lu ra

thnh mt tp tin tng ng v chng c t tn theo mt quy c thng nht.

y tn ca cc m tit s c t tn ca n v m m n s c ly ra khi

tng hp. V d: ta cn c n v m l on th ta s thu m ton v t tn l

oans.wav ging cch g ting Vit theo chun Telex. c th tch cc m tit

mt cch chnh xc nhm m bo khng mt thng tin khi tng hp, ta cn thc

hin theo cc bc sau y:

Bc 1: Tin x l, thc hin x l s b cc tp tin trong c s d liu thu,

nhm loi b nhng on nhiu, nhng m tit b li trong khi thu, ng thi

kim tra v sp sp th t cc m tit c thu theo ng danh sch cn thu, mc

ch ca vic kim tra v sp xp ny nhm c th t ng ha qu trnh tch m

tit. Tt c cc thao tc trong bc tin x l ny s c thc hin bi trn

chng trnh editsig c vit bng MatLab.

Bc 2: Thc hin ct m tit, sau khi thc hin tt qu trnh tin x l

i vi cc tp tin ghi m trong c s d liu thu. Bc tip theo, thc hin tch

cc m tit trong c s d liu thu ra thnh cc m tit c lp, mi m tit tng

ng vi mt tp tin ring. Qu trnh ny c thc hin nh sau: np tp tin ghi

m v tp tin cha danh sch tn cc m tit cn tch ra trong tp tin ghi m

tng ng vo trong chng trnh. Sau , qu trnh ct v lu cc m tit c



44

thc hin t ng bng chng trnh silencedetect. Tuy nhin, m bo vic

ct c thc hin chnh xc, thng thng trc khi thc hin ct t ng

chng ta nn c thao tc kim tra th cng ton b cc im ct m chng trnh

d tm c xem chng c t ng v tr hay cha, nu cn ta c th

iu chnh cho ph hp ngay trn giao din chng trnh, trong trng hp c

qu nhiu t thiu chnh xc th ta c th trc tip thay i cc tham s ca

chng trnh nh: gi tr ngng nng lng ca on tn hiu bt u v kt

thc ca m tit, kch thc ca s x l, Sau ta cn cp nht cc tham s

ny qu trnh d tm c thc hin li vi tham s mi v c tip tc kim

tra nh vy. Qu trnh ny c thc hin cho ti khi no chng ta nhn thy kt

qu l chnh xc th lc qu trnh ct v lu tp tin mi c thc hin t

ng.

Hnh 4.3 Giao din x l ca chng trnh editsig

Trong c s d liu ting Vit, khi ct m tit ta c bit lu i vi danh sch

cc n v m u nh ta, xa, cha, nha, la, sa, da,. Nu chng c lu trn



45

cng mt tp tin d liu ghi m th qu trnh d tm cc im ct thng khng

chnh xc cho tt c cc m tit trong danh sch ny. S d l trong danh sch tn

ti mt s m tit c cha k t khi pht m l v thanh nh m tit xa, sa, v

mt s m tit khc th khng nh t la, nha, v th cc tham s thit lp

trong chng trnh khng th ph hp cho c hai loi m tit ny khi d tm

im ct. V vy, i vi cc trng hp ny th thng ta cn phi kim tra

iu chnh trc tip trn giao din chng trnh bng tay trc khi thc hin vic

ct t ng minh ha hnh 4.4.

Hnh 4.4 Giao din x l ca chng trnh silencedetect.

Bc 3: Thc hin qu trnh lp tng t vi bc1 v bc 2 i vi cc

tp tin khc trong c s d liu cho ti khi kt thc.

4.2.5. Tch ly n v m

Vic tch ly cc n v m trong cc m tit tng ng c thu v tch

ra trn l yu t rt quan trng, vic lm ny c nh hng trc tip n cht

lng ting ni tng hp sau ny. Hn th na, cng vic ny i hi rt nhiu



46

thi gian v cng sc thc hin. Chnh v vy, ngay t khi thu m, chng ti

phi tnh n vn ny v xy dng kch bn tht chi tit sao cho c th thc

hin vic tch cc n v m mt cch d dng nht. Th d, i vi cc n v

m u, chng ti chn cc m c bt u bng t hoc n khi thu. S d

chn m t v thi gian pht m t trong mt m tit l rt ngn, nn khi tch ta

cng d dng c lng c phn tn hiu ca m ny trong m tit cn thu.

Cn i vi m n ta rt d nhn ra phn tn hiu ca m n nn vic tch cc

m cng tr ln d dng hn. Tt c cc l do nu u a n mt mc ch

chung l c th thc hin vic tch n v m trong t mt cch nhanh chng, d

dng v chnh xc. Tuy nhin, c c s d liu tt th nht thit vic tch cc

n v m vn cn rt nhiu cng sc, kinh nghim cng nh kin thc chuyn

mn trong vic phn tch tn hiu cng nh phn tch ng m hc.

thc hin qu trnh tch cc n v m c nhanh, chnh xc v trc

quan, trong ti ny chng ti c s dng ti chng trnh psolatools h tr

qu trnh tch. V th, thi gian thc hin tch gim i ng k nhng vn

m bo tnh chnh xc cao. Chng trnh c h tr mt s chc nng nh chc

nng tng hp. Chc nng ny cho php ngi dng c th tng hp trc tip

cc n v m va tch nh gi cht lng, t c iu chnh kp thi v tr

im ct nu cn. y l c s d liu xy dng nhm mc ch cho nghin cu,

nn thng tin v im ct c xc nh v lu mt tp tin c nh dng

sn. Tp tin ny c tn trng vi tn tp tin ghi m, nhng c nh dng khc(*

.pim) cn tp tin ghi m tng ng ban u vn c bo ton nguyn vn.

Chnh v iu ny m thng tin v im ct sau khi c xc nh c th iu

chnh li nu cn nhm nng cao cht lng ting ni c tng hp.



47

Hnh 4.5 Giao din x l ca chng trnh psolatools.

4.2.6. X l cc im ct v lu tr d liu

Ngoi vic xc nh ng cc m cn tng hp trong m tit thu, chng

ta cn phi x l chnh xc cc im ct v lu thng tin ny vo tp tin d liu

c nh dng *.pim. m bo qu trnh ghp cc n v m khi tng hp c

tt, cc im ct cn tha mn cc iu kin sau:

im ct c xc nh trong vng n nh ca tn hiu, tc l on tn hiu

t c s bin thin nht v mt bin , ph.

im ct phi nm trong phn n nh ca nguyn m.

im ct phi l im c gi tr cc i hoc cc tiu a phng trong

vng c ct khi tng hp trnh s lch pha (trong ti ny ti chn

im ct ti im c bin cc tiu)

phc v tt qu trnh tng hp sau ny, trong cc tp tin *.pim c cha

thng tin v v tr im ct ca cc n v m u, ngoi ra cn lu thm cc

thng tin v v tr ca im chuyn tip gia ph m v nguyn m trong n v



48

m u v cc im cc tiu trong on ny, nh minh ha trn hnh 4.7 v hnh

4.8. Cng vic ny c thc hin nhm phc v d liu u vo cho mt s gii

thut xut s c thc hin khi tng hp. Nh vy, c s d liu c xy

dng gm cc n v m u v n v m cui vi tng l 1015 n v m

tng ng vi 1015 tp tin ghi m(*.wav) v 1015 tp tin d liu (*.pim).

Hnh 4.6 Dng tn hiu ca m tit na

Hnh 4.7 Dng tn hiu ca m tit na c tch ly n v m u

Hnh 4.8 on tn hiu ca n v m u( m _na)

( im A: im ct. im E: v tr chuyn tip gia ph m n v nguyn m a

trong n v m _na. im A, B, C, D, E: cc cc tiu a phng ca on

tn hiu nguyn m a. on EF l on tn hiu ca ph m n)

4.3. X l v phn tch vn bn



49

D liu u vo ca b tng hp l mt vn bn dng text. V vy, trc khi

tng hp ta cn x l, phn tch vn bn u vo nhm bin i on vn bn

u vo thnh cc m tit v cc n v m tng ng. Qu trnh x l v phn

tch bao gm cc thao tc c trnh by sau y.

4.3.1. Phn tch vn bn ting Vit thnh cc m tit

Qu trnh phn tch vn bn thnh cc m tit bao gm ba thao tc: Chuyn

vn bn ting Vit c du v dng text, xc nh cu trong vn bn v x l cu,

phn tch cu thnh cc m tit. Trong chng trnh ny, vn bn ting Vit khi

a vo tng hp u c phn tch ra thnh dng vn bn c biu din theo

kiu g Telex. V d: cm m tit ting Vit l Trng i hc Nha Trang s

c chuyn sang dng vn bn l truwowngf ddaij hocj nha trang.

4.3.2. Xc nh cu trong vn bn

Cu trong vn bn gm nhiu loi cu (trn thut, nghi vn...). Cc loi du

cu bao gm du chm, du phy, du chm than, du hai chm, du hi, Tuy

nhin, vi mc ch nghin cu gii thut tng hp ting Vit bng phng php

ghp ni nhm tng hp cc m tit mt cch t nhin nht, nn trong lun vn

ny chng ti coi cc cu trong vn bn tng hp ch dng cu trn thut.

Vn bn c th coi l mt xu k t. u tin xu c quy ht v ch

thng ng b vi cch lu tr tn ca cc n v m trong c s d liu.

Qu trnh x l cu c thc hin nh trn hnh 4.9



50

Hnh 4.9 Lu thut gii xc nh cu trong vn bn

4.3.3. Phn tch cu thnh cc m tit

Cu bao gm nhiu t. Mt t c th c mt hoc nhiu m tit. Sau khi

tch c cu, ta tin hnh tch cc m tit. Gii thut tch mt cu thnh cc

m tit nh minh ha trn hnh 4.10.

Hnh 4.10 Lu thut gii xc nh m tit trong cu

Bt u

Nu ht

vn bn Kt thc

S

c k t

L du kt

thc cu

Lu k t

X l cu

S

Bt u

Nu ht

cu Kt

thc

S

c k t

K t cui

m tit

Lu k t

X l m

tit

S



51

4.3.4. Tch m tit thnh hai n v m

Tch mt m tit thnh hai n v m theo quy tc: duyt ln lt tng k

t, tm n v tr nguyn m u tin trong m tit. Chui k t bn tri nguyn

m (bao gm c nguyn m) l n v m u, chui k t bn phi nguyn m

(bao gm c nguyn m) l n v m cui. Lu tch m tit c trnh by

trn hnh 4.11.

Hnh 4.11Lu thut gii tch m tit thnh n v m u v n v m cui

4.4. Tng hp ting Vit cht lng tt

4.4.1. Tng hp ting Vit bng phng php ghp ni.

Qu trnh tng hp c thc hin bng cch ghp ni trc tip cc n v

m c thu t ting ni t nhin, c x l v lu trong c s d liu.

Phng php tng hp ny thng cho cht lng tng hp l t nhin nht so

vi cc phng php c gii thiu trong chng 3. S dng phng php

Bt u

Nu l

nguyn m

Kt thc

c k t

S

Xc nh n v

m u

Xc nh n v

m cui



52

ny chnh l mun ca chng ti nhm xy dng b tng hp c kh nng tng

hp ting Vit ging vi ting ni t nhin nht.

Sau y l cc bc tng hp mt m tit ting Vit:

Bc 1: Xc nh n v m u v n v m cui ca m tit cn tng hp.

Bc 2: c d liu t hai tp tin ghi m (*.wav) trong c s d liu c tn

tng ng vi tn ca hai n v m xc nh ti bc 1.

Bc 3: c thng tin trong tp tin dng *.pim ly thng tin v im ct.

Bc 4: Thc hin tng hp bng vic ghp n v m u vi m cui.

Hnh 4.12 Lu thut gii tng hp m tit bng phng php ghp ni

Nh ni trn, trong khun kh ca lun vn chng ti cha quan tm

n phn x l ng iu. Do , ton b cc cu trong vn bn u c c ra

di dng cu trn thut. Chng c tng hp da trn cc m tit n l sau

ghp li v x l theo dng cu trn thut.

Bt u

Kt thc

c tn hiu ca 2 n v

m t c s d liu

Xc nh im ghp ca n v

m u vi n v m cui

Ghp n v m u v n v

m cui to thnh mt m tit

Xc nh hai n v m

tng hp



53

4.4.2. Mt s xut nhm nng cao cht lng tng hp

t vn : Tng hp ting ni bng phng php ghp ni t cc n v

m khng ng nht (non-uniform unit) l vn c thc hin t rt sm.

Tuy nhin, cho n nay nhng tn ti ca vn ny vn lun mang tnh thi s

v thu ht nhiu s quan tm. l vic x l tn hiu ti im ghp ni. Gi

thit rng tn hiu ca cc n v m cn tng hp trong c s d liu l rt tt,

song cht lng tng hp ca t hoc m tit c th li khng tt trong mt s

trng hp. S d l do on tn hin ti v tr ghp ni khng lin tc. Ni khc

i, cc tham s tn hiu ting ni ti v tr ghp ni thng c s chnh lnh v

gi tr. Gi tr chnh lnh ny cng ln th ting ni tng hp c cht lng cng

km. C nhiu nguyn nhn, nhng nguyn nhn chnh l do hai n v m c

ghp vi nhau khi tng hp th c thu bi mt ging, tuy nhin chng li c

thu vo hai thi im khc nhau, khi thu chng c thu trong ng cnh khc,

iu ny dn ti cc tham s ca chng l khng ging nhau khi chng c

ghp ni tng hp.

Bng tm hiu v nhng nh hng ca cc tham s c bn n cht lng

ting ni ting Vit c tng hp bng phng php ghp ni, chng ti c th

ch ra mt s tham s c bn c nh hng nh sau:

Bin

Tn s c bn F0

Ph (hay cc formant)

Cc tham s ny c th d dng nhn ra khi ta quan st tn hiu trong min

thi gian hoc tn s trn hnh 4.13 v hnh 4.14



54

Hnh 4.14 cho thy s gin on v khng lin tc ca cc tham s bin ,

ph v tn s c bn F0 so vi tn hiu gc trn hnh 4.13.

Trn th gii c rt nhiu cng trnh nghin cu v vn ny, tuy nhin

mi ngn ng li c nhng c trng ring, nn chng cng cn c nhng cch

gii quyt khc nhau. V vy, trong phn tip theo chng ti xin trnh by cc

xut cn bng tham s nh bin , tn s c bn F0 v ph i vi ting Vit.

Sau y l cch gii quyt c th ca chng ti cho tng tham s.

4.4.2.1. Cn bng bin

cn bng bin c rt nhiu cch thc hin, tuy nhin vic cn bng

phi m bo on tn hiu ting ni sau khi c cn bng c t thay i nht so

vi tn hiu gc ban u. Da trn c s , tng ca chng ti l qu trnh

cn bng bin ca t tng hp s c cn bng bin ca n v m u

theo n v m cui. S d chn n v m u v on tn hiu ca n v m

Hnh 4.14: Tn hiu ting ni ca t ti

sau khi ghp n v m u v n v m

cui.

(A) on tn hiu ca n v m u

(B)on tn hiu ca n v m cui

Hnh 4.13: Tn hiu ting ni t nhin

ca t ti

(A) Biu din min thi gian

(B) Biu din cc formant

(C) Biu din F0



55

u thng ngn hn so vi n v m cui, v th khi cn bng chng s t b

nh hng hn. Mt v d minh ha cho trn hnh 4.15.

Cc bc thc hin nh sau:

Bc 1: Tm gi tr bin ln nht ca n v m u v n v m cui.

Bc 2: Tnh h s tng ng bng cch ly gi tr ln nht ca n v m

cui chia gi tr ln nht ca n v m u.

Bc 3: Tnh li cc gi tr ca cc mu ca n v m u bng cch nhn

cc mu vi h s tnh bc 2.

4.4.2.2. Cn bng tn s c bn F0

Tn s c bn F0 l mt trong nhng tham s quan trng ca tn hiu ting

ni. i vi ting Vit, khi thay i tn s F0 th s lm thay i thanh iu, ng

iu ca ting ni v nhiu thng tin quan trng khc trong ting ni tng hp.

V vy, vic cn bng tham s F0 l iu rt quan trng nhm nng cao cht

lng ting Vit tng hp.

Nhiu gii php c a ra cn bng tn s c bn F0 ti v tr ghp

ni nh mt s thut gii shift only, residual resampling, multiplex window

processing trong cc bi bo [4], [8]. Tuy nhin, tng y ca chng ti l

s thay i gi tr F0 trong on tn hiu nguyn m ca n v m u theo gi

(b)

(a)

Hnh 4.15 Tn hiu ting ni tng hp ca t ti

(a). Cha cn bng bin . (b). cn bng bin



56

tr F0 bn n v m cui. Phng php ny c chng ti thc hin bng thut

gii PSOLA.

Gii php v cc bc thc hin nh sau:

Bc 1: Xc nh tn s c bn on nguyn m ca n v m u v n

v m cui gi tng ng l F01 v F02

Bc 2: Thay i tn s F01 ca on tn hiu nguyn m bn n v m

u theo tn s F02 bn n v m cui bng thut gii PSOLA.

Hnh 4.16 l kt qu phn tch tn s F0 sau khi tin hnh ghp n v m

u v n v m cui ca t ti. ng (a) l F0 ca t trc khi thc hin

cn bng F0. ng (b) l F0 ca t sau khi thc hin cn bng F0.

Hnh 4.16 Tn s c bn F0 ca t ti c tng hp

(a). Cha cn bng F0. (b). cn bng F0



57

4.4.2.3. Lm trn ph

Qu trnh lm trn ph ti v tr ghp ni s c thc hin sao cho, cn

bng ph ca on tn hiu nguyn m bn n v m u chng lin tc vi

ph ca phn nguyn m bn n v m cui. tng lm trn ph c thc

hin bng cch tng hp li on tn hiu nguyn m ngay trc v tr ghp ni

bn n v m u bng phng php LPC. Mc ch l to ra tn hiu mi vn

m bo mang mt phn thng tin ca on tn hiu ban u, song thng tin v

ph s c iu khin gn ging vi ph on tn hiu ca phn nguyn m

bn n v m cui.

Qu trnh c tin hnh theo cc bc nh sau: Tm cc h s LPC ca

on tn hiu nguyn m bn n v m u ( y k hiu l ai1) v cc h s

LPC ca on tn hiu nguyn m thuc n v m cui ( y k hiu l ai2).

Sau , cc tham s ai1 c s dng tnh tn hiu kch thch cho tuyn m.

Cc h s ai2 s c s dng lm tham s ca tuyn m khi tng hp.

Cc bc thc hin c th nh sau:

Bc 1: Tnh gi tr ai1 v ai2 ca hai on tn hiu trc v sau im ghp

ni. S dng phng php LPC (s dng thut gii Levinson-Durbin).

Bc 2: Tnh xung kch thch ca on tn hiu nguyn m bn n v m

u theo cng thc (3.2).

Bc 3: Tng hp li on tn hiu hu thanh bn n v m u bng cch

s dng xung kch thch c tnh bc 2 v cc h s ai2 tng hp. Chi tit

v cc bc ny c th hin hnh 4.17

Hnh 4.18 cho thy s chnh lnh gia ng bao ph ca on tn hiu gc

ca n v m u ng vi ng (a) so vi ng bao ph ca on tn hiu

trong n v m cui ng vi ng (b) l rt ln, c bit l trong vng I, vng

II v vng III. Tuy nhin, sau khi s dng thut gii lm trn ph, th s



58

chnh lnh ny gim i ng k. ng bao ph ca on tn hiu mi sau

khi s dng thut gii lm trn ph ng vi ng (c).

Hnh 4.17 Qui trnh lm cn bng ph ti v tr ghp ni

(a). on tn hiu ti v tr ghp ni ca n v m u

(b). on tn hiu ti v tr ghp ni ca n v m cui

(c ). on tn hiu mi c tng hp bng phng php lm trn ph

+

Tnh h s tin on LPC: ai1

i=1..P (P=8..14)

Tnh h s tin on LPC: ai2

i=1..P (P=8..14)

Tnh tnh hiu kch thch:

p

k

knykanynynyne1

1~

Tng hp tn hiu: y1

p

k

knykaneny1

121 )()(

(a) (b)

( c)



59

Hnh 4.18 ng bao ph cc on tn hiu trc v sau x l ca t ti

(a) .ng bao ph on tn hiu thuc n v m cui (b) .ng bao ph on tn hiu trc cn bng ph thuc n v m u (c) .ng bao ph on tn hiu sau khi cn bng ph

Hnh 4.19 Kt qu cn bng ph ca t ti (a) trc (b) sau cn bng

(a) (b)



60

Hnh 4.20 Kt qu tng hp ca t ti p dng c ba php cn bng

(a). Cn bng bin

(b). Cn bng ph v bin

Hnh 4.20 l kt qu tng hp ca t ti sau khi cn bng c ba tham s

bin , tn s c bn F0 v ph theo cc thut ton nu trong mc 4.4.2.

Trn hnh 4.20a tn hiu ca t ti c biu din trn min thi gian, bng

quan st cho thy s chnh lnh bin gia n v m u v m cui ca t l

nh hn rt nhiu so vi thi im cha cn bng nh c minh ha trn

hnh 4.15a. Trn hnh 4.20b l biu din tn s c bn F0 v ph ca t Ti,

qua quan st cho thy, gi tr tn s c bn F0 gn nh lin tc li v tr ghp ni.

Tng t i vi ph, th t ca cc formant bn n v m u v n v m

cui nhng ci thin ng k so vi thi im cha cn bng hnh 4.19a.

(a) (b)



61

Hnh 4.21 Giao din chng trnh tng hp ting Vit t vn bn

4.5. nh gi cht lng ting Vit tng hp

4.5.1. Xy dng kch bn nh gi

Nhm nh gi hiu qu ca cc gii thut ci thin ting Vit tng hp

nu trong mc 4.4.2 ng thi nh gi cht lng ting Vit tng hp so vi

ting ni t nhin, chng ti thc hin qu trnh nh gi ny bng phng

php trc nghim. Qu trnh nh gi c c thc hin da trn 20 cu trc

nghim c nh gi bi 30 ngi nghe. Phn nh gi bao gm hai phn:

Phn mt l nh gi kt qu ca cc thut gii xut nhm nng cao cht

lng tng hp bng gii php lm trn cc tham s tn hiu ting ni ti v tr

ghp ni. Phn hai nh gi cht lng ting ni ca b tng hp ting Vit so

vi ting ni t nhin. Thang im nh gi phn ny l thang im 5 ( 1:

bad, 2: Poor, 3: Fair, 4: Good, 5: Excellent) theo chun MOS (Mean Opinion

Score). B trc nghim nh gi gm 20 t c tng hp theo hai dng. Dng

mt l cc t c tng hp cha s dng cc phng php ci thin cht lng,



62

dng hai l cc t c tng hp s dng cc phng php ci thin cht

lng nu trong mc 4.4.2.

Qu trnh nh gi c thc hin nh sau: i vi phn mt, ngi nghe

s thc hin nh gi tun t 20 t nu trn. Ngi nghe s c nghe tng t

mt, mi t c nghe c hai dng, sau s nh gi xem dng no ca t

c nghe c cht lng tt hn. Trng hp khng phn bit c th c th

chn p n l ging nhau. i vi phn 2, ngi nghe s nghe v nh gi cho

im theo thang im 5, mu nh gi cho trn hnh 4.22.

Hnh 4.22 Mu nh gi trc nghim

4.5.2. Kt qu nh gi cht lng ting Vit tng hp

Chng ti ngh 30 ngi nghe nh gi cht lng ting Vit tng

hp. Hnh 4.23 cho thy kt qu nh gi ny. Trong 20 t c a ra nh gi,

vic nh gi cht lng tng hp l tt t ra vt tri v pha cc t c ci

thin. c bit i vi t ti th 100% ngi nghe chn t ny sau ci tin c

cht lng tt hn, ngoi ra c mt s t khc c kt qu tng t cng kh cao

nh t n, cn, cuc, i, i, C mt s t nh t, vi th s

ngi nh gi cho cc t cha c ci thin c cht lng tt l kh cao, song

con s ny vn t hn so vi s ngi nh gi cho t c ci thin l tt

T tng hp

Chn mt p n

(nh du ct c chn)

So vi ting ni t nhin

(Bn nh gi my im nh du

vo mt trong nm ct tng

ng vi s im )

A tt B tt A ging B

V d

1. Ti

2. n

.

.

.



63

hn. Nguyn nhn c th l do ngi nghe khng c tp trung, hoc cha c

phn tch tinh t khi nghe, hoc thm ch cng b nh hng bi th t pht m

khi nghe(thng t pht sau c nh gi nhnh hn nu cht lng ca chng

khng khc nhau nhiu). Chnh v nhng l do ny m mt s t c s khc nhau

khng nhiu s i khi ngi nghe chn cho t cha c ci tin hoc chn

phng n l cht lng ging nhau.

Hnh 4.23Kt qu nh gi cht lng ca 20 t trc v sau khi c ci thin

Bng 4.1 ch ra kt qu nh gi v cht lng ca 20 t theo phng php

MOS. Kt qu nh gi ca mi t c tnh trung bnh cng ca 30 ngi nghe.

Kt qu ny cho thy, gi tr trung bnh ca 20 t c nh gi u cho gi tr

ln hn 4. i chiu vi thang im 5 nu, th y l kt qu cho thy cht

lng t tng hp t mc t nhin kh cao.



64

Bng 4.1 Kt qu nh gi cht lng ca 20 t ting ni tng hp

T im TB cng

(30 ngi nghe) T

im TB cng

(30 ngi nghe)

Ti 4.467 ng 4.1

n 4.433 Cuc 4.566

Hi 4.267 i 4.5

Cn 4.7 T 4.467

Gii 4.467 T 4.466

Tin 4.667 Tng 4.267

Giy 4.4 Vi 4.6

Bao 4.3 Ca 4.633

Di 4.567 Phng 4

Tnh 4.533 i 4.633



65

CHNG 5: NH GI KT QU V HNG PHT TRIN

5.1. Kt qu t c ca lun vn

Trong lun vn ny, chng ti nghin cu cc phng php tng hp

ting ni ni chung v tng hp ting Vit ni ring. ng thi, cng tm hiu

v phn tch cc c trng c bn ca ng m ting Vit v cu trc m tit ting

Vit nhm phc v cho nghin cu tng hp ting Vit. Hn th na, lun vn

cn nh gi nhng nh hng ca mt s tham s tn hiu ting ni n cht

lng tng hp ting Vit bng phng php tng hp ghp ni. T y, lun

vn c xut nhm xy dng b tng hp ting Vit cht lng tt.

Chng ti xy dng b c s d liu ring phc v cho vic tng hp

ting Vit cht lng tt. Ngoi ra, c s d liu c xy dng vn c th s

dng tt cho vic nghin cu v cc ng dng tng hp khc, c bit l tng

hp ting Vit bng phng php ghp ni. V vn xy dng c s d liu

cho b tng hp, chng ti gi bi bo Xy dng c s d liu cho tng hp

ting Vit cht lng tt tham gia Hi ngh quc gia Mt s vn chn lc

ca cng ngh thng tin v truyn thng v trnh by ti Hi ngh vo ngy

7-8/8/2009 ti Bin Ha, ng Nai.

Trong lun vn chng ti xy dng b tng hp ting Vit da trn c s

ng liu nu trn tng hp ting Vit bng phng php ghp ni. Trong

ba phng n c xut nhm nng cao cht lng ting Vit tng hp

bng cch lm trn cc tham s tn hiu ting ni tng hp ti v tr ghp ni.

Trong , phng php lm trn ph ti v tr ghp ni do chng ti xut l

mi i vi ting Vit.

Chng ti thc hin nh gi kt qu ting Vit tng hp bng phng

php trc nghim da trn 20 t tng hp vi 30 ngi nghe. Trong qu trnh th

nghim kt qu tng hp, y l nhng t theo cm nhn ch quan ca chng ti



66

nn c u tin nh gi cht lng hn c. iu ny c ngha l, s c nhng

t m cht lng trc v sau khi ci thin hu nh u tt nh nhau, do trc

khi ci thin cht lng rt tt v nh vy, khng nht thit phi u tin a

vo danh sch cc t cn nh gi. Nhng t c a vo nh gi l nhng t

c s chnh lnh v mt tham s tng i ln v tr ghp ni trc khi c

ci thin cht lng. Chnh v vy, nhng kt qu bc u cho thy, cc xut

c chng ti s dng nhm cn bng cc tham s tn hiu ting ni ti v tr

ghp ni l rt tt, cht lng ting Vit ca nhng t tng hp l rt ging vi

ting ni t nhin.

5.2. Hn ch v hng pht trin

Mc d t c nhng kt qu rt kh quan, song cht lng ting Vit

c tng hp mi dng li dng cu trn thut. Trong khun kh ca lun

vn, chng ti cha c iu kin tng hp ting Vit vi cc ng iu khc

nhau. nng cao cht lng tng hp vn bn chng ta cn xt n ngn iu

ca cu. ng thi chng ta cng cn phi x l tt cc con s, cc t vit tt v

c t ting nc ngoi trong vn bn b tng hp c th tng hp bt k mt

vn bn no.

Bng cch lm tng t, chng ta c th to mi cc b c s d liu cho

tng hp ting Vit cht lng tt theo la tui, gii tnh, vng min nhm tng

hp c nhiu loi ging khc nhau, k c cc ging a phng.



67

TI LIU THAM KHO

[1]. L Trung Dng, Xy dng cng c kho st nh hng ca cc tham s c

bn n cht lng ting ni b tng hp ting Vit dng TD-PSOLA , Lun

vn Cao hc, i hc Bch khoa, nm 2007.

[2]. Nguyn Hu Qunh, Ng Php Ting Vit Nh xut bn t in Bch

khoa, tr.11-86, HN, 2001.

[3]. L Th Vinh Tng hp v nhn dng ting Vit trn h nhng T-Engine

SH7760 Lun vn cao hc, i hc Bch khoa, nm 2007.

[4]. Baris Bozkurt, Thierry Dutoit, Romain Prudon, Christophe DAlessandro,

Vincent , Improving quality of mbrola synthesis for non-uniform units synthesis

, Park, B-7000 Mons, Belgium.

[5]. Trn t, Eric Castelli, Serignat Jean-Francois, L Xun Hng, Trnh

Vn Loan. Influence of F0 on Vietnamese syllable perception. Proc. of

Interspeech 2005, Lisbon, pp 1697-1700, 2006.

[6]. Trn t, Eric Castelli, Trnh Vn Loan, L Vit Bc, Building a large

Vietnamese Speech Database. Tp ch Khoa hc v Cng ngh (ISBN 0868-

3980) Vol 46/47, February 2004, pp 13-17.

[7]. Trn t, Eric Castelli, Serignat Jean-Francois, Trnh Vn Loan, L

Xun Hng. Linear F0 Contour Model for Vietnamese Tones and Vietnamese

Syllable Synthesis with TD-PSOLA. Proc. TAL 2006, La Rochelle, April 2006.

[8]. M. Edgington and A. Lowry,Residual-Based Speech Modification

Algorithms for Text-to-Speech Synthesis, BT Laboratories, Martlesham Heath,

IPSWICH, IP5 7RE, U.K.

[9]. Hansjrg Mixdorff, Nguyen Hung Bach, Hiroya Fujisaki, Mai Chi Luong,

Quantitative Analysis and Synthesis of Syllabic Tones in Vietnamese,

EuroSpeech 2003 GENEVA.

[10]. Nguyen Thanh Kien, Nguyen Duc Thang, Le Thai Hoa, Trinh Van

Loan,DSP-based Embedded System for Text to Speech Synthesis of

Vietnamese, Proceeding of the 2nd Asia Pacific International Conference on

Information Science and Technology, Hanoi, December 2007 pp 215-219.

[11]. L Th Vinh, Trnh Vn Loan, Vietnamese Recognition and Synthesis with

T-engine Embedded System, Proceeding of the 2nd Asia Pacific International

Conference on Information Science and Technology, Hanoi, December 2007

pp133-137.

[12]. Thierry Dutoit "An Introduction to Text-to-Speech Synthesis" 1997

[13]. Xuedong Huang, Alejandro Acero, Hsiao-Wuen Hon, PH Spoken

Language Processing - A Guide to Theory, Algorithm and System Developmen

October 2000.

[14]. Phn mm: Praat, WaveSufer, WASP, Adobe Audition 1.5.

[15]. URL: http://ngonngu.net



68

PH LC A DANH SCH CC M CN THU

=================Phn n v m u ==========================

ba b b be b bi bo b b bu b

ca c c co c c cu c

cha ch ch che ch chi cho ch ch chu ch

da d d de d di do d d du d

a e i o u

ga g g ge g gi go g g gu g

ghe gh ghi gia gi gi gie gi gi gio gi gi giu gi

ha h h he h hi ho h h hu h hy

ka ke k ki ky kha kh kh khe kh khi kho kh kh khu kh

la l l le l li lo l l lu l ly

ma m m me m mi mo m m mu m my

na n n ne n ni no n n nu n

nga ng ng ngo ng ng ngu ng

nghe ngh nghi nha nh nh nhe nh nhi nho nh nh nhu nh

pa p pi p p pu py pha ph ph phe ph phi pho ph ph phu ph

qua qu qu que qu qui qu qu quy

ra r r re r ri ro r r ru r

sa s s se s si so s s su s sy

ta t t te t ti to t t tu t ty

tha th th the th thi tho th th thu th

tra tr tr tre tr tri tro tr tr tru tr

va v v ve v vi vo v v vu v vy

xa x x xe x xi xo x x xu x xy

a n n n n n n n n n n n n

e i o

u

y b c d g h k l m n p q r s t v x w f j z

================n v m cui==============================

ai ay ao au am an ang anh

i y o u m n ng nh

i y o u p t c ch m n ng nh

i y o u m n ng nh

i y o u p t c ch m n ng nh

i y o u m n ng nh

m n ng m n ng p t c m n ng m n ng

p t c m n ng m n ng

y u m n ng



69

y u m n ng

y u p t c m n ng

y u m n ng

y u p t c m n ng

y u m n ng

eo em en eng o m n ng o p t c m n ng

o m n ng o p t c m n ng

o m n ng u m n nh

u m n ng nh u p t ch m n

dng nh u m n ng nh

u p t ch m n ng nh

u m n ng nh

iu im in inh u m n nh

u p t c ch m n nh u m n nh

u p t c ch m n nh u m n nh

oi om on ong i m n ng

i p t c m n ng

i m n ng i p t c m n ng

i m n ng i m n ng



i m n ng i m n i m n i p t m n

i m n i p t m n i m n

ui uy um un ung i y m n ng

i y p t c m n ng i y m n ng

i y p t c m n ng i y m n ng

u n m ng u m n ng u t c m ng

i u m ng u t c m ng u m ng

uynh unh t unh unh t unh unh

ia a a a a a iu im in ing

iu im in ing iu ip it ic im in ing

iu im in ing iu ip it ic im in ing

iu im in ing ua a a a a a

ui um un ung ui um un ung

ui ut uc um un ung ui um un ung

ui ut uc um un ung ui um un ung

a a a a a a i u m n ng

i m n ng i u t c m n ng

i ng i u t c m n ng

i m n ng oa oai oay oan oang oanh

a oi oy on ong onh a oi oy ot oc och on ong onh



70

a oi oy on ong onh

a oi oy ot oc och on ong onh

a oi oy on ong onh on ong

on ong ot oc on ong on ong

ot oc on ong on ong

oe e e ot e e ot e

oen on on on on on

oong ong ong ong ong ong oc oc

uy un ung uy un ung uy ut un ung

uy un ung uy ut lun ung uy un ung

u u u uch uch unh unh unh unh unh

unh u u u ui i i i i i uy uynh

y unh y ut uch unh

y uu unh y uu ut uch unh

y unh uyn uyn uyt uyn uyn

uyt uyn uyn u u uya ua

yu yn yu ym yn yu ym.



71

PH LC B Bi bo 1 XY DNG C S D LIU CHO TNG HP

TING VIT CHT LNG TT

Tc gi: Ts. Trnh Vn Loan, inh ng Lng, Phm Th Kim Ngoan

Hi ngh Mt s vn chn lc ca cng ngh thng tin v truyn thng c

quan ch tr Vin cng ngh thng tin, thng 8/2009 ti Bin Ha, ng Nai

Tm tt

Ting Vit l ngn ng n m tit v c thanh iu. V vy, to ra b

tng hp ting Vit c cht lng cao, nht thit phi tng hp c cc thanh

iu sao cho cng gn vi ting ni t nhin cng tt. Qua thc t v nghin cu

v tng hp ting Vit, chng ti xut cch tip cn mi trong s a yu

t cht lng tng hp thanh iu ln hng u trong qu trnh xy dng c s

d liu. Ngoi ra, c s d liu do chng ti xy dng vn c th s dng tt cho

cc ng dng tng hp khc, c bit l tng hp ting Vit bng phng php

ghp ni.

T kho: c s d liu ting Vit, cht lng tt, thanh iu, ghp ni.

Abstract

Vietnamese is a monosyllabic and tonal language. Therefore, in order to

make high-quality synthesized Vietnamese units, it is necessary to synthesize six

tones whose characteristics are as close to natural language as possible. In this

paper, we propose a new approach to build Vietnamese databases for

synthesizing the tones of Vietnamese with good quality. In addition, the

databases can be used for other Vietnamese synthesis applications using

concatenation synthesis method.

1. Gii thiu

Hin nay, vic tng hp ting Vit c mt s kt qu bc u. Tuy

nhin, nhng kt qu t c ca cc b tng hp ny cn mc hn ch. Qua

thc t v nghin cu v tng hp ting Vit, chng ti nhn thy cht lng

tng hp ting ni ting Vit ph thuc phn ln vo cht lng tng hp thanh

iu v cht lng c s d liu c xy dng. Vic xy dng c s d liu

m bo hai yu t nu trn c chng ti trin khai nhm phc v cho b tng

hp ting Vit cht lng tt. Trong , yu t cht lng tng hp thanh iu

c a ln hng u trong qu trnh xy dng c s d liu. Trong bi bo

ny, phn u s trnh by mt s c im c bn ca ng m ting Vit lm

nn tng xy dng c s d liu ting Vit trong trng hp ca chng ti.

Phn tip theo m t chi tit cc bc c tin hnh xy dng c s d

liu phc v cho tng hp ting Vit cht lng tt theo phng php ghp ni

v phn cui cng l nh gi kt qu t c.



72

2. c im c bn ca ng m ting Vit

Ting Vit l ngn ng n m tit, cc t trong ting Vit khng bin i

hnh thi, khng bin i ui v t biu th cc phm tr ng php. Cu to

t khng dng ph t v dng rt t hnh v. Ting Vit l ngn ng phn tch.

Trong ting Vit khng tn ti ranh gii gia m tit v hnh v. Mi m tit l

mt hnh v. T vng ca ting Vit phn ln c cu to t mt hoc hai hnh

v, c tnh n tit, song tit, mt s l t a tit.

Ting Vit l ngn ng c thanh iu gm su thanh: ngang (khng du),

huyn, sc, nng, hi v ng. Thanh iu trong ting Vit c chc nng nh mt

m v, n tham gia

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