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BỘ GIÁO DỤC VÀ ĐÀO TẠO...............................................................................10
TÌM HIỂU BÀI TOÁN NHẬN DẠNG BIỂN SỐ XE................................10

ĐỒ ÁN TỐT NGHIỆP ĐẠI HỌC HỆ CHÍNH QUY.............................................10
Ngành: Công nghệ thông tin....................................................................................10
BỘ GIÁO DỤC VÀ ĐÀO TẠO...............................................................................11
TÌM HIỂU BÀI TOÁN NHẬN DẠNG BIỂN SỐ XE................................11
PHẦN GIỚI THIỆU.................................................................................................14
Chương 1:.......................................................................................................15
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Z!Ž<5cg)28f/)*.^
.*:\5›|*()'f*,)'}
Z0Ž/99/
Z ŽJ=):7
Z[Ž1l5`y)'
ZeŽ`(/)*
ZIŽ/)**:R)
ZiŽv)**:R)
ZZŽ†)**z5
Z"Ž>)'&3)
"!Ž(97
" Ž$:Q)'97
"[Žv)**>?5
"eŽ65/3:
"IŽR:/9)'
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"ZŽŒ5/9)'
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œ}Những quy định về màu sắc và chữ số đặc biệt:
1. Màu xanh chữ trắng là biển xe của các cơ quan hành chính sự nghiệp:
Ž`45.*:\55*m)*_*x.*vO(S/T)M9)*Z!
0Z

Ž<5.—)*.*()*.*v.*U=GH.>g)'W)'
2. Màu đỏ chữ trắng là biển xe trong quân đội:
™+/)*c=()0 
™+$:Y)=()eu/)*c=()5N:O=)'
+S\S/)*
+/)*5*x)',)'/)*
+/)*5*x)'*=<*n5
1+/)*c=()`>‚)'1g)
+/)*5*x)'.*,)'./)O/3)O65
+\.>O-)*S/3)_*b)'
+n52/-)OX5K:Y)
+n52/-)K:Y)]
J™+$:Y)f*:0
J+$:Y)f*: 
J+$:Y)f*:[
J+$:Y)f*:e
J+$:Y)f*:I
J+$:Y)f*:j
JJ+$:Y)f*:"
+<5K:Y)]2/-)
$+$:Y)5*x)'*Q/K:Y)
$Ju$+$:Y)5*x)'_*b)'f*,)'f*,)'K:Y)
+d)'5X55*m)*.`8
+d)'5X5*R:5q)
J+d)'5X55,)')'*/-_K:H5_*b)'
+d)'5X5fk.*:R.
E+\.d)'.*977>:
+/U..UO
3. Màu trắng 2 chữ, 5 số là biển dành cho người nước ngoài:
ŽO(MU)'=6/'/9=

0"
ŽO(MU5x95<5.d5*W5u5<)*Y))>?5)'=(/+`=)'cl[GH•'/€9O(
7FK:H5'/9u GH./^_.*U=O(GH.*W.4B
œpUGHZ!MMMŽ]]O(S/T)5w_5*=5<5c6/GWK:<)u.*37'65*c••
'/€92( GH5:H/O(!0O(S/T)MU5x9.d)'OF)*G4
4. Những xe mang biển 80 gồm có :
Ž<59)5x9`:)'>g)'Q)'
Žy)_*b)'*x.85*)>?5
Žy)_*b)'$:H5*\/
Žy)_*b)'*m)*_*x
Ž\,)'9)
ŽpU_*X52X5<5c‹)'5*m:;2/3)`:)'>g)'Q)'5,)'.<5.6/(\/
2(5<5.*()*2/3)*m)*_*x
Ž\)'=6/'/9=
Ž/-)f/T7G=<.)*Y)@Y).H/59=
Ž=(<))*Y)@Y).H/59=
Ž(/.`:]L)*v)*/-.97
Ž(/./^)')l//-.97
Ž*,)'.w)MF/-.97
Ž<=)*Y)@Y)
Ž*9)*.`9*()>?5
Žn52/-)*m)*.`8K:H5'/9
Ž9)K:Q)OPy)'uQ=.()'uf*:/.m5*O85*GN‹*mE/)*ž
Ž`:)'.Y7O>:.`€K:H5'/9
Ž%;S9)Y)GHf^*=65**=<'/9cv)*
Žd)'5,)'.]q:f*m/-.97
Ž<5c6/GWK:<)u.d5*W5K:H5.^2()*Y)2/3))'>‚/)>?5)'=(/
Ž%;S9)*W)'f*=<)*()>?5
ŽX5()'f*,)'@Y)@X)'/-.97
ŽJ/T7.=<))*()>?5

!
5. Các biển A+
pU5x9,)'™)ŽQ)*1<..>g)'W)'2?/5<5.—)*
2m@X+[0™ŸMU5x9,)'™)ŽQ)*1<..*()*_*H(\/
1.3. Một số hướng giải quyết bài toán nhận dạng biển số xe:
l`w.)*/L:_*>g)'_*<_./^_5R)B`=)'cl5l*9/5<5*./^_5R)_*dS/^)
@>?/cY]+
1.3.1. Hướng tiếp cận phát triển vùng:
• *l7.<5'/Q/'UO›*].U9)@™@`/U)J/U`)9)c>t5c6/@/-)5*=5<5*
./^_ 
5R))(]
• .>•)'5x9_*>g)'_*<_)(]+clO(S/T)GHMU.*>‚)'5*W97\.7(:
c‹)')*w.u5*o)'*6)7(:.`Œ)'u2(5l@/-).m5*.>g)'cH/)*w.c8)*Bv2R]5l
.*T@a)'_*>g)'_*<__*<..`/T)2a)'u*=~5GN@X)'f*:)'5*€)*R.@/5*:]T)
.`=)'cT.v7`92a)'5l.m)*5*w..*•97F)S/T)GHMU2(./^)*()*)*R)@6)'B
• :c/T7+`w.cg)'/Q)u2(MNOP`w.)*9)*cH/2?/)*€)'Q)*5*—5*W9
2a)'S/T)GHMUB
• *>t5c/T7+f*/Q)*5l.*37)*/L:cH/.>t)'f*,)'_*Q/O(2a)'S/T)
GHMUu5*o)'*6)O(Q)*5*X_.d)'K:<.'‹75Q5Q)*2R.S3))'=(/.*v5<5*./^_
5R))(].`•)3)f*,)'*/-:K:QBv2R]_*>g)'_*<_)(]`w.*/-:K:QcH/2?/*-
.*H)'.`67.*:_*mu.`67'<55d)'u'N/MU.4c\)'
1.3.2. Hướng tiếp cận dò biên và biến đổi Hough:
• *l7.<5'/QE/5*9UO/@U)S9:7u=GU)™OUM9)@U`u/5*/f1U`'U]u
19)@OU`=79)c>t5c6/@/-)5*=5<5*./^_5R))(]B
• .>•)'5x95<5*./^_5R))(]O(+/T)GHMUc>t5S9=S=5S•/c>‚)'
2/L)B=clu5l.*T@a)'_*>g)'_*<__*<.*/-)S/3)uG9:cl@a)'_*¡_S/^)cd/
=:'*cT.`m5*)*€)'c=6).*o)'@n5u)'9)'.‹).6/.`=)'Q)*B/9=c/T75x9
)*€)'c=6).*o)')(]5*m)*O(2a)'S9=5*W9S/T)GHMUB(5:H/5a)'O(./^)
*()*)*R)@6)'5<5fP.4•.`3)7¢/2a)'5=)B
• :c/T7+c\5*m)*M<559=B(5<5*-.*H)')*R)@6)'c9_*q)cL:

_*<..`/T).*U=*>?)'./^_5R))(]B
0
• *>t5c/T7+\_*W5.6_.m)*.=<)f*<59=BJ*/Q)*5l.*37)*/3:
cH/.>t)'f*<5.*vf*H/O>t)'.m)*.=<).y)'O3)`w.)*/L:B=7X5cm5*O(_*Q/
M<5c8)*c>t52a)'5=))(=5*W9S/T)GHMUB
'=(/*9/5<5*./^_5R).`3)u5b)5l)*/L:5<5*./^_5R)f*<5cTM<5c8)*
5*m)*M<52a)')(=5*W9S/T)GHMU2(S>?55:H/5a)'O(./^)*()*)*R)@6)'
fP.4BE¢/5<5*./^_5R)5l7\.>:2()*>t5c/T7B9GH5<5W)'@X)'cL:GN
@X)'5<5*./^_5R)S/^)cd/=:'*B`=)'S<=5<=cL.(/5x9U7uU7M/).`v)*S(]
5<5*./^_5R)=:'*B
1.4 Hướng giải quyết:
£_*q)0B[5*z)'.9cF.v7*/T: *>?)''/Q/K:]^.5*=2/-5M<5c/)*
2a)'5*W9S/T)GHMUBE¢/5<5*'/Q/K:]^.5l)*€)'>:c/T72(*6)5*^`/3)'
5x9)lB
*) Một số đặc điểm về biển số xe ở Việt Nam:
• /3:5*:¤)2Lfm5*.*>?5+£7¢/)>?5.*>‚)'5l./3:5*:¤)2Lfm5*
.*>?5)*w.c8)*BH/2?/)>?5.9uS/T)GHMUK:/c8)*f*<c‹)'cL:5*=7¢/O=6/
MUu.;O-5*/L:@(/u`\)'5*=7¢/O=6/MUO()*>)*9:BH/2?/O=6/MU5l7\.
*()'fP.4.*v.—O-@(/r`\)'O(+
IBerIB[
≤≤
HW
BH/2?/O=6/MU5l*9/*()'fP
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eB0rZB!
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O/3).*,)'5=)B=clu5*z)'.95l.*Tc^72a)'O/3).*,)'5=).*•97F).m)*
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)*R)@6)'+GN@X)'_*>g)'_*<__*<.*/-)S/3)2(S/^)cd/=:'*B19:cluGN
@X)'*9/.m)*5*w..`3)S/T)GHMUcTM<5c8)*5*m)*M<52a)'5=)5*W9S/T)GH
MUBJ*/cFM<5c8)*5*m)*M<52a)'5=)5*W9S/T)GHMU.*v./^)*()*)*R)@6)'
5<5fP.4B
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S(][S>?5)*>G9:+
• >?50+)*2(=Q)*7W5M<7|Mu]}.*45*/-).*U=_*>g)'_*<_@b
S/3)2(S/^)cd/=:'*cT.v7`95<52a)'5=)5lf*Q)y)'5*W9S/T)GHMUBn/
.R_5=))(]O(
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.*9=.<5c>t57/3:.Q•.`3)clO(./3:5*m.;O-5*/L:@(/2?/5*/T:`\)'2(GHfP
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e
Chương 2:
PHÁT HIỆN VÙNG CHỨA BIỂN SỐ XE
2.1 Một số khái niệm cơ bản:
2.1.1 Tổng quan về ảnh
a. Ảnh và điểm ảnh:
)*O(7Q)'GH.*45*9/5*/L:
( )
nm
I
u
u5lfm5*.*>?5|EM}u.`=)'cl7¢/
'/<.`8

( )
nm
I
u
|.6/7\.c/T7Q)*}uS/T:.*87W5M<75x9Q)*.6/28.`m
( )
nmu
.>g)'
W)'
E\.Q)*O(Q)*)*8_*Y))^:'/<.`8
( )
nm
I
u
S{)'!*=~50B
b. Mức xám:
EW5M<7O(f^.K:QG47F*l9.>g)'W)'7\.5>‚)'c\G9)'5x97¢/
c/T7Q)*2?/7\.'/<.`8GHŽf^.K:Q5x9K:<.`v)*O>t)'*l9B<5*7F*l9f/)*
c/T).*>‚)'@a)'0iu[ uieBEF*l9 Ii7W5O(_*d@X)')*w.@=OP@=fk
.*:R.Bv
Z
Ÿ Iiu)3)2?/ Ii7W5u7¢/_/MUOc>t57F*l9ZS/.B
c. Đối tượng ảnh:
`=)'_*q))(].95*—M¡.2?/Q)*)*8_*Y)u2v7n/Q)*)*8_*Y)cL:5l
.*Tc>92LQ)*)*8_*Y)S{)'5<5fk.*:R._*Y))'>h)'B9fP*/-:ŠO(.R_5<5
c/T72a)'|c/T7cU)}2(
E
O(.R_5<5c/T7)L)|c/T7.`Œ)'}B9/c/T7
G
2(

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I
u
){7.`=)'Š|*=~5
E
}c>t5'n/O(eO/3).*,)'|ZO/3).*,)'})^:.‹)
.6/7\.@F]5<5c/T7'n/O(c>‚)'c/+
•
( )
!!
u ji
Ÿ
G
2(
( )
nn
ji u
Ÿ
U
•
( )
!!
u ji
( )
00
u ji

→
→
„B
( )
nn
ji u
→
7(
( )
Eji
kk
∈
u
2?/7n/fŸ!u0„u)
•
( )
kk
ji u
O(eO<)''/^)'|ZO<)''/^)'}5x9
( )
00
u
−−
kk
ji
2?/7n/fŸ0u u
„u)
d. 4- Láng giềng và 8- láng giềng:
^:
( )

nmu
O(7\.c/T7Q)*u.*veO<)''/L)'5x9)lO(5<5c/T7•)'9]
S3).`3)u@>?/u_*Q/u2(.`</B9fP*/-:
e
N
O(.R_eO<)''/L)'5x9c/T7
( )
nmu
B
⇒
e
N
( ) ( ) ( ) ( ){ }
0uu0uuu0uu0
+−+−=
nmnmnmnm
>g)'.4.95l.R_ZŽO<)''/L)'
Z
N
I
⇒
Z
N
( ) ( ) ( ) ( ){ }
0u0u0u0u0u0u0u0
e
+−−+−−++∪=
nmnmnmnmN
e. Chu tuyến của ảnh:
Định nghĩa chu tuyến:

*:.:]^)5x97\.cH/.>t)'Q)*
( )
nm
I
u
O(@F]5<5c/T75x9cH/.>t)'+
n
ppp
→→→
BBBB
0!
B19=5*=
0
−
i
p
u
0
+
i
p
O(ZO<)''/L)'5x9
i
p
u
Ip
∉∃
¨
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©

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O<)''/L)'5x9_
/
u2(
n
pp
≡
!
BJ*/cl.9'n/)O(c\@(/*9]5*:2/5x95*:.:]^)B
Chu tuyến đối ngầu:
9/5*:.:]^)Ÿª0u u„u)«2(©Ÿª$0u$ u„u$)«c>t5'n/O(
*9/5*:.:]^)cH/)'A:5x9)*9:)^:2(5*—)^:+
•
ji
∃∀
G9=5*=/2($¬O(ZO<)''/L)'5x9)*9:
• <5c/T7/O(Q)*.*v$¬O()L)2()'>t5O6/B
Chu tuyến trong:
*:.:]^)c>t5'n/O(5*:.:]^).`=)')^:2(5*—)^:+
• *:.:]^)cH/)'A:©5x9)lO(5*:.:]^)5x95<5c/T7)^)B
• \@(/5x95*:.:]^)©)*•*g)c\@(/5x95*:.:]^)
Chu tuyến ngoài:
*:.:]^)c>t5'n/O(5*:.:]^))'=(/)^:2(5*—)^:+
• *:.:]^)cH/)'A:©5x9O(5*:.:]^)5<5c/T7)L)
• \@(/5x95*:.:]^)©O?)*g)c\@(/5x95*:.:]^)
•c8)*)'*†9u.9.*w]5*:.:]^))'=(/5x97\.cH/.>t)'O(7\.c9'/<5
5lc\@(]S{)'7\.S9=K:9)*cH/.>t)'B
2.1.2 Phương pháp tách dò ngưỡng tự động
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gh

+O(.d)'GH7W5M<7'
n/+
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∑
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gi
ihgt
`=)'cl+ ˜1Hc/T7Q)*c>t5M¡.Ÿ7œ)
˜1H7W5M<7c>t5M¡.
n/
( )
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
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!
!
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−−−∗
−
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0Ž'!
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R]G:]`9
θ
O()'>h)'5x9Q)*
2.2 Biên và các phương pháp phát hiện biên.
*) Khái niệm về biên:
/3)O(7\.2w)cL5*x]^:.`=)'_*Y).m5*Q)*2v5<5fk.*:R._*Y)c=6)
Q)*5*x]^:@492(=S/3)BE\.c/T7Q)*5l.*T5=/O(c/T7S/3))^:5lG4.*9]
cd/c\.)'\.2(7W5M<7*9]S/3)O(c/T75l5w_M<75l'/<.`8f*<5*o)5<5
c/T7M:)'K:9)*BR_*t_5<5c/T7S/3).6=.*()*S/3)*9]c>‚)'S9=5x9Q)*
*) Các phương pháp phát hiện biên:
*) Phương pháp tiếp cận theo kiểu cổ điển
Y]O(_*>g)'_*<_@492(=G4S/^).*/3)2L'/<.`8c\G9)'5x9c/T7
Q)*BJk.*:R.5*x]^:@a)'_*<.*/-)S/3)•cY]O(fk.*:R.c6=*(7B^:Ow]
c6=*(7SR5)*w.5x9Q)*.95l_*>g)'_*<_`9@/U).u)^:Ow]c6=*(7SR5*9/
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5X5S\B
2.2.1 Phương pháp gradient
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5l5<5.*()*_*q)S/T:.*8.H5c\.*9]cd/'/<.`85x9c/T7Q)*.*U= *>?)'M2(
]B<5.*()*_*q)5x9`9@/U).c>t5.m)*S•/+
dx
yxfydxxf
fx
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yxf }u|}u|}u|
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.>g)'W)'S•/'
M
u'
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−+=
}u|}0u|
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yxIyxIg
yxIyxIg
y
x
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$:<.`v)*.m)*.=<)c>t5.*45*/-)K:95<5S>?5G9:+
• >?50+m)*
xx
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yy
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yx
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yx
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5*n)`95<5c/T759=.*W u*=~5.*W[BB5*/^7c9GH
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Jk.*:R.)(]GN@X)'*9/7~.)6
0
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y
HI
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x
HI
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•
y
HI
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2.2.2. Kỹ thuật Laplace:
<5_*>g)'_*<_c<)*'/<`9@/U).•.`3)O(72/-5f*<.H.f*/7(c\
G9)'.*9]cd/`•)¡.BJ*/7W5M<7|'/<.`8.6/7\.c/T75x9Q)*}.*9]cd/5*R7u
7/L)5*:]T)./^_.`Q/`\)'u.*v.95l_*>g)'_*<_9_O95U|c6=*(7SR5*9/}5l
*/-:K:Q*g)B=<).N9_O95Uc>t5c8)*)'*†9)*>G9:+

dy
f
dx
f
f
∂
+
∂
=∇
R]G:]`9.95l+
( ) ( )( )
( ) ( )
[ ]
( ) ( )
[ ]
yxfyxfyxfyxf
x
yxfyxf
x
f
x
x
f
u0uuu0
uu0

−−−−+≈
∇
−+∇
≈






∇
∇
∇
∇
=
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0uu u0
−+−+=
yxfyxfyxf
>g)'.4.95l+
( ) ( ) ( )
0uu 0u


−+−+=
∇
∇
yxfyxfyxf

y
f
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*(7SR5 B>?/cY]O([f/T:7~.)6*9]@a)'+
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yxIyxIyxIyxIyxIyxIH
Ÿ|M•0u]•0}Ž|M•0u]}
[!
•|M•0u]•0}Ž|Mu]•0}
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y
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0u00u0
y
yxI
x
yxI
∂
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−
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I

−∇=
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2.3 Phát hiện vùng chứa biển số xe
1gc‹5<5S>?5c>t57,.Q.`=)'*v)*@>?/
)*cq:2(=+O(7\.Q)*5l Ii7W5M<7uc>t5)*8_*Y)*l9.*()*Q)*
)*8_*Y)BEX5cm5*5x9'/9/c=6))*8_*Y)*l9Q)*O()*{7O(7)d/SR.2a)'
S/T)GHMUBJ*/.9.<5*S/3)u2a)'S9=5x9S/T)GHMUGƒ*/-)O3)`•`()'B19:cl
@a)'_*>g)'_*<__*<.*/-)S/3)cT5lc>t5S/3)@n52(=)'9)'5x9Q)*BJ^.
K:Q5x95,)'c=6))(]uQ)*.*:c>t5O(Q)*)*8_*Y)5*—5*W95<556)*@n52(
)'9)'B*45*/-)S/^)cd/=:'*5*=5<5c=6)S/3)2•9Ow]c>t52(M<5c8)*
5<5c=6).*o)'c/K:9.R_5<5c/T7S/3)5x97¢/S/3)uf^.K:QGƒO(5<5c=6)
.*o)')'9)'2(@n5B/9=5x9)*€)'c=6).*o)')(]Gƒ5*=`92a)'5=)
5
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2.3.1. Nhị phân hóa ảnh
)*S9)cq:c>t5GN@X)'O(Q)* Ii7W5M<7B/-5GN@X)'Q)* Ii
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.45*:]T)Q)*7(:.*()*Q)* Ii7W5M<7B:])*/3)u)^:cTQ)* Ii7W5
M<7.*v2/-5_*<.*/-)S/3)f*,)'*/-:K:Qu2vG4.*9]cd/O/3).X55x95<57W5
M<7O(75*=2/-5M<5c8)*S/3)f*,)'_*Q/@s@()'u2(2/-5.v7`95<52a)'O/3)
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5

Hình 2.1: Sơ đồ giải quyết
2=/@/)9`/®Urr*8_*Y)*l9Q)*
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rrq:`9O(Q)*)*8_*Y)
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-=`|/)./Ÿ!ž/ª7ž/••}
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2.3.2 Tách biên:
vS/T)GHMU5l2/L)S9=K:9)*u)3)5*z)'.95q)O(7)d/SR.c>‚)'S/3)
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cm5*5x9'/9/c=6))(]O(.<5*`95<556)*@n52()'9)'cT.v7`92a)'5=)5*W9
S/T)GHMU)*‚.m)*'/9=c/T75x95<556)*@n52()'9)'B£cY]uQ)*cq:2(=O(
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