Xây dựng lược đồ thủy vân bền vững khóa công khai sử dụng kỹ thuật trải phổ trên miền tần số (Luận văn thạc sĩ)

i
IH
IH C

NGUY N TR

C

TH

N V NG

D NG K THU T
TR I PH

NT NS

LU

KHOA H C

- 2016
S

c li u


ii
IH
IH

NGUY N TR

C

TH

N V NG

D NG K THU T
TR I PH

NT NS
Khoa h
: 60 48 01 01

ng d n khoa h c: PGS.TS. PH

- 2016

S

c li u

T


iii

L
t qu

lu

u,

ng t ki n th c
is

ng d n t

c

trong

m th c ti n c a b

a th

t. Nh ng

t trong lu

mb tc

ts h
tham kh

t Vi t Nam. T t c

tx

nh
um

qu

c k lu t theo

nh cho l
lu

S

u

c li u


iv

L IC

L

n

Hi

ih
ng d y

ng ki n th c r t b

trong th i gian h
h

n t ng tri th

ph c v

u khoa

.
c bi

s

-TS. Ph

n th y
ng d n, ch b

Xin g i l i c
ct
.

S

c li u

v

M CL C
L

.................................................................................................................iii

L IC

.......................................................................................................................iv

M C L C .............................................................................................................................v
...............................................................................................vii
.....................................................................................................viii
M

U ...............................................................................................................................1
: T NG QUAN V

NH S , GI

......................3

1.1. nh s .............................................................................................................. 3
m nh s ............................................................................................3
i nh s .............................................................................................3
1.1.3. M t s

m nh ......................................................4

1.1.4. Histogram c a nh..........................................................................................5
nh d ng

nh Jpeg ................................................................5

1.1.6. M t s

........................................................................................8

1.2. K thu t gi u tin ............................................................................................ 10
m gi u tin.........................................................................................10
thu t gi u tin ..............................................................................10
thu t gi u tin trong nh ....................................................................12
1.2.4. M t s thu
Thu

nh nh

..............................................14

......................................................................................................21

1.3. K thu t th

.......................................................................................... 23

m th

.......................................................................................23

1.3.2. Th

......................................23
thu t th
th ng thu

....................................................................24
............................................................................25

t c a h thu
1.3.6. Nh ng t

.......................................................................27

n h thu

..................................................................28

ng nh trong thu

S

c li u

......................................................29


vi
c v i th
1.3.9.

ng d ng c a th

c...............................................31

.............................................................................32

: TH

NV

2.1. M t s

N T N S ..34

th

n t n s .................................................... 34

2.2. M t s thu

nv

n Cosine r i

r c (DCT). ............................................................................................................ 35
2

n

i DCT........................................................................................35

i DCT 1 - D ........................................................................................36
i IDCT 1 - D .......................................................................................36
i DCT 2 - D ........................................................................................37
i IDCT 2 - D .......................................................................................38
2.2.2. Mi n DCT......................................................................................................39

2.3. Thu

................................................... 39

2.3.1. Thu

.......................................................................................39

2.3.2. Thu

..........................................................................................42

n v ng c a thu
:

3.1. Th

......... 45
NGHI M ............................................................48

n quy

..................................................................... 48

...........................................................................................48
...........................................................................................48
ng gi i quy

..............................................................................49

3.2. Ph n m m th nghi m th

nv

n DCT........................ 49

3.2.1. Giao di

................................................................49

3.2.2 Th nghi m ....................................................................................................51
.................................................................................55
K T LU N..........................................................................................................................59
U THAM KH O ...................................................................................................61

S

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vii

CPT: Y.Chen, H.Pan, Y.Tseng

S

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viii

u di

m nh trong nh s ................................................ 4
histogram c a

................................... 5

p nh bitmap .................................................................... 6
............................................................................ 8
........................................................................ 9
c

u tin ........................................................ 11

gi

u ................................................................. 12
thu t thu

...................................................... 24
.................................................. 26

nh thu

............................. 27

.............................................................. 39
n th c hi

............................................... 51

nh th nghi m ........................................................................ 53
..................... 54
s

S

......... 55

nh b n quy

v

nh ............ 56

nh b n quy

v

u nh .... 57

nh b n quy

v

nh ............ 57

c li u


1

M

U

Hi n nay m

n truy n

t i, chia s

um

m

n ti n, hi u qu . T t c m

tv

ki

i

k tn

in c n thi t m
p s n ph

n ph m c

cung c p d li

n ph

c qu
c do n

h

m b n quy

t

y c n thi t ph

gi

h n ch vi c vi ph m b n quy

li u s . M t trong nh ng gi
th y

u hi

n ph m d

b o v b n quy

thu t

.
Th

d

t qu

u c a nhi

c, k thu t gi

t th

us .

M

cg i
n ph m s . D

th

d
m th

d v . Th

v

c ng d

d li u s

n
nv

v b n quy
G

iv

nv

c ng d ng trong

o

n ph m s .
ts

c v th

b nv
m

d ng chung m
n vi c b o m
u th

kh c ph c v

u th
ts

p ph i nh
u chuy

nv
S

i

u
i

c li u


2

d

d
um

d ng trong th c ti
th
s

u ng

y em ch

nv

ng
s d ng k thu t tr i ph

. N i dung lu

nt n

u m t s k thu t gi u

tin, nh s

nv

th

c

nh s

n v ng k

ts

c

ng d ng bi

i Cosine r i r c (

u, ph n k t lu n, ph n m c l

u tham kh o.

DCT).
C

a lu
nm

Lu

cb c cg

th

ng quan v

nh s , gi

.

nv

nt ns
nghi m.

- K t lu

ng ki n ngh v

n.

M
l

tn
g ng.

, do th i gi

n ch

i nh ng thi

cs

b oc

lu
ng c

S

c li u

n, ch


3

T NG QUAN V

NH S , GI

TH

1.1. nh s
m nh s
nh s
(pixel), m

p h p bao g m h u h
m

nt

cg

c bi u di n b i m t s h u h

ng t t

nh s

c

y d li u nh s

m

x p x b ng nhau.
c, nh s

t ma tr n

t, m i ph n t c a ma tr
m

m nh

m

xem vi c x

nh s

i di n cho

vi c x

n

i nh s
D

chia nh s

n:

nh nh

(true color).
nh nh
nh nh

nh ch

i di

ng c a nh. N

nh

y, nh nh

t ma tr n nh

nh n t
trong kho

-

tr

ng.

y,

t

bi u di

m nh trong
a nh t

m
i di n c
S

c bi u di n b i m t s byte
c

c li u


4

g

nh true color.

ng v i 3
m nh. H

bao g m 3 ma tr

ng v

c s d ng

ph bi n nh t.
i:

ns

n s th p.
1.1.3. M t s

m nh

m nh
m
d

t ph n t
m

nh t trong m t nh
cg

Bi u di
am
M

.

m nh trong nh s

m nh (Neighbors of a Pixel)

m nh p trong h t

chi u d

nh theo

u ngang v i t

(x - 1, y); (x, y + 1);

(x, y - 1)
T ph pb
m nh

m

cg

u N4(p). Kho

b ng m

-

a

b

kho
ng h p p n m

n m

nh.
S

c li u

a nh, m t s

aps


5

1.1.4. Histogram c a nh

ng th
m

n su

iv i

am

m

nh

c:
Y = 0.299R + 0.587G + 0.114B
Trong

:

-Y

a nh.

-

.
: Ta

c bi

histogram c a

Lena.bmp
histogram c a
nh d ng nh bitmap

nh Jpeg

nh bitmap
-

nh bitmap

bitmap

nh d

S

c bi

n v
bi n

c li u

ng a
h

Windows

p nh


6

i d ng bitmap

.BMP ho c .DIB (Device

Independent Bitmap).
-

n c a m t t p nh bitmap:

+S

m

2n

n-

n

u b i n. M t nh bitmap

nh

n=1

sau:

ng

n=4
n=8

u\

n = 16
n = 24

nh 16 tri
24

v y

nh trung th c nh t.

+ Chi u cao c a nh cho b
+ Chi u r ng c a nh cho b i
-C

m nh.
m nh

p tin nh BMP bao g m 4 ph n:

p nh bitmap
Bitmap Header (14 bytes): ch

ta nh n d ng t p tin

bitmap.
ts

Bitmap Information
hi n th nh.
S

c li u

ta


7

Color Palette (4*x bytes v i
s

a nh)

c s d ng trong nh.
li u nh.

Bitmap Data:

mn ib
ng b t k thu
ghi tr c ti

t
yk

p tin. M i

m

m nh s

c

b i m t hay nhi u byte

nc a

i d ng BMP

r t l n, g p nhi u l n so v

ng h n

GIF, JPEG hay PNG).
nh JPEG
-

nh d ng

nh, thu

JPEG (Joint Photographic Experts Group) - m t trong
nh

nh hi u qu
nh sau khi gi

l

s

b suy gi m sau khi gi

i

c l n.

u. Ch

suy gi

m

ng nh s

n theo h s
ch p nh

nh

n thi

c am

nh t

c lo i b

c d

u v h

i.

-

ts

+

ng nh

m sau:
bi

tb

trang web.
+

hi n th

colour

nh v

true-

b m

i nh g c.

n 16 tri

+ nh s d ng thu
ts

ng bao gi

xu t hi

m

S

c li u

mm


8

1.1.6. M t s

hai

.

T

nhau

S

c li u


9

u YCbCr

th

S

c li u


10

trong
:

Y = 0.299R + 0.587G + 0.114B
Cb = - 0.1687R 0.3313G + 0.5B +128
Cr = 0.5R -0.4187G 0.0813B + 128
1.2. K thu t gi u tin
m gi u tin
Gi

t k thu t gi u m

t

ng d li
Khi gi u tin ta ph
li

mb

c hai m

ng th

gi u tin

ib ov

m

ng th nh

o m t cho d

c

i ta chia gi

ng.

u tin m t, nh m t

thu t gi u tin sao

ch
ng th

ng thu
u nhi

thu

n ng d ng l n
ct

t nhi u k

xu t.
thu t gi u tin
u tin:
-

n ch a bao g

ng

gi

n (Multimedia).
-

n gi

tu thu

i s d ng.

-B

gi

hi n v i m

t gi

gi

ng ch a nh m t b
S

m

c li u

c th c
c


11

-

ng sau khi gi u tin ta

li

c gi u tin s

c. D
ti n truy n

c th hi
n gi u
D li u

D li u

ng
(audio,
video,
nh....)

ng
c

gi u tin

B

6

-

c

u tin

u tin.

- B gi

ng v i b

-

gi

- K t qu
Tu

gi ng ho

cg

ng g

ng h

i

c gi u.
c nx

v

li u m

ch a tin gi

bi

t

li
c th hi

S

c li u

ng


12

D li u

D li u

ng
(audio,
video,
nh....)

ng
B gi i

c
gi u tin

u

Ki

7

gi

V i m t h th ng gi u tin m

nh

u
a d li u c n gi u

c bi t. M t h th

b o m t cao n u

ph c t p c

th c hi
t s h th ng l
c gi u, ho

ns

ns
ng c

t

ng ch a d li u.
1.2.3.

k thu t gi u tin trong nh
Gi

nh

Mi

n d li u nh g

gian

m
ng ti p c n t

m

n vi c gi u tin trong nh
n vi

S

tr c ti p c

c li u

m nh ngu n, m t


13

bi n c

ng ti p c

ng c a m

n

m nh.
u h n ch , ch ng h

mb

n v ng c

bi

iv

nh ho

hi

i b ho

ng nh t c a m i

m nh.
Gi

n bi

Gi

i nh
ng gian

n

th ng r i r c m

r ir cc

m nh g

trong nhi
nh

ng h

nh ho c r t ph c t

c ti

n bi n s

cl pt

c ti

p ph i nh

u qu
c ti

o

thu t bi
chuy n mi n bi n s
th ng r i r c s

cl

i

c bi u di

nm iv

Mi n bi
i mi n

mv

nt ns

n s m i.
n nh

c khi bi n

thu t s d
i h t

nh m chuy n mi
mi

n t n s , c th

r ir cc

m nh sang mi n m

M

n s m i.

ng thu n l

ng h p c th

l a ch

p. Sau khi bi n
r i r c trong mi n bi n s m

thi

cl

S

c li u

nh v mi n bi n s

uc n
c l p.


14

n r t nhi
g p ph
l

c

i tr c ti p trong mi n bi n s
ts

c

i ph bi n hi

r ir

i
thu t x

c s d ng ph bi n

c bi t trong x

nh s

c gi u tin, th
1.2.4. M t s thu

.

nh nh
-Lee [7]

Thu
Thu t

n

c a

gi M.Y. Wu

ng cho

J.H.Lee gi

n

ng.
: chia nh g

ng c a thu

i nh , trong

m i kh i s gi u 1 bit ( b = 0 ho c b = 1)
i nh g c F,

m t
c

nh

m t ma tr n nh
F. Sau q

m ts
Thu t

c
c

hi u ch nh.

gi u tin.
u tin:
u Bm*n

n nh

Input:
- Kh i nh g c F

B m*n

-

B m*n

tK

-

t)

n gi u ( b=0 ho c b=1)

Output:
N u thu
(G

B m*n

c hi

t qu

it

t ph n t t ma tr

c bi

nG

ch t sau:
+ 0< SUM(G
S

K) < SUM(K)

c li u

(1.1)


15

+ SUM(G

K) mod 2 = b

(1.2)

N i dung thu
c 1:

t s = SUM(F

K)

ng h p sau:
ng h p 1
N u s = 0 ho
tG=F
K
ng h p 2
N

c2
c 2:

ng h p sau.

ng h p 1:
N
G=F
K
ng h p 2
N u s mod 2

c 3.
ng h p

ng h p 1
N u s = SUM(K) Ch n ng

n t (i,j) th

Fi,j = 0
G=F
ng h p 2:
N
Ch n ng

S

n t (i,j) th

c li u

i,j

i,j =

0


16

Fi,j = 1
G=F
ng h p 3:
N us>1

-

Ch n ng

n t (i,j) th

i,j =

1

Fi,j = 1 - Fi,j
G=F
Cu

th

i nh Gi

c

b1, b2, ..., bn
tin.

.

0.
Nh
Th nh t:
ch n k
gi

th c hi n gi
um t

c

m tr ng (ho

l bit

c s r t th p.
Th

i ma tr n

t ph n t (t

m nh F thu

ct

bi

it

y n u ch

l n

nh n bi t b ng m
gi u c a thu

i gi

Th ba: Khi c n bi

.
i ma tr n F, thu

m t ph n t Fi,j ng v i Ki,j=1. Do v y, trong m t s
S

c li u

i ng
ng h p nh sau khi

17

c gi u tin s xu t hi n nh

t so v i nh g

c b ng m

u cho thu

n ph n t

ng theo m
[8]

Thu
Thu

Chen - Pan

gi u tin, k thu t gi u tin CPT nh
c

c

c nhi u s
vi

lu

ts

c thu n l
c s d ng trong k thu t CPT.

.
n nh
uC=A

uA

B v i Cij = 1 n u Aij Bij

minh ho

ij

= 0 n u Aij= Bij

th c hi

2. SUM(G

c

n nh

K)

n:

T=F

G

V i Ti, j = Fi, j

Gi, j
.

Ma tr

cg

n tr ng s c p r v i

n u m i W tho
2 r - 1}

{Wi, j

S

c li u

u ki n: