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A Study of Digital Image Coding and Retrieving Techniques. 數位影像編碼與擷取技術之研究. 指導教授 : 張真誠 教授 研究生 : 周永振 Dept. of Computer Science and Information Engineering, National Chung Cheng University. Outline. Part 1: Compression domain data hiding Part 2: Data hiding using Sudoku

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a study of digital image coding and retrieving techniques

A Study of Digital Image Coding and Retrieving Techniques

數位影像編碼與擷取技術之研究

指導教授: 張真誠 教授

研究生: 周永振

Dept. of Computer Science and Information Engineering, National Chung Cheng University

outline
Outline
  • Part 1: Compression domain data hiding
  • Part 2: Data hiding using Sudoku
  • Part 3: Reversible data hiding for color image
  • Part 4: High payload data embedding for color image
  • Part 5: SOC improvement

Yung-Chen Chou

introduction
Introduction
  • Steganography
    • Secret data delivery
    • Visual quality vs. embedding capacity
    • Categories:
      • Compression domain
      • Spatial domain
      • Frequency domain
    • Grayscale image/color image
  • SOC improvement
    • Indicator
    • Eliminate the indicator

Yung-Chen Chou

introduction cont
Information hiding (Data hiding)Introduction (Cont.)

Hiding system

Stego image

Cover image

1 0 1 0 1 0 0 1 0 1 1 1 1 0 0

Secret message

Yung-Chen Chou

vq domain data hiding
VQ domain data hiding
  • Vector quantization

Yung-Chen Chou

vq domain data hiding cont

d16

d12

d15

d14

d13

VQ domain data hiding (Cont.)
  • Codeword pairing

{d12, d13, d14, d15, d16, d23, d24, d25, d26

d34, d35, d36, d45, d46, d56}

cw6

cw2

cw5

cw4

cw1

cw3

G0

G1

G-1

d36>TH

Yung-Chen Chou

vq domain data hiding cont1

Indicator = ‘0’

Indicator = ‘1’

Encoded by cwi

VQ domain data hiding (Cont.)
  • Data embedding

NBVX = {x0, x1, x3, x4, X, X, X, x8, X, X, X, x12, X, X, X}

Image

If SMD(cwi,NBVX) <SMD(cwj, NBVX) then X is replaceable

Else X is non-replaceable

If secret bit = ‘0’ then encode X by cwi

else encode X by cwj

cwi

cwj

Yung-Chen Chou

G0

G1

vq domain data hiding cont2
VQ domain data hiding (Cont.)
  • Data extracting and restoring

If SMD(cwi) < SMD(cwj) and indicator = ‘0’  restore X by cwi

If SMD(cwi) < SMD(cwj) and indicator = ‘1’  restore X by cwj

If SMD(cwi)  SMD(cwj) and indicator = ‘0’  restore X by cwj

If SMD(cwi)  SMD(cwj) and indicator = ‘1’  restore X by cwi

Image

If X encoded by cwithen secret bit = ‘0’

If X encoded by cwjthen secret bit = ‘1’

cwi

cwj

Yung-Chen Chou

G0

G1

vq domain data hiding cont3
VQ domain data hiding (Cont.)
  • Experimental results

Yung-Chen Chou

vq domain data hiding cont4
VQ domain data hiding (Cont.)
  • Experimental results

Yung-Chen Chou

data hiding using sudoku
Data hiding using Sudoku
  • Spatial domain data embedding
  • Sudoku
    • A logic-based number placement puzzle

Yung-Chen Chou

data hiding using sudoku cont
Data hiding using Sudoku (Cont.)
  • A Sudoku grid contains nine 3 × 3 matrices, each contains different digits from 1 to 9.
  • Each row and each column of a Sudoku grid also contain different digits from 1 to 9.
  • Property

Possible solutions:

6,670,903,752,021,072,936,960

(i.e. ≈ 6.671×1021)

Yung-Chen Chou

data hiding using sudoku cont review zhang and wang s method embedding
Data hiding using Sudoku (Cont.) Review Zhang and Wang’s method(Embedding)

Extracting function:

Secret data:1000 1011…

p2

255

0

1

2

3

4

0

1

2

3

4

0

1

10002

1 35

:

:

:

:

:

:

:

:

:

:

:

:

:

11

2

3

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0

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4

0

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3

2

10

0

1

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0

1

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0

1

0

Cover image

9

3

4

0

1

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4

0

1

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3

8

1

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0

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0

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1

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7

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0

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6

2

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3

1

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0

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0

0

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0

1

2

3

4

0

1

0

Stego image

p1

0

1

2

3

4

5

6

7

8

9

10

11

255

Magic Matrix

Yung-Chen Chou

data hiding using sudoku cont review zhang and wang s method extracting

135

Extracted secret data: 10002

Data hiding using Sudoku (Cont.) Review Zhang and Wang’s method(Extracting)

p2

255

0

1

2

3

4

0

1

2

3

4

0

1

:

:

:

:

:

:

:

:

:

:

:

:

:

11

2

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0

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4

0

1

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3

2

10

0

1

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0

1

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0

1

0

9

3

4

0

1

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3

4

0

1

2

3

4

3

8

1

2

3

4

0

1

2

3

4

0

1

2

1

Stego image

7

4

0

1

2

3

4

0

1

2

3

4

0

4

6

2

3

4

0

1

2

3

4

0

1

2

3

2

5

0

1

2

3

4

0

1

2

3

4

0

1

0

4

3

4

0

1

2

3

4

0

1

2

3

4

3

3

1

2

3

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0

1

2

3

4

0

1

2

1

2

4

0

1

2

3

4

0

1

2

3

4

0

4

1

2

3

4

0

1

2

3

4

0

1

2

3

2

0

0

1

2

3

4

0

1

2

3

4

0

1

0

p1

0

1

2

3

4

5

6

7

8

9

10

11

255

Magic Matrix

Yung-Chen Chou

data hiding using sudoku cont1
Data hiding using Sudoku (Cont.)

- 1

Reference Matrix M

Yung-Chen Chou

data hiding using sudoku embedding cont

279

min.

d( , ) = ((8-8)2+(4-7)2)1/2=3

d( , ) = ((9-8)2+(7-7)2)1/2=1

d( , ) = ((6-8)2+(8-7)2)1/2=2.24

9

7

Stego Image

Data hiding using Sudoku (Embedding) (Cont.)

Secret data:011 001 10…

Cover Image

Yung-Chen Chou

data hiding using sudoku embedding cont1

279

d( , ) = ((11-11)2+(15-12)2)1/2=3

d( , ) = ((15-11)2+(12-12)2)1/2=4

d( , ) = ((9-11)2+(14-12)2)1/2=2.83

min.

9

7

9

14

Stego Image

Data hiding using Sudoku (Embedding) (Cont.)

Secret data:011 001 10…

Cover Image

Yung-Chen Chou

data hiding using sudoku extracting cont
Data hiding using Sudoku (Extracting) (Cont.)

Stego Image

Extracted data: 279 = 011 0012

Yung-Chen Chou

experimental results
Experimental results

Yung-Chen Chou

data hiding for color images
Data hiding for color images
  • True color and color palette image
  • Color pixel (Red, Green, Blue)
  • Reversibility

Yung-Chen Chou

data hiding for color images cont

Stego

Data hiding for color images (Cont.)
  • Review Fridrich’s method

R+G+B mod 2 = (115 + 216 + 112) mod 2 = 1

R+G+B mod 2 = (105 + 146 + 193) mod 2 = 0

Image

Secret: 010…

Yung-Chen Chou

data hiding for color images cont1

( R, G, B)

pi = (112, 217, 110)

pi+1=(115, 216, 112)

(115, 216, 112)

(115, 112, 216)

(216, 115, 112)

(216, 112, 115)

(112, 115, 216)

(112, 216, 115)

d0 = 3.74

d1 = 149.23

d2 = 145.68

d3 = 147.87

d4 = 147.11

d5 = 5.1

Sorting

00 01 10 11

d0 < d5 < d4 < d3 < d2 < d1

log2NG = log26 = 2

Data hiding for color images (Cont.)
  • Proposed method (Embedding)

If d0 is first one then embeddable

Else non-embeddable

Image

If d(pi+1, p’i+1) < TH=50 then embed secret

Else non-embeddable

require extra information

Secret: 011…

Stego

Yung-Chen Chou

data hiding for color images cont2

( R, G, B)

(112, 217, 110)

(112, 216, 115)

(112, 216, 115)

(112, 115, 216)

(216, 112, 115)

(216, 115, 112)

(115, 112, 216)

(115, 216, 112)

d0 = 5.1

d1 = 147.11

d2 = 147.87

d3 = 145.68

d4 = 149.23

d5 = 3.74

Sorting

00 01 10 11

d5 < d0 < d3 < d1 < d2 < d4

log2NG = log26 = 2

Extracted data: 01

Data hiding for color images (Cont.)
  • Proposed method (Extracting and restoring)

Stego

Restored image

Yung-Chen Chou

data hiding for color images cont3
Data hiding for color images (Cont.)
  • Experimental results

Yung-Chen Chou

data hiding for color images cont4
Data hiding for color images (Cont.)
  • Experimental results

Yung-Chen Chou

high payload data hiding for color images

c1 >c2, if (v1>v2) or

(v1=v2 and r1>r2) or

(v1 = v2 and r1=r2 and g1>g2)

c1 = c2, if (r1=r2 and g1=g2 and g1=g2)

c1 < c2, otherwise

0

1

0

1

0

c1

c2

c3

c4

c

High payload data hiding for color images
  • Review Tzeng’s method

v = 0.3 r + 0.59 g + 0.11 b

v1 = 0.3 10+0.59 20+0.11 15 = 16.45

v2 = 8.17

v3 = 10.22

v4 = 15.21

vc = 18.17

Image

Secret: 101…

Yung-Chen Chou

high payload data hiding for color images cont

8

6

8

15

6

15

14

16

6

8

15

14

16

14+1=15

15

20

16

20

10

10

10+6 =16

Stego

High payload data hiding for color images (Cont.)
  • The proposed (Embedding)

 log2(8-6)=1

Image

 log2(20-10)=3

Secret: 11010010100…

Yung-Chen Chou

high payload data hiding for color images cont1

8

15

6

16

20

10

6

8

15

14

16

14-15=1=12

 log2(20-10)=3

16-10 = 6 = 1102

1

110

Stego

High payload data hiding for color images (Cont.)
  • The proposed (Extracting)

 log2(8-6)=1

Extracted secret:

Yung-Chen Chou

high payload data hiding for color images cont2
High payload data hiding for color images (Cont.)
  • Experimental results

Yung-Chen Chou

soc improvement

0

0

52

52

1

1

53

53

2

2

49

49

3

3

50

50

4

4

57

57

5

5

55

55

6

6

48

48

7

7

47

47

State codebook

Index table

State codebook

SOC improvement
  • Scan-order coding (SOC)

Indicator

Compression code: …1 011…

Index table

Indicator

Compression code: …0 01100010…

Yung-Chen Chou

soc improvement cont

α

Secret = 0

If SMD(α, NBVB) <SMD(α, NBVB)

Secret = 1

α

Secret = 0

000 ||α

If SMD(α, NBVB) SMD(α, NBVB)

111 || α

Secret = 1

SOC improvement (Cont.)
  • Review Lin and Chang’s method

NBVB = {b0, b1, b3, b4, X, X, X, b8, X, X, X, b12, X, X, X}

Yung-Chen Chou

soc improvement cont1

Can be compressed by

SOC (i.e. indicator = 1)

Sorted SCB

Index table

For indicator = 1

Sorted SCB

For indicator = 0

SOC improvement (Cont.)
  • The proposed method (Encoding)

Index table

If SMD(cw50, NBVBi) < SMD(cw55, NBVBi)

Compression code: …101

Else Compression code: … 111 010

Yung-Chen Chou

soc improvement cont2

Index table

For indicator = 1

For indicator = 0

For indicator = 1

Sorted SCB

For indicator = 0

SOC improvement (Cont.)

Can be compressed by

SOC (i.e. indicator = 1)

Index table

If SMD(cw130, NBVBi) < SMD(cw3, NBVBi)

Compression code: … 10000010

Else Compression code: … 11111111 10000010

Yung-Chen Chou

soc improvement cont3

Using cw50 to decode Bi

For indicator = 1

Sorted SCB

For indicator = 0

SOC improvement (Cont.)
  • The proposed method (Decoding)

Compression code: …101…

The indicator for next block is ‘1’

SMD(cw55, NBVBi) SMD(cw50, NBVBi)

Index table

Yung-Chen Chou

soc improvement cont4

Using cw50 to decode Bi

For indicator = 1

Sorted SCB

For indicator = 0

SOC improvement (Cont.)

Compression code: …111 010…

The indicator for next block is ‘1’

Index table

Yung-Chen Chou

soc improvement cont6
SOC improvement (Cont.)
  • Experimental results
conclusions
Conclusions
  • Steganography
    • Achieve high payload data embedding
    • Reversibility
  • Achieve high payload data embedding for color images
  • Success eliminate the indicator of SOC

Yung-Chen Chou