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A hierarchical digital watermarking method for image tamper detection and recovery

Source: Pattern Recognition, Vol. 38, Issue 11,

December 2005, pp. 2519-2529

Author: Phen-Lan Lin, Chung-Kai Hsieh, Po-Whei

Huang

Speaker: Yi-Hsuan Fan

Date: 2005/10/06

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Outline

Introduction Proposed method

Preparation Watermark embedding Hierarchical tamper detection Tampered image recovery

Experimental results Conclusion

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Introduction

received image

delivered image

4

Preparation

4 13

1 6

10

5 15

3

2 8 11

12

9 14

7 167 1

49 1

2

11

16

5 2

13

1 15

8

3 6 10

4

1 2 9 10

3 4 11 12

5 6 13 14

7 8 15 16Torus

automorphism

block 1 mapping sequence : 1, …, 3, …, 10, …, 1

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Watermark embedding (1/2)

1 2 9 10

3 4 11

12

5 6 13

14

7 8 15

16

1 2 9 10

3 4 11

12

5 6 13

14

7 8 15

16

avg_B=(I1+I2+…+I16)/16

avg_Bs=(I1+I2+I3+I4)/4

block B

block A

avg_As=(I1+I2+I3+I4)/4

a1 a2

a3 a4 a5 a6 a7

a8

r

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Watermark embedding (2/2)

69 78 82 97

35 46 210

102

51 33 73 44

173

83 145

126

104

22 99 207

39 55 61 132

42 66 3 23

227

198

145

164

0 1 1 0 1 0

0 0 0 1 0 1

0 0 1 0 0 1

0 0 1 1 0 1

Example :

block A

block B

avg_As=(69+78+35+46)/4=57=00111001

avg_Bs=(104+20+36+52)/4=53=00110101avg_B=(104+20+96+204+…+164)/16=97

r=001110

v=0, p=0

104

22

39

55

0 0

0 0

1 1

1 0

104

20

39

54

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Hierarchical tamper detection (1/2)

104

22 99 207

39 55 61 132

42 66 3 23

227

198

145

164

Level 1 :

Level 2 :

avg_Bs=(104+20+36+52)/4=53=00110101

avg_B=(104+20+96+204+…+164)/16=97

104

22 99 207

39 55 61 132

42 66 3 23

227

198

145

164

v’=0, p’=0 v=0, p=0

Level 3 :

Error B Error

Error Error Error

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Hierarchical tamper detection (2/2)

Level 4 :

104

20 99 207

39 54 61 132

42 66 3 23

227

198

145

164

0 1 1 0 1 0 0 0

0 0 0 1 0 1 0 0

0 0 1 0 0 1 1 1

0 0 1 1 0 1 1 0

r=001110(00)=56=avg_Bs

block B

69 78 82 97

35 46 210

102

51 33 73 44

173

83 145

126block A

avg_As=(69+78+35+46)/4=57

avg_Bs avg_As

57=00111001=00111000=56

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Tampered image recovery

69 78 82 97

35 46 210

102

51 33 73 44

173

83 145

126

104

20 99 207

39 54 61 132

42 66 3 23

227

198

145

164

0 1 1 0 1 0 0 0

0 0 0 1 0 1 0 0

0 0 1 0 0 1 1 1

0 0 1 1 0 1 1 0

block B

56 56 82 97

56 56 210

102

51 33 73 44

173

83 145

126

r=001110(00)=56

tamped block A recovered block A

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Experimental results (1/4)

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Experimental results (2/4)

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Experimental results (3/4)

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Experimental results (4/4)

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Conclusion

A efficient and effective digital watermarking method for image tamper detection and recovery.