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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.