1. A hierarchical digital watermarking method for image tamper detection and recovery
Source: Pattern Recognition, Vol. 38, Issue 11, December 2005, pp
Author: Phen-Lan Lin, Chung-Kai Hsieh, Po-Whei Huang
Speaker: Yi-Hsuan Fan
Date: 2005/10/06

2. Outline Introduction Proposed method Experimental results Conclusion
Preparation
Watermark embedding
Hierarchical tamper detection
Tampered image recovery
Experimental results
Conclusion

3. Introduction
delivered image
received image

4. Preparation 1 2 9 10 3 4 11 12 5 6 13 14 7 8 15 16 4 13 1 6 10 5 15 3 2 8 11 12 9 14 7 16
Torus automorphism 7 14 9 12 11 16 5 2 13 1 15 8 3 6 10 4
block 1 mapping sequence :
1, …, 3, …, 10, …, 1

5. Watermark embedding (1/2)
avg_As=(I1+I2+I3+I4)/4 1 2 9 10 3 4 11 12 5 6 13 14 7 8 15 16 a1 a2 a3 a4 a5 a6 a7 a8 r
avg_Bs=(I1+I2+I3+I4)/4
block A 1 2 9 10 3 4 11 12 5 6 13 14 7 8 15 16
avg_B=(I1+I2+…+I16)/16
block B

6. Watermark embedding (2/2)
Example :
avg_As=( )/4=57= 69 78 82 97 35 46
210
102 51 33 73 44
173 83
145
126
r=001110
avg_Bs=( )/4=53=
avg_B=( …+164)/16=97
v=0, p=0
block A
104
104
104 22 99
207 39 55 61
132 42 66 3 23
227
198
145
164 1 1 22 20 39 39 55 54
block B

7. Hierarchical tamper detection (1/2)
Level 1 :
avg_Bs=( )/4=53=
104 22 99
207 39 55 61
132 42 66 3 23
227
198
145
164
avg_B=( …+164)/16=97
v’=0, p’=0  v=0, p=0
Level 2 :
Level 3 :
Error B
104 22 99
207 39 55 61
132 42 66 3 23
227
198
145
164

8. Hierarchical tamper detection (2/2)
Level 4 :
104 20 99
207 39 54 61
132 42 66 3 23
227
198
145
164 1
block B
r=001110(00)=56=avg_Bs 69 78 82 97 35 46
210
102 51 33 73 44
173 83
145
126
avg_As=( )/4=57
57= = =56
avg_Bs  avg_As
block A

9. Tampered image recovery
104 20 99
207 39 54 61
132 42 66 3 23
227
198
145
164 1
block B
r=001110(00)=56 69 78 82 97 35 46
210
102 51 33 73 44
173 83
145
126 56 82 97
210
102 51 33 73 44
173 83
145
126
tamped block A
recovered block A

10. Experimental results (1/4)

11. Experimental results (2/4)

12. Experimental results (3/4)

13. Experimental results (4/4)

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