Adjacent quad modification algorithm for reversible data hiding

1. Adjacent quad modification algorithm for reversible data hiding Source ：Intelligent Information Hiding and Multimedia Signal Processing (IIH-MSP), 2010 Sixth International Conference Authors : Hsiang-Cheh Huang, Ting-Wei Chen, Feng-Cheng Chang Speaker：Jiun-Lwen Liang Date ： 2012/12/19

2. Outline • Introduction • Related work • Proposed scheme • Embedded • Extraction • Experimental results • Conclusions

3. Introduction • Today, the Internet is a popular channel that allows users to exchangeinformation without geographic limitations. • Protectingtransmitted media is becoming an increasingly important issue. • Reversible data hiding can be classified into two types: • Histogram shifting • Difference value . .

4. Related work 1/4 • Step2: To shift the pixels of histogram • If P>Z → To shift the range of the histogram , [Z+1, P-1], to the left-hand side by 1 unit. • If P<Z → To shift the range of the histogram , [P+1, Z-1], to the right-hand side by 1 unit. ------------------------------------------------------ • Step3: To hide the secret data by pixels P • If P>Z → To be embedded bit is “1”, the pixel value is changedto P-1. If the bit is ”0”, the pixel value remains. • If P<Z → To be embedded bit is “1”, the pixel value is changedto P+1. If the bit is ”0”, the pixel value remains.

5. Related work 2/4 Original image Peak point Zero point P=3, Z=6and P<Z shift to right-hand [3+1,6-1] 4 → 5 5 → 6

6. Related work 3/4 Secret bits: 1 1 0 0 1 1 0 1 Using P=3, 0 → 3 1→ 4 Marked image

7. Related work 4/4 P=3, Z=6 Extracted secret bits: 1 1 0 0 1 1 0 1 Extract 3 → 0 4→ 1 Marked image 6→ 5 5 → 4 4→ 33→ 3 Recover Original image

8. A 162 B 163 C 162 D 161 2 X 2 Original image difference : 2 X 2 • Proposed scheme

9. 162 162 TH = 1 1 1 0 0 -1 -1 d’ d TH 8 -TH 7 6 5 4 3 2 1 2 X 2 2 X 2 0 -4 -3 -2 -1 0 1 2 3 Difference histogram • Proposed scheme

10. 162 162 TH = 1 2 1 S = 1 S = 1 0 0 0 -1 -1 d’ S = 0 Embed 0 8 Embed 1 7 Embed 1 6 5 4 3 d’’ 2 1 2 X 2 2 X 2 0 -4 -3 -2 -1 0 1 2 3 Difference histogram • Proposed scheme-Embedded 1/2

11. 162 162 164 2 Stego pixels： 162 0 161 -1 d’’ 2 X 2 2 X 2 • Proposed scheme-Embedded 2/2 Stego image

12. 162 162 164 2 162 0 161 -1 difference : Stego image difference 2 X 2 2 X 2 • Proposed scheme-Extraction 1/3

13. 162 162 TH = 1 1 2 d’b = 1 S : 1 0 0 -1 -1 d’d = -1 S : 0 Extract S=0 8 7 Extract S=1 6 5 4 3 d‘ d’’ 2 1 2 X 2 2 X 2 0 -4 -3 -2 -1 0 1 2 3 Difference histogram • Proposed scheme-Extraction 2/3

14. 162 162 TH = 1 1 163 0 162 161 -1 TH 8 -TH 7 6 5 4 3 d’ cover pixels 2 1 2 X 2 2 X 2 0 -4 -3 -2 -1 0 1 2 3 Difference histogram • Proposed scheme-Extraction 3/3

15. Original image • Experimental results 1/4 TH=1 , PSNR =50.29db Capacity=34423bits

16. Experimental results 2/4 TH The image quality and the capacity with the Lena image.

17. Experimental results 3/4

18. Experimental results 4/4 The image quality and the capacity under several modification levels with the Lena image.

19. Conclusions • Higher capacity and better image quality. • The combinations of threshold values provided the increased flexibility for data protection.