1. 1 Data Hiding Watermarking for Halftone Images Ming Sun Fu, Student Member, IEEE, and Oscar C. Au, Senior Member, IEEE, IEEE TRANSACTIONS ON IMAGE PROCESSING, Vol. 11, No. 4, Apr. 2002, pp. 477 -484

2. 2 Outline Introduction Data Hiding without Original Multitone Image (DHST, DHPT, DHSPT) Data Hiding with Original Multitone Image (DHED, MDHED) Conclusions

3. 3 Introduction Halftone images Error diffusion Jarvis kernel and Steinberg kernel

4. 4 Data Hiding without Original Multitone Image (DHST, DHPT, DHSPT) Data Hiding Self Toggling(DHST) use seed generate a set of N pseudo-random location. embedded 0 or 1 ( 1 bit ) simple & error correction coding “ salt-and-pepper ” noise intensity being about 128 location [ 10, 752, 950,... ] hiding bit stream [ 0 1 0... halftone image Ex. 150 * 150

5. 5 Data Hiding without Original Multitone Image (DHST, DHPT, DHSPT) Data Hiding Pair Toggling(DHPT) slave pixel is chosen randomly. two errors are introduced instead of one complexity is slightly larger than DHST fewer “ salt-and-pepper ” noise M=

6. 6 Data Hiding without Original Multitone Image (DHST, DHPT, DHSPT) Data Hiding by Smart Pair Toggling(DHSPT) Candidate is Min [con after (m,n)] Define 2 2x0x0 2 2 11 x0x0 11

7. 7 Data Hiding without Original Multitone Image (DHST, DHPT, DHSPT) Data Hiding by Smart Pair Toggling(DHSPT) Ex. before after 1+2+2=5 2+1+2+1+1=7 1 00 0 X 0 =1 1 0 10 + 1 00 0 X 0 =0 1 0 10 - = 12

8. 8 Data Hiding without Original Multitone Image (DHST, DHPT, DHSPT) W( f(X 0, X master ) + f(X 0, X master ) ) = 2 before after vertical or horizontal master w(i) = 2  con before (m, n) + con after (m, n) = 10 other master w(i) = 1  con before (m, n) + con after (m, n) = 11 X master =1X 0 =0 X master =1X 0 =1 - -

9. 9 Data Hiding without Original Multitone Image (DHST, DHPT, DHSPT) con before =1+2+2+1+2=8  con after =11-8=3 1010 1110 1000 1001 con before =2+2+1=5  con after =10-5=5 con before =0  con after =10-0=10 1010 1010 1010 1001

10. 10 Data Hiding with Original Multitone Image (DHED, MDHED) Error diffusion

11. 11 Data Hiding with Original Multitone Image (DHED, MDHED) Error diffusion

12. 12 Data Hiding with Original Multitone Image (DHED, MDHED) Error diffusion

13. 13 Data Hiding with Original Multitone Image (DHED, MDHED) Data Hiding Error Diffusion

14. 14 Data Hiding with Original Multitone Image (DHED, MDHED) Modified Data Hiding Error Diffusion

15. 15 Conclusions 4096/(512*512)=1.6 % 28900/(512*512)=11 %

16. 16 Conclusions 隱藏少量資料時 不見得取得優勢 隱藏多量資料時 good choice 28900/4096 = 7 倍 Steinberg 皆優於 Jarvis kernel