1. Reversible Image Watermarking Using Interpolation Technique Source: IEEE Transcation on Information Forensics and Security, Vol. 5, No. 1, March 2010 Authors: Lixin Luo, Zhenyong Chen, Ming Chen, Xiao Zeng and Zhang Xiong Speaker: Hon- Hang Chang Date: 2010. 10. 27

2. Outline  Introduction  Proposed Method  Experiment Results  Conclusions 2

3. Introduction 3 Embed Cover image Watermark Watermarked image Watermark Cover image Watermarked image Extract

4. Proposed Method(Cont.) 4 LSB replacement LM, LN RM, RN Boundary Map Overhead  LSB replacement of the overhead information Marginal area of cover-image Cover image

5. ●○●○●○● ○○○○○○○ ●○●○●○● ○○○○○○○ ●○●○●○● ○○○○○○○ ●○●○●○● Proposed Method(Con.t) 5  Interpolation in Non-Sample pixels ● Sample pixel ○ Non-Sample pixel ●○●○●○● ○○○○○○○ ●○●○●○● ○○○○○○○ ●○●○●○● ○○○○○○○ ●○●○●○● ●○●○●○● ○○○○○○○ ●○●○●○● ○○○○○○○ ●○●○●○● ○○○○○○○ ●○●○●○● ●○●○●○● ○○○○○○○ ●○●○●○● ○○○○○○○ ●○●○●○● ○○○○○○○ ●○●○●○● ●○●○●○● ○○○○○○○ ●○●○●○● ○○○○○○○ ●○●○●○● ○○○○○○○ ●○●○●○● Cover image X ○ The Non-Sample pixel after predicting 1-Level 2-Level

6. ●○●○●○● ○○○○○○○ ●○●○●○● ○○○○○○○ ●○●○●○● ○○○○○○○ ●○●○●○● Proposed Method(Cont.) 6  Interpolation in Sample pixels ● Sample pixel ○ Non-Sample pixel ○ The Non-Sample pixel after predicting●○●○●○●○○○○○○○ ●○○○○○● ○○○○○○○ ●○○○○○● ○○○○○○○ ●○●○●○● 3-Level

7. Proposed Method(Cont.) 7  Interpolation in Non-Sample pixels (1/2) 60913020 2452184560 5047404350 7545672250 60 4030 S 45 = {60, 52,40} Cover image X Mean 45 =(S 45 (1)+S 45 (3))/2 =(60+40)/2 =50 Mean 135 =(S 135 (1)+S 135 (3))/2 =(30+50)/2 =40 S 135 ={30, 52,50} 60913020 2460 504050 7550 60 4030 Interpolation X ’ 4535 5045 u= ( Mean 45 + Mean 135 )/ 2 = (50+40)/2 = 45

8. Proposed Method 8  Interpolation in Non-Sample pixels (2/2) 60913020 2452184560 5047404350 7545672250 60 4030 S 0 = {30, 18,40} Cover image X S 90 ={52, 18,45} 60913020 2460 504050 7550 60 4030 Interpolation X ’ Mean 0 =(S 0 (1)+S 0 (3))/2 =(30+40)/2 =35 Mean 90 =(S 90 (1)+S 90 (3))/2 =(52+45)/2 =48.5 u= ( Mean 0 + Mean 90 )/ 2 = (35+48.5)/2 = 41.75 4535 5045 42 46 49 43 42 5.485429.0354571.0 48.5 )()( )( 35 )()( )( 900 0 0 00 '   ×        ee e ee e Meanw wX    

9. Proposed Method 9  Interpolation in Sample pixels 60913020 2452184560 5047404350 7545672250 60 4030 S 0 = {18, 40, 67} Cover image X S 90 ={47, 40, 43} 60913020 2460 50 7550 60 4030 Interpolation X ’ Mean 0 =(S 0 (1)+S 0 (3))/2 =(18+67)/2 =42.5 Mean 90 =(S 90 (1)+S 90 (3))/2 =(47+43)/2 =45 u= ( Mean 45 + Mean 135 )/ 2 = (42.5+45)/2 = 43.75 4535 5045 42 46 49 43 45

10. Proposed Method(Cont.) 10  Embedding(Non-Sample pixels) (1/2) Cover image XInterpolation X ’ RM LM RM+1 LN Difference E 60913020 1241 24474335601417 50474042501852 7550 4550 52 5060 40305473 24474335601417 60657572758164 60913020 1241 24474234591417 50474043502052 75504946495152 5060 39305273 24474434591117 60657572758164 0100 0 -2 011 012 0 113 RN LM-1 LM RM - =

11. 60913020 1241 24474234591417 50474043502052 75504946495152 5060 39305273 24474434591117 60657572758164 60913020 1241 24464333581317 50474042501852 75495145515052 5060 40305473 24464335611417 60657572758164 Proposed Method(Cont.) 11  Embedding(Non-Sample pixels) (2/2) Interpolation X ’ Difference E 60913020 1241 24474234591417 50474043502052 75504946495152 5060 39305273 24474434591117 60657572758164 0100 0 -2 011 012 0 113 RM LM RM+1LM-1 Difference E ’ 1 0 -2 2 2 012 123 W= 1 0 1 1 0 1 1 1 0 0 1 0 1 + = Interpolation X ’ Watermarked image

12. Proposed Method(Cont.)  Embedding(Sample pixels) 60913020 1241 24464333581317 50474042501852 75495145515052 5060 40305473 24464335611417 60657572758164 Watermarked image 60913020 1241 24464333581317 50474042501852 75495145515052 50606140315473 24464335611417 60657572758164 Interpolation X ’ 00 Difference E LNRN LMRM LMRM LM-1RM+1 - = 12

13. Proposed Method(Cont.)  Embedding(Sample pixels) 60913020 1241 24464333581317 50474042501852 75495145515052 50606140315473 24464335611417 60657572758164 Interpolation X ’ 00 Difference E LMRM LM-1RM+1 W= 1 0 1 1 10 -2 Difference E ’ 60913020 1241 24464333581317 50474042501852 75495145515052 50606140315473 24464335611417 60657572758164 Interpolation X ’ 60913020 1241 24464333581317 50474142501852 75495145515052 50605940295473 24464335611417 60657572758164 Watermarked image + = 13

14. Proposed Method(Cont.)  Extracting(Sample pixels) 60913020 1241 24464333581317 50474142501852 75495145515052 50605940295473 24464335611417 60657572758164 Watermarked image 60913020 1241 24464333581317 50474042501852 75495145515052 50606140315473 24464335611417 60657572758164 Interpolation X ’ 10 -2 Difference E ’ + = LM=-1 RM=0 LN=-2 RN=1 W 2 =1 0 1 1 00 Difference E 60913020 1241 24464333581317 50474042501852 75495145515052 5060 40305473 24464335611417 60657572758164 - = 14

15. Proposed Method(Cont.)  Extracting(Non-Sample pixels) 60913020 1241 24464333581317 50474042501852 75495145515052 5060 40305473 24464335611417 60657572758164 Watermarked images 60913020 1241 24474234591417 50474043502052 75504946495152 5060 39305273 24474434591117 60657572758164 Interpolation X ’ = - Difference E ’ 1 0 -2 2 2 012 123 + = 01 00 0 -2 011 012 0 113 Difference E ’ Cover Image X 60913020 1241 24474335601417 50474042501852 7550 4550 52 5060 40305473 24474335601417 60657572758164 LM=0 RM=1 LN=-3 RN=4 W 1 =1 0 1 1 0 1 1 1 0 0 1 0 1 W= W 1 ∥ W 2 15

16.  To distinguish the Boundary pixel is corresponding to genuine or pseudo Pixel in cover image: Proposed Method 16  Boundary Map (B) x=0 x ’’ =-1x ’’ =1 x=255 x ’’ =254x ’’ =256 X X Underflow Overflow Pixel in cover image: Watermarked pixel: B=…0To add ‘0’ in to the boundary map x ’’ =0x ’’ =255 x=1 x ’’ =0x ’’ =2 x=254 x ’’ =253x ’’ =255 B=…1To add ‘1’ in to the boundary map  Overflow and Underflow

17. Experiment Results 17 TABLE I COMPARISON RESULTS IN TERMS OF THE CAPACITY (bits) AND THE PSNR VALUE (dB) FOR LENA, BABOON, PLANE, AND SAILBOAT

18. Experiment Results 18 Fig. 1 Performance evaluation of multilayer embedding over standard in test image Lena

19. Conclusions 19  The computation cost of the proposed method scheme is small.  The proposed scheme could guarantee high image quality without sacrificing embedding capacity.