Reversible Image Watermarking Using Interpolation Technique

1. Reversible Image Watermarking Using Interpolation Technique Source: IEEE Transcation on Information Forensics and Security, Vol. 5, No. 1, March 2010 Authors: LixinLuo, 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

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

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

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

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

7. Proposed Method(Cont.) • Interpolation in Non-Sample pixels(1/2) Mean45=(S45(1)+S45(3))/2 =(60+40)/2 =50 Mean135=(S135(1)+S135(3))/2 =(30+50)/2 =40 u= ( Mean45+ Mean135 )/ 2 = (50+40)/2 = 45 Cover image X S45= {60, 52,40} S135={30, 52,50} 45 35 50 45 Interpolation X ’

8. Proposed Method = · + · ' X w Mean w Mean 0 0 90 90 s s ( e ) ( e ) = · + · 90 0 35 48.5 s + s s + s ( e ) ( e ) ( e ) ( e ) 0 90 0 90 = • × + • × 0 . 4571 35 0 . 5429 48 . 5 » 42 • Interpolation in Non-Sample pixels(2/2) Mean0=(S0(1)+S0(3))/2 =(30+40)/2 =35 Mean90=(S90(1)+S90(3))/2 =(52+45)/2 =48.5 u= ( Mean0+ Mean90 )/ 2 = (35+48.5)/2 = 41.75 Cover image X S0= {30, 18,40} S90={52, 18,45} 45 42 35 46 43 49 50 45 Interpolation X ’

9. Proposed Method • Interpolation in Sample pixels Mean0=(S0(1)+S0(3))/2 =(18+67)/2 =42.5 Mean90=(S90(1)+S90(3))/2 =(47+43)/2 =45 u= ( Mean45+ Mean135 )/ 2 = (42.5+45)/2 = 43.75 Cover image X S0= {18, 40, 67} S90={47, 40, 43} 45 42 35 45 46 43 49 50 45 Interpolation X ’

10. Proposed Method(Cont.) • Embedding(Non-Sample pixels) (1/2) - = Cover image X Interpolation X ’ Difference E LM RM LM RM LN RN LM-1 RM+1

11. Proposed Method(Cont.) W= 1 0 1 1 0 1 1 1 0 0 1 0 1 • Embedding(Non-Sample pixels) (2/2) Difference E’ + Interpolation X ’ Difference E LM RM Interpolation X ’ = LM-1 RM+1 Watermarked image

12. Proposed Method(Cont.) • Embedding(Sample pixels) - = Watermarked image Interpolation X ’ Difference E LM RM LM RM LN RN LM-1 RM+1

13. Proposed Method(Cont.) W= 1 0 1 1 • Embedding(Sample pixels) Difference E’ + Interpolation X ’ Difference E Interpolation X ’ LM RM = LM-1 RM+1 Watermarked image

14. Proposed Method(Cont.) • Extracting(Sample pixels) = - Watermarked image Interpolation X ’ Difference E’ + LM=-1 RM=0 LN=-2 RN=1 = Difference E W2=1 0 1 1

15. Proposed Method(Cont.) • Extracting(Non-Sample pixels) = - Watermarked images Interpolation X ’ Difference E’ + LM=0 RM=1 LN=-3 RN=4 = Difference E’ W1=1 0 1 1 0 1 1 1 0 0 1 0 1 W= W1 ∥W2 Cover Image X

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

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

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

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