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Reversible data hiding for high quality images using interpolation and reference pixel distribution mechanism. Source : Journal of Visual Communication & Image Representation Authors : Wien Hong, Tung-Shou Chen Presenter : Nguyen Thai Son Date : December, 20th 2010. OUTLINE. INTRODUCTION
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Reversible data hiding for high quality images using interpolation and reference pixel distribution mechanism • Source: Journal of Visual Communication & Image Representation • Authors: Wien Hong, Tung-Shou Chen • Presenter: Nguyen Thai Son • Date: December, 20th 2010
OUTLINE • INTRODUCTION • PROPOSED SCHEME • EXPERIMENTAL RESULTS • CONCLUSIONS 2
INTRODUCTION Bilinear Interpolation 3
INTRODUCTION Bilinear Interpolation f(x,y)=(4+3+3+2)/4 3 4
PROPOSED SCHEME (1/10) Reference pixel distribution mechanism (RPDM) Step 1: Create binary image B Step 2: For pixel Iij satisfy Bi,j = 0, Mod(i/+j/,2)=0 and Set Bi,j = 1 Step 3: For pixel Iij satisfy Bi,j = 0, Bi+,j=0, Bi,j+=0 and Bi+,j+=0 Range(Ii,j, Ii+,j, Ii,j+, Ii+,j+) > T1 Set Bi’,j’ = 0 where i<i’<i +, j<j’<j + T0 < T1: thresholds Range () is absolute difference of min and max value
PROPOSED SCHEME (2/10) Reference pixel distribution mechanism (RPDM) T0=5, T1 =50 =3
PROPOSED SCHEME (3/10) Reference pixel distribution mechanism (RPDM) Step 2: For pixel Iij satisfy Bi,j = 0, Mod(i/+j/,2)=0 and Rang (34,35,36,37) = |34-37| = 3 < T0 = 5 1
PROPOSED SCHEME (4/10) Reference pixel distribution mechanism (RPDM) Step 3: For pixel Iij satisfy Bi,j = 0, Bi+,j=0, Bi,j+=0, Bi+,j+=0 Range(40,70,22,177) = |22-177| = 155 > T1 =50 1
PROPOSED SCHEME (6/10) Embedding phase 10
PROPOSED SCHEME (7/10) 7 6 5 4 3 2 1 0 -7 -6 -5 -4 -3 -2 -1 0 1 2 Embedding phase Predicted image P Binary Image B Image I’ E = I’ - P
PROPOSED SCHEME (8/10) Embedding phase P1 7 P2 6 5 4 3 2 1 0 -7 -6 -5 -4 -3 -2 -1 0 1 2 E Z2 Z1
PROPOSED SCHEME (9/10) Embedding phase S= 10110010001 E’ Embedding rule: e = P1 and secret bit =0 , keep unchanged e = P1 and secret bit =1 , e’ = e +1 e = P2 and secret bit =0 , keep unchanged e = P2 and secret bit =1 , e’ = e -1
PROPOSED SCHEME (10/10) Embedding phase 31 34 35 33 37 E’ Predicted image P Stego image Is = E’ + P
Conclusions Better visual quality of stego image High embedding capacity