A reversible data hiding algorithm based on bidirectional

A reversible data hiding algorithm based on bidirectional difference expansion Source: Multimedia Tools and Applications (2019) Author: Weiqing Wang Speaker: Chi Hengxiao Date: 2020/01/13 1

Outline • Introduction • Proposed scheme • Experiments • Conclusions 2

Introduction 3

Proposed scheme(1/3)---Data embedding 162 163 156 Z 162 163 157 162 160 163 156 162 163 157 161 162 157 162 163 v is the average value d is the difference A(k) A(k+1) v =162 d=1<T T= 10 Secret data=11011001 A’(k)=162 -1 -1=160 A’(k+1)=162+1=163 4

Proposed scheme(2/3)---Data embedding 162 163 156 Z 162 163 157 160 168 153 162 167 163 159 157 160 161 165 162 154 157 163 151 156 161 162 157 163 156 v is the average value d is the difference A(k) A(k+1) v =160 d=7<T T= 10 Secret data=11011001 A’(k)=160+7+1=168 A’(k+1)=160 -7=153 5

Proposed scheme(3/3)---Data extraction d’为偶数则之前嵌入 0，d=d’/2; d’为奇数则之前嵌入 1，d=(d’-1)/2 160 163 165 157 154 162 168 156 151 162 156 163 167 159 161 160 162 T=10 当d’>2 T-1时 165 154 160 162 v=160 d’=11<2 T-1 b=1 d=5 A(k)=162 A(k+1)=157 v=161 d’=2<2 T-1 b=0 d=1 A(k)=161 A(k+1)=162 6

Experiments – (1/5) 7

Experiments – (2/5) 8

Experiments – (3/5) 9

Experiments – (4/5) 10

Experiments – (5/5) 11

Conclusions 1. A RDH algorithm based on bidirectional difference extension was proposed 2. PSNR ↑ 3. EC ↑ 4. Security ↑ 17