Lossless Information Hiding in Images

2.3. Difference Expansion–Based Schemes

2.3.1. Tian's Scheme

The DE technique for reversible data hiding was first proposed by Tian and Tiara [9,10]. It is a high-capacity approach based on expanding the pixel difference value between neighboring pixels. His method allows one bit to be embedded in every pair of pixels. Given a pair of 256-grayscale image pixel values (x, y), 0 ≤ x, y ≤ 255, their integer average c and difference d are computed as

c=⌊x+y2⌋,d=x−y

(2.3)

where ⌊z⌋ denotes the floor function that seeks the greatest integer less than or equal ...