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