In this study, an optima pixel adjustment process applies separately to adaptive and reversible data hiding algorithms. In the first part of this study, we propose a block-based adaptive data hiding algorithm considering both the optimal pixel adjustment process and the pixel-value differencing scheme. The cover image is first partitioned into non-overlapping blocks with m-by-n pixels. A dynamic block subdivision is employed on the boundary region to address the problem of inaccurate complexity estimation in previous algorithm. We also modify the embedding equation to solve the overflow problem. The experimental results show that our proposed algorithm can achieve an adjustable embedding capacity according to the block size. The proposed technique is feasible in adaptive data hiding.
In the second part of this study, we propose a generalized image interpolation-based reversible data hiding scheme with high embedding capacity and image quality. This study modifies the pixel mapping scheme and adopts a bilinear interpolation to solve boundary artifacts. Thus, our scheme can support magnified images at any resolution. Thereafter, the modified reference pixel determination and an optimal pixel adjustment process can effectively enhance the embedding capacity and the image quality. The experimental results show our proposed algorithm achieves a higher embedding capacity under acceptable visual distortions, and can be applied to a magnified image at any resolution. Our proposed technique is feasible in reversible data hiding.
