Pixel-Value-Ordering Based Reversible Data Hiding with Adaptive Texture Classification and Modification

Pixel-value-ordering (PVO) is a new technique for the high-fidelity reversible data hiding (RDH). It contains a process of sorting the pixels of a block by their values at first and then embedding into data bits into the maximum or minimum pixels of a block. In this paper, we propose to modify the pixel blocks differently according to how smooth they are, and embed the adequate number of bits into different types of blocks. The pixel blocks are first classified into five types based on the local complexity. The maximum pixels of the most smooth block will be embedded at most four bits, and the less smooth ones are embedded with a lower number of bits. The block classification is dynamically adjusted to achieve the adaptive embedding with the best trade-off between the capacity and the embedding distortion. Experimental results show that the proposed method can give a better performance over the previous PVO-based methods.