Reversible Data Hiding Scheme Based on Adjusting Pixel Modulation and Block-Wise Compression for Encrypted Images

Reversible data hiding in encrypted image (RDHEI) is a technique that can provide the security and invisibility of their own information during the acquisition and sharing of them among multi-users. Among which, parametric binary tree labelling (PBTL) is a novel technique designed to serve for high-capacity RDHEI. However, considering the local smoothness of the image, its potential redundancy room has not been fully explored. In this paper, we propose an improved PBTL-RDHEI scheme (IPBTL-RDHEI in short). In IPBTL-RDHEI, an adjusting pixel modulation strategy is considered to reduce the probability of the overflow of pixels, making more embeddable pixels usage to carry secret data. Moreover, a blockwise rearrangement and compression (BRC) mechanism is introduced to decrease the length of the required auxiliary information. Experimental results confirm that the proposed scheme is able to achieve an average embedding rate as large as 1.827 bpp when the block size is set to 3×3.