Dual-image Reversible Data Hiding Based on Sudoku Block Mapping and Adaptive Embedding

Dual-image reversible data hiding (RDH) schemes typically hide secret data in the cover image to generate two marked images that must be received by two trusted receivers over public transmission channels. To measure the performance of an RDH method, the two important indicators are embedding capacity and visual quality. However, existing dual-image RDH studies usually cannot keep a better trade-off between them. To address this issue and improve data security, we propose an efficient dual-image RDH scheme based on Sudoku block mapping in this paper. It is worth noting that our scheme can nicely balance the two indicators, presenting a high embedding ratio at 1.5 bits per pixel at most and better visual quality in lower payload circumstances compared with state-of-the-art dual-image RDH schemes. The average peak signal-to-noise ratio of the proposed scheme on tested images is as high as 68.70 dB for the given payload of 20,000 bits.