Improved Pairwise Embedding for High-Fidelity Reversible Data Hiding

Pairwise reversible data hiding (RDH) restricts the embedding to 3 combinations of bits per pixel pair (“00”, “01”, “10”), by eliminating the embedding of “1” into both pixels. The gain in quality is significant and the loss in embedding bitrate is compensated by embedding into previously shifted pairs. This restriction requires a special coding procedure to format the encrypted hidden data. This paper proposes a new set of embedding equations for pairwise RDH. The proposed approach inserts either one or two data bits into each pair based on its type, bypassing the need for special coding. The proposed equations can be easily integrated in most pairwise reversible data hiding frameworks. They also provide more room for data embedding than their classic counterparts at the low embedding distortion required for high-fidelity RDH.