General Pairwise Modification Framework for Reversible Data Hiding in JPEG Images

Pairwise modification is one of the most effective ways to solve the critical issues of balancing the embedding capacity, image distortion, and file expansion in JPEG reversible data hiding (RDH). To design a satisfactory scheme based on pairwise modification, existing schemes focus on improving pairing rules, two-dimensional (2D) mappings, or ordering strategies separately while neglecting the connections between them. As a result, once pairing rules are changed, the correlative 2D mapping and ordering strategies are no longer available. To address such issues, this study proposes a framework that automatically generates optimal 2D mappings and efficient ordering strategies only by carefully initializing pairing rules. To construct optimal 2D mappings, a 2D mapping mathematical model is built to form a feasible 2D mapping solution space, in which optimal solutions are found, to assign efficient mappings for pairs with high probability. To design efficient ordering strategies, all frequencies are ranked according to an embedding evaluation model to determine more suitable ACs for data embedding. To initialize better pairing rules, this study selects nonzero ACs within +/- 2 for interblock pairing to form a more centralized pairwise histogram. The experimental results show that the proposed scheme introduces minor file expansion and obtains better visual quality than existing JPEG RDH schemes when the payload is the same as.