Reversible Data Hiding under Inconsistent Distortion Metrics.

Recursive code construction (RCC), based on the optimal transition probability matrix (OTPM), approaching the rate-distortion bound of reversible data hiding (RDH) has been proposed. Using the existing methods, OTPM can be effectively estimated only for a consistent distortion metric, i.e., if the host elements at different positions share the same distortion metric. However, in many applications, the distortion metrics are position dependent and should thus be inconsistent. Inconsistent distortion metrics can usually be quantified as a multi-distortion metric. In this paper, we first formulate the rate-distortion problem of RDH under a multi-distortion metric and subsequently propose a general framework to estimate the corresponding OTPM, with which RCC is extended to approach the rate-distortion bound of RDH under the multi-distortion metric. We apply the proposed framework to two examples of inconsistent distortion metrics: RDH in color image and reversible steganography. The experimental results show that the proposed method can efficiently improve upon the existing techniques.