A New Reversible Data Hiding Scheme with Pixel-to-Block Mapping
Hussain Nyeem, Md Fazla Elahi, Md Abdul Wahed · 2018
This paper presents a new reversible data hiding (RDH) scheme with pixel-to-block (PTB) mapping. Due to the sub-optimal changes in the up-sampled pixels, requirement of additional knowledge of look-up table and location map, or direct and unconditional embedding into the least significant bits, existing PTB-based schemes are inefficient. We propose to compute a 2 × 2 block from an original pixel by copying it to all the four pixels. A unique block mapped to the value of 4-bit data is then constructed by keeping the first pixel of the block intact and modifying the others with minimum possible changes. Thereby a better embedding rate-distortion performance is obtained and the overflow and underflow problem is effectively tackled without requiring any location map or lookup table. The presented rate-distortion analysis of our scheme demonstrated a significant improvement compared to the state-of-the-art RDH schemes with PTB.