Reversible image watermarking by rhombus prediction and histogram modification

A histogram based reversible data hiding algorithm is proposed for digital images with the rhombus prediction scheme. With the prediction errors generated in each of the two phases, data embedding is performed by modifying their histogram while the overflow and underflow of pixel values are prevented in pre-process. Blind data extraction and exact recovery of the original image are both enabled by saving the overhead information into the watermarked image. Furthermore, high-capacity embedding can be performed by using multiple pairs of histogram bins to host the embedded data. The numerical results show that good performance can be achieved with the proposed algorithm, especially when the embedding rate is high.