  In this paper, a new reversible data hiding (RDH) algorithm that is based on
the concept of shifting of prediction error histograms is proposed. The
algorithm extends the efficient modification of prediction errors (MPE)
algorithm by incorporating two predictors and using one prediction error value
for data embedding. The motivation behind using two predictors is driven by the
fact that predictors have different prediction accuracy which is directly
related to the embedding capacity and quality of the stego image. The key
feature of the proposed algorithm lies in using two predictors without the need
to communicate additional overhead with the stego image. Basically, the
identification of the predictor that is used during embedding is done through a
set of rules. The proposed algorithm is further extended to use two and three
bins in the prediction errors histogram in order to increase the embedding
capacity. Performance evaluation of the proposed algorithm and its extensions
showed the advantage of using two predictors in boosting the embedding capacity
while providing competitive quality for the stego image.
