A high capacity reversible data hiding scheme using orthogonal projection and prediction error modification

The payload of a histogram-shifting based reversible data hiding technique is primarily determined by the peak height of the corresponding image histogram. It is known that the peak height of the prediction error histogram is usually higher than that of image histogram itself. In 2009, Tsai et al. adopted the idea of histogram-shifting technique and embedded message by modifying the prediction errors to achieve a higher payload. They used a block-based approach and leaved some pixel values unmodified to predict other pixel values in a block. However, the unmodified pixels took up some embeddable space, causing a reduction in payload. In this paper, a new reversible data hiding technique based on prediction error modification is proposed. The orthogonal projection technique is employed to estimate the optimal weights of a linear predictor to increase the prediction accuracy and the embedding capacity. The experimental results revealed that the proposed method outperformed the existing histogram-shifting based reversible data hiding technique in terms of payload and image quality.