Reversible Watermarking using Image Content Assessment and Histogram Shifting

Reversible data hiding is a technique to embed additional message into some distortion-unacceptable cover media, such as military or medical images, in a reversible manner so that the original cover content can be perfectly restored after extraction of the hidden message. This paper presents a new method using histogram shifting that aims at reducing the embedding distortion and improving watermark payload. The embedding capacity of a histogram-based reversible data hiding technique is primarily determined by the peak height of the histogram. Recently, some studies have tried to embed data in the histogram of prediction errors by modifying the error values. Previous methods insert data only in smooth areas. But by applying the histogram modulation to the image prediction-errors and by considering their immediate pixel neighborhood, the method we propose inserts data in textured areas also. The proposed method, which can be applied to both natural and medical images, outperforms prior works in terms of payload and PSNR.