Reversible Image Hiding Scheme for High Quality Based on Histogram Shifting

In 2006, Ni et al. proposed reversible image hiding scheme using histogram shifting. Their scheme modified the pixel values of the cover-image between the peak point and the zero point in the histogram. PSNR of almost every histogram shifting based methods was about 48dB because many pixels that don´t hide the secret data was modified. In this paper, to the higher hiding capacity and image quality improved Ni et al.´s scheme using Gradient-adjusted prediction (GAP) and modulo operation. In experimental results, the hiding capacity of the proposed scheme is superior to Ni et al.´s scheme. Also the image quality of the proposed scheme is increased by about 7 dB than Ni et al.´s scheme.