A Tunable Bound of the Embedding Level for Reversible Data Hiding with Contrast Enhancement

Abstract

Recently, histogram shifting based reversible data hiding techniques are exploited to enhance the image contrast. To avoid overflow and underflow, the cover image has to be processed before data embedment by preshifting a number of the histogram bins, at both the lower and upper ends. When the payload size becomes larger, a larger number of bins has to be pre-shifted, and thus the image contrast may get over-enhanced such that human eye perceivable image degradation appears and the image is over-sharped. To avoid image over-sharping, the just noticeable difference measurement is exploited to estimate the maximum number of pre-shiftable bins. In addition, a tunable parameter is designed to make balance between the visual effect and the embedding capacity.