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

Abstract

Recently, histogram modification based reversible data hiding (RDH) techniques are exploited to enhance the image contrast. To avoid overflow and underflow, the cover image has to be pre-processed by pre-shifting a number of the histogram bins at the lower and upper ends. When the payload size becomes large, a larger number of histogram bins has to be pre-shifted, and thus the image contrast may be over enhanced. As a result, human eye perceivable image degradation may appear in the over-sharpened image. To avoid image over-sharping, the just noticeable difference measurement is exploited to estimate the maximum number of pre-shiftable histogram bins. In addition, a tunable parameter is designed to balance between the visual degradation and the embedding capacity. The experimental result shows that the proposed work is effective in estimating the bound of embedding level.