Two-dimensional histogram-based reversible contrast enhancement using bi-histogram equalization

Abstract

In recent years, the reversible data hiding with contrast enhancement (RDH-CE) technique has been proposed and developed significantly; it can perform CE for images and restore the host image losslessly. To improve the embedding rate, CE capability, and visual quality, this paper proposes a reversible CE scheme based on 2D histogram equalization, which maintains the image quality and low brightness distortion with fewer iterations and has a high embedding rate and CE capability. Specifically, to prevent image brightness distortion, the 2D histogram is separated to obtain two 2D sub-histograms before histogram shifting. The dimension with the highest embedding capacity is dynamically selected for the embedding operation in each iteration, and the two-sided histogram equalization and information embedding are performed on the separated sub-histograms. The proposed method is evaluated on two datasets, and the results show that the method has high embedding and CE capabilities with low iteration and good visualization.