Reversible Data Embedment for Encrypted Cartoon Images Using Unbalanced Bit Flipping

Abstract

In this paper, we propose a reversible data hiding technique to improve Zhang and Hong et al.’s methods on cartoon images. Zhang and Hong et al. exploit the block complexity for data extraction and image recovery. Their methods are efficient for natural images, however, the results are unsatisfactory when applies on cartoon images consisting of large flat area. By unbalanced flipping the bits of pixel groups, the block complexity before and after flipping can be distinguished and thus the error rate can be further reduced. Experimental results show that the proposed method has lower error rate than those of Zhang and Hong et al.’s methods without degrading the image quality.