Reversible Watermarking Based on Hierarchical Rectangle Block Division

This paper is to provide a low complexity reversible watermarking algorithm that can keep a high image quality after embedding message. This algorithm improves the traditional histogram shifting method to get more embedding capacity. The idea behind the proposed algorithm is to recursively divide original image into several non-overlapped blocks of pixels and hides secret message separately into individual blocks using traditional histogram shifting method. Using the recursive division scheme, the algorithm can easily find a suitable non-overlapped partition of the image to significantly increase embedding capacity. Experimental results reveal that the proposed method can indeed provide larger embedding capacity than the traditional histogram shifting method while maintaining a high visual quality that is comparable to the traditional one without recursive block division.