Reversible data hiding for halftone images using histogram modification

This paper presents a reversible data hiding method for halftone images, which is an improved version of a histogram modification technique for data hiding with grayscale images. Each block (i.e., n-bits binary) of a halftone bitmap is transformed into a decimal format in order to use a histogram modification method. Furthermore, this is the first attempt to embed data into a halftone image using histogram modification. Our proposed method has low complexity and achieves a high embedding capacity with good perceptual quality compared to the prior arts. In an experiment, our data hiding method has verified by a comparison with previous methods.