Efficient halftone image steganography based on dispersion degree optimization

Halftone images are usually used in facsimile and halftone image steganography can be used for facsimile channel. In recent years, real-time image processing becomes more and more important. In this paper, an efficient block-based steganographic method for halftone images is proposed. This method is based on optimal dispersion degree (DD), which can measure the complexity of the region texture. To reduce the visual distortion, the blocks with complex texture can be selected as carriers according to the dispersion degree. Finally, the secret messages are embedded by flipping the pixels that can minimize the changes of texture structure. The experiments demonstrate that the proposed scheme maintains a good image visual quality and realizes acceptable statistical security with high capacity.