A content-adaptive approach for reducing embedding impact in steganography

In this paper, a content-adaptive steganographic scheme is proposed. The novel scheme can be viewed as an improvement of the conventional LSB matching. In this scheme, we take advantage of embedding redundancy in LSB matching to select modification direction (i.e., increasing or decreasing the pixel value by 1), and the dependency of neighboring pixels is taken into consideration. More specifically, if the secret message bit does not match the LSB of the corresponding cover pixel value, the choice of modification direction is not random but a specific selection, in order to hold the correlation of neighboring pixels as far as possible. The resulting stego image looks more like a natural one, and smooth to some extent. Comparing with LSB matching and other state-of-the-art steganography, higher level security of the proposed scheme is experimentally verified. In addition, the proposed approach can be also applied in LSB-based steganography to enhance the security.