Adaptive image steganographic scheme based on Tri-way Pixel-Value Differencing

To increase the capacity of the hidden secret information and to provide a stego-image imperceptible for human vision, a novel steganographic approach based on tri-way pixel-value differencing (TPVD) is presented in this paper. This approach uses three different directional edges effectively to design the tri-way differencing scheme and to remove the capacity limitation of the original PVD method using only one direction. In addition, we propose an optimal selection approach for the reference point and adaptive rules to reduce distortion brought from setting larger embedding capacity. The theoretical estimation and experimental results demonstrate that our scheme can provide a superior embedding capacity. Besides, the embedded confidential information can be extracted from stego-images without the assistance of original images.