Reversible Watermarking Based on the Invariant Sum Value

A novel reversible data hiding scheme based on the invariant sum values of pixel pairs is presented in this paper. For each pixel pair, if a certain value is added to one pixel while the same value is subtracted from the other pixel, then the sum of these two pixels will remain unchanged. This value is selected as the half of difference plus 1-bit watermark considering the distortion control and the reversibility of the algorithm. The watermark bit can be extracted by using the invariability of the sum values and the equality property between the parities of the sum values and the difference values. The experimental results reveal that the proposed method has comparable performance with the traditional difference expansion method in visual quality and embedding capacity.