Reversible Watermarking Schemes Using Spatial Quad-Based Difference Expansion

In this paper, we make use the fact that the differences between the pixel values in the local region of an image are small and propose two simple and effective reversible watermarking schemes based on the spatial quad-based difference expansion that applies the difference expansion to the image in row-wise and column-wise simultaneously. The schemes make good use of both row-wise and column-wise pixel pairs with small differences. Experimental results show our schemes are effective.