A Computation Model for Capacity and Robustness of Robust Image Watermarking Scheme in Spatial Domai

In order to more accurately evaluate a robust image watermarking scheme, formulas of calculating capacity and robustness of the scheme are proposed in this paper. Firstly, non-blind robust image watermarking scheme is discussed. Based on the scheme model built in spatial domain, the formulas of calculating capacity and robustnessare drawn in detail. Then the models and capacity and robustness formulas of blind watermarking scheme and public-key scheme are also drawn. According to the formula, it is obtained that capacity is in contradiction with robustness.