Practical Performance Analysis of Secure Modulations for WOA Spread-Spectrum based Image Watermarking

This paper presents the first practical analysis of secure modulations for watermarking of still images in the case of a WOA (Watermarked Only Attack) attack framework (the attacker observes only marked contents). Two recent spread spectrum modulations, namely Natural Watermarking (NW) and Circular Watermarking (CW) are compared against classical modulations, namely Spread Spectrum (SS) and Improved Spread Spectrum (ISS). Results are discussed from the distorsion point of view, as well as from the the robustness rind security point of view. We emphasize that the experiments were carried out on a rather significant number of images (2000) and demonstrate the relevance of these modulations in a real-world application.