Blind Watermarking Algorithm Against Geometric Attacks Based on Directionlet-domain
一种可抵抗几何攻击的Directionlet变换域盲水印算法

Watermark robustness to geometric attacks is still a challenging issue. A blind watermarking scheme is proposed against geometric attacks to construct watermark synchronization information by using Directionlet: Firstly, the edge detection operator is utilized to extract image edges; Then, the slope of those edges are computed according to Lagrange theorem; Finally, the direction vector of the two choosed edges constitute the generator matrix of Directionlet; Watermark are adaptively embedded into Directionlet coefficients of the selected cosets. It is Directionlet matrix formed of image edges that eliminates the effect of geometric attacks. Experimental results show the proposed watermarking algorithm is robust, especially at the geometric attacks such as rotation.