Combining Interest Point and Invariant Moment for Geometrically Robust Image Watermarking
This paper presents a new robust image watermarking scheme for resisting both traditional and geometric attacks. A watermark synchronization scheme is first presented using image features. Harris interest points are first extracted from the scale normalized image and the locally most stable points are employed to generate some non-overlapped circular regions. Watermark synchronization is achieved using these local circular regions. Thereafter, the rotation invariant pseudo-Zernike moments (PZMs) are computed over each circular region and the watermark signal is composed of the PZM vectors extracted from all the local regions. Then the PZM vectors are modified and reconstructed, producing some error images. The watermark is embedded by adding the error images into the corresponding local circular regions in spatial domain directly. During watermark detection, local circular regions are first extracted from the distorted image and PZMs are computed over each local region. A minimum distance decoder is proposed to detect the watermark blindly. Simulation results on Stirmark 4.0 show that the watermark is robust against traditional signal processing attacks, rotation, scaling, flipping, Stirmark random bending as well as combined attacks.
image watermark geometric attack watermark synchronization pseudo-zernike moment stirmark feature extraction