Geometric invariant watermarking by local Zernike moments of binary image patches

A novel digital image watermarking scheme based on feature extraction and local Zernike transform is proposed in this paper. We proposed a local Zernike moments based watermarking scheme where the watermarked image/region can be obtained directly by inverse Zernike Transform. An edge-based feature detector is proposed for local region extraction, with which, the distinct circular patch of given size can be extracted for watermark embedding and extraction. The extracted circular patch is decomposed into a collection of binary patches and Zernike transform is applied to the selected binary patches. Magnitudes of the local Zernike moments are calculated and modified to embed the watermarks. Experimental results show that the proposed watermarking scheme is very robust against geometric distortion such as rotation, scaling, cropping, and affine transformation; and common signal processing such as JPEG compression, median filtering, and low-pass Gaussian filtering.