Digital watermarking is a technique used to protect an author�s copyright and has become widespread due to the rapid development\nofmultimedia technologies. In this paper, a novel watermarking algorithm using the nonsubsample shearlet transformis proposed,\nwhich combines the directional edge features of an image. A shearlet provides an optimal multiresolution and multidirectional\nrepresentation of an image based on distributed discontinuities such as edges, which ensures that the embedded watermark does\nnot blur the image. In the proposed algorithm, the nonsubsample shearlet transform is used to decompose the cover image into\ndirectional subbands,where different directional subbands represent different directional and textured features.Thesubbandwhose\ntexture directionality is strongest is selected to carry the watermark and is thus suitable for the human visual system. Next, singular\nvalue decomposition is performed on the selected subband image. Finally, the watermark is embedded in the singular value matrix,\nwhich is beneficial for the watermarking robustness and invisibility. In comparison with related watermarking algorithms based on\ndiscrete wavelet transforms and nonsubsample contourlet transformdomains, experimental results demonstrate that the proposed\nscheme is highly robust against scaling, cropping, and compression.
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