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Mathematical Problems in Engineering
Volume 2017, Article ID 6581279, 14 pages
https://doi.org/10.1155/2017/6581279
Research Article

Texture Directionality-Based Digital Watermarking in Nonsubsample Shearlet Domain

1School of Information Science and Technology, Northwest University, Xi’an 710127, China
2School of Mathematics, Northwest University, Xi’an 710127, China

Correspondence should be addressed to Jian Jia; nc.ude.uwn@naijaij

Received 23 February 2017; Revised 23 April 2017; Accepted 10 May 2017; Published 12 June 2017

Academic Editor: Alessandro Lo Schiavo

Copyright © 2017 Jian Zhao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Digital watermarking is a technique used to protect an author’s copyright and has become widespread due to the rapid development of multimedia technologies. In this paper, a novel watermarking algorithm using the nonsubsample shearlet transform is proposed, which combines the directional edge features of an image. A shearlet provides an optimal multiresolution and multidirectional representation of an image based on distributed discontinuities such as edges, which ensures that the embedded watermark does not blur the image. In the proposed algorithm, the nonsubsample shearlet transform is used to decompose the cover image into directional subbands, where different directional subbands represent different directional and textured features. The subband whose texture directionality is strongest is selected to carry the watermark and is thus suitable for the human visual system. Next, singular value decomposition is performed on the selected subband image. Finally, the watermark is embedded in the singular value matrix, which is beneficial for the watermarking robustness and invisibility. In comparison with related watermarking algorithms based on discrete wavelet transforms and nonsubsample contourlet transform domains, experimental results demonstrate that the proposed scheme is highly robust against scaling, cropping, and compression.