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Robust dual color images watermarking scheme with hyperchaotic encryption based on quaternion DFrAT and genetic algorithm

Luo Hui-Xin, Gong Li-Hua, Chen Su-Hua

Optica Applicata

2023

Vol. 53, nr 2

261--280

A robust dual color images watermarking algorithm is designed based on quaternion discrete fractional angular transform (QDFrAT) and genetic algorithm. To guarantee the watermark security, the original color watermark image is encrypted with a 4D hyperchaotic system. A pure quaternion matrix is acquired by performing the discrete wavelet transform (DWT), the block division and the discrete cosine transform on the original color cover image. The quaternion matrix is operated by the QDFrAT to improve the robustness and the security of the watermarking scheme with the optimal transform angle and the fractional order. Then the singular value matrix is obtained by the quaternion singular value decomposition (QSVD) to further enhance the scheme’s stability. The encryption watermark is also processed by DWT and QSVD. Afterward, the singular value matrix of the encryption watermark is embedded into the singular value matrix of the host image by the optimal scaling factor. Moreover, the values to balance imperceptibility and robustness are optimized with a genetic algorithm. It is shown that the proposed color image watermarking scheme performs well in imperceptibility, security, robustness and embedding capacity.

A Color Image Watermarking Approach Based on Synchronization Correction

Wang X., Xu H., Zhang S., Liang L., Niu P., Yang H.

Fundamenta Informaticae

2018

Vol. 158, nr 4

385--407

Digital watermarking has been proposed as an effective technology of copyright protection and content authentication, yet up to now, research on the robust watermarking against geometric attacks is still a challenging task. This paper presents a novel robust watermarking algorithm in nonsubsampled shearlet transform (NSST) domain using quaternion polar harmonic transform (PHT) and least squares support vector regression (LS-SVR), which is a recently developed geometric correction algorithm for digital color image. The major innovative works of the proposed approach lie in that (1) the NSST is applied to embed the watermark, which can provide the image function with nearly optimal approximation and employ fully the properties of human visual system (HVS), (2) the robust 2D transform, namely quaternion PHT is introduced to represent the characteristics of color image, and (3) the novel synchronous correction method is proposed using the excellent LS-SVR and quaternion PHTs, which can accurately estimate the geometric distortions parameters. In our experiments, we applied the proposed method to the standard color image test dataset, and the experimental results demonstrate that the proposed algorithm is not only invisible, but also robustness against common signal processing operations and geometric attacks.