Roy Soumitra, Pal Arup Kumar
Department of Computer Science and Engineering, Dr. B. C. Roy Engineering College, Durgapur, West Bengal 713206, India.
Department of Computer Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand 826004, India.
R Soc Open Sci. 2017 Jun 28;4(6):170326. doi: 10.1098/rsos.170326. eCollection 2017 Jun.
Digital image watermarking has emerged as a promising solution for copyright protection. In this paper, a discrete cosine transform (DCT) and singular value decomposition (SVD) based hybrid robust image watermarking method using Arnold scrambling is proposed and simulated to protect the copyright of natural images. In this proposed scheme, before embedding, watermark is scrambled with Arnold scrambling. Then, the greyscale cover image and encrypted watermark logo are decomposed into non-overlapping blocks and subsequently some selected image blocks are transformed into the DCT domain for inserting the watermark blocks permanently. For better imperceptibility and effectiveness, in this proposed algorithm, watermark image blocks are embedded into singular values of selected blocks by multiplying with a feasible scaling factor. Simulation result demonstrates that robustness is achieved by recovering satisfactory watermark data from the reconstructed cover image after applying common geometric transformation attacks (such as rotation, flip operation, cropping, scaling, shearing and deletion of lines or columns operation), common enhancement technique attacks (such as low-pass filtering, histogram equalization, sharpening, gamma correction, noise addition) and jpeg compression attacks.
数字图像水印技术已成为一种很有前景的版权保护解决方案。本文提出并模拟了一种基于离散余弦变换（DCT）和奇异值分解（SVD）的混合鲁棒图像水印方法，该方法使用Arnold置乱来保护自然图像的版权。在该方案中，在嵌入之前，水印通过Arnold置乱进行置乱。然后，将灰度载体图像和加密的水印标志分解为不重叠的块，随后将一些选定的图像块变换到DCT域以永久插入水印块。为了获得更好的不可感知性和有效性，在该算法中，通过乘以一个可行的缩放因子，将水印图像块嵌入到选定块的奇异值中。仿真结果表明，在应用常见的几何变换攻击（如旋转、翻转操作、裁剪、缩放、剪切以及行或列的删除操作）、常见的增强技术攻击（如低通滤波、直方图均衡化、锐化、伽马校正、添加噪声）和JPEG压缩攻击后，通过从重建的载体图像中恢复出令人满意的水印数据，实现了鲁棒性。
