School of Communication and Information Engineering, Shanghai University, Shanghai, P.R. China.
Shanghai Institute of Intelligent Electronics and Systems, School of Computer Science, Fudan University, Shanghai, China.
Math Biosci Eng. 2019 May 28;16(5):4788-4801. doi: 10.3934/mbe.2019241.
Image watermarking focuses on hiding secret data into the cover image imperceptibly to protect the copyright of the original image. In this paper, we propose a new framework of robust digital watermarking for color images using combined embedding techniques of Discrete Fourier Transform (DFT) and Dual Tree Complex Wavelet Transform (DTCWT). The cover image is first divided into Y, U and V channels. The Y channel is then transformed by DFT and partitioned into the ring shapes. With an embedding key, we generate pseudo-random patterns to represent the watermark. These patterns are also transformed and partitioned. The watermark represented by the selection of patterns is then embedded into the rings of the DFT coefficients. We further embed a rectification watermark into the U channel, in which DTCWT is applied to achieve a capability of geometric distortion resilience. On the recipient's side, the detection and extraction of watermark can be successfully done. Compared with previous schemes, the proposed method is better on preserving the image quality. Meanwhile, the robustness against typical attacks is also stronger.
图像水印技术主要通过将秘密数据隐藏在不可察觉的载体图像中来保护原始图像的版权。本文提出了一种新的使用离散傅里叶变换（DFT）和双树复小波变换（DTCWT）相结合的嵌入技术的彩色图像稳健数字水印框架。先将载体图像分为 Y、U 和 V 三个通道，然后对 Y 通道进行 DFT 变换并划分为圆环形状。通过嵌入密钥生成伪随机图案来表示水印，这些图案也进行了变换和分区。然后，根据图案的选择将表示水印的图案嵌入 DFT 系数的圆环中。我们进一步将校正水印嵌入 U 通道中，在 U 通道中应用 DTCWT 以实现抵抗几何失真的能力。在接收方，可以成功地进行水印的检测和提取。与以往的方案相比，该方法在保持图像质量方面表现更好，同时对典型攻击的鲁棒性也更强。
