一个基于DWT的自适应数字水印算法

An Adaptive Digital Watermarking Algorithm Based on DWT

本文提出了一个新的DWT域自适应数字水印算法。该算法利用小波域高、低频部分嵌入水印的优势互补特点,在载体图像的高频和低频子带分别嵌入相同水印来增强水印抵抗多种攻击的能力;水印的嵌入采用量化调制方式,其量化步长可根据人类视觉系统和载体图像的局部特点自适应地调整。此外,由于奇异值分解具有良好的性能,因而被用于高频部分水印的嵌入以提高其鲁棒性。实验结果表明水印具有良好的鲁棒性和不可见性,与相近算法相比,本文方法可以有效抵抗更多的攻击。

In this paper,a novel image-adaptive watermarking algorithm based on discrete wavelet transform（DWT）is proposed. The method embeds a watermark into high frequency and low frequency of the discrete wavelet domain resectively together in order to make the watermark more robust in many attacks. Watermark embedding is performed by means of quantization index modulation, the quantization step of which can be dynamically adjusted according to the local image characteristics and the human visual system. In addition, the singular value decomposition is applied to the watermark embedding in high frequency of the discrete wavelet domain because of its good performance. Compared with other similar watermarking algorithms reported in the literature, this method can give better image quality and is robust against more attacks.