摘要：为了更有效地进行多媒体数据的版权保护，提出了一种在真彩色宿主图像中利用奇异值分解实现的灰度水印嵌入的鲁棒算法。该算法首先利用奇异值的特征来对灰度水印图像进行编码预处理，编码后的水印信息存储为二值数字序列，并选择视觉掩蔽性高的宿主图像区域进行隐藏。为了保证水印的不可察觉性，该水印算法先提取宿主图像RGB彩色空间中的蓝色通道分量，然后选择其中具有高活动因子的图像分块作为水印的嵌入区域。用该算法对灰度水印图像进行处理，不仅实现了水印的盲提取，而且在保证隐藏灰度水印大容量生动信息的同时，对宿主图像的视觉效果影响很小。实验结果表明，该水印算法不仅较传统方法有更高的鲁棒性，而且灰度水印图像的提取结果受常见的图像处理攻击操作的影响非常小。

Abstract：In order to effectively protect the copyright of multimedia data, a novel digital color image watermarking algorithm based on singular value decomposition was presented in this paper. The watermark used in the algorithm is 8bits gray-level image which is used extensively in these days and includes more information than the binary image watermark. The scheme first encodes the gray-level watermark into the binary-value bit sequence using the singular value decomposition, and then embeds the encoded watermark into the region with high visual masking effect. In order to access the aim of the watermark’s imperceptions, a method which extracts the blue channel in RGB color space of the host image is adopted. The application of watermark encoding scheme makes our method achieve the goal of watermark blind-extraction and large quantity of vivid information’s hiding. Simulation results show that the proposed method is more robust than traditional methods. The watermarks extracted from the host image after different kinds of attacks that usually encountered in the course of image processing and transmission are still clear and their visual information are nearly lossless.