基于图像内容的局部化数字水印算法

本文提出一种基于DWT的CBWM局部化数字水印算法，该算法是利用图像中相对稳定的特征点来标示局部水印的嵌入位置，并在与每个特征点对应的局部区域内独立地嵌入水印 。这样。当只有部分图像时，仍能通过这些特征点来定位并检测水印。该算法中，局部水印的嵌入是通过将水印嵌入到局部图像小波变换域的低频空间的特征向量中，并且嵌
入的局部水印与特征向量两者正交。实验结果轰明．该算法对裁剪等各类攻击具有很好的鲁棒性。

An Image-Content-Based Localized Watermarking Algorithm

In this paper, we propose a new image-content-based localized watermarking algorithm CBWM based on DWT, which embeds wantermarks into the local regions of an image instead of the entire image. In order to improve the watermarking capability against attacks in the frequency area , we select some stable feature points in the image,and then use them to identify the locations where we insert the watermarks. When the image is cropped , the feature points in the remaining piece of the image will not change. And the embedded watermark is designed to be orthogonal to the feature vector of the low frequency space in the DWT area of the local image, which means that watermarking casting is image content dependent. Experimental results show that the proposed algorithm is very robust to various attacks, especially cropping.