一种小波变换域上的高鲁棒灰度水印

为了提高灰度水印抵抗滤波，加噪等常见攻击以及几何攻击的能力，提出了一种小波变换域上的高鲁棒水印方案。首先对灰度水印提出了一种新颖的数据压缩方法，并且从中提取出用于水印同步的参考比特。对于受到几何攻击的水印图像，提出了在低频子带上使用图像的主轴和边缘轮廓以获得旋转和缩放参数，从而能准确快速地恢复图像。同时在中频子带上采取了一种对参考比特进行高效匹配的办法来进一步实现水印的同步。实验表明除了一般图像处理之外，对于几何变形攻击本方案具有很好的鲁棒性。

A HIGH ROBUST GRAY LEVEL WATERMARKING SCHEME ON THE DWT DOMAIN

In order to improve the robustness of the gray level watermarking against common attacks such as filtering, adding noise and geometric distortion,this paper presents a high robust watermarking scheme on the DWT domain. We first propose a new data compression method for the gray level watermark and the reference bits used for synchronization are extracted from it. For the corrupted image by the geometric attacks ,we propose using the principal axis and the edge of the image in the low frequency sub-band to obtain the rotation and scaling parameters, so that the watermarked image can be recovered accurately and efficiently. And we adopt an effective matching method for the reference bits in the middle frequency sub-bands to achieve synchronization further. The experimental results demonstrate our proposed scheme is especially robust against the geometric attacks except for the common image processing.