一种基于余数判决的数字水印算法

本文给出了一种新型的鲁棒水印算法.首先选择一个混沌映射来置换水印数据和载体图像,以取得很好的置换效果.与现有其它空间域算法不同,本方案不直接修改单个象素的灰度值,而是根据提出的严格余数条件,重新设置载体图像象素间的灰度关系以实现水印数据的嵌入.并根据余数判决准则,利用基于空间域的纠错技术进行水印提取.仿真实验表明,该水印算法在保证载体图像质量的同时,具有较强的鲁棒性:在用JPEG将载体图像压缩到27.4%时仍能提出可识别的水印信息,并且能有效地抵抗加性高斯白噪声的干扰,在同步条件下对剪切、缩放、旋转等几何攻击也具有较好的鲁棒性.

A Watermark Algorithm Based On Remainder Decision

A novel robust watermarking scheme is proposed,in which a permuted watermark is embedded into a permuted image.We use a chaotic map to permute the image and the watermark data.and embed the watermark by resetting the relationship of the pixels instead of changing the pixels individually.A novel idea of remainder decision and a spatial based error correcting is realized with good performance in the extracted phase.The watermark embedded to the image is imperceptible and the extracted watermarks are still recognizable when JPEG compression ratio reaches 27 4% or after severe zero mean AWGN pollution.If well synchronized,this algorithm can also have good robustness to geometrical attacks such as cropping,scaling and rotating.