一种基于相位相关拼接的数字水印分存算法

A digital watermarking sharing algorithm based on mosaic of phase correlation

数字水印分存基于秘密共享的思想,将原始水印信息分解成n份分存水印信息,获得其中部分的分存水印信息就能恢复出原始水印信息。提出一种基于相位相关拼接的数字水印分存算法。该水印分存方法首先对原始水印进行置乱,再将置乱后的水印分成有重叠区域的n份,分别嵌入到载体图像的n个不同分块中,水印提取之后,再用相位相关度算法来求分块水印间的偏移量。依据相位相关度算法,能精确计算出分块水印间的偏移量。据此确定出具有重叠区域的相邻分块水印。将相邻分块水印拼接完成后进行逆置乱,获取原始水印。仿真测试实验表明,该算法能有效抵抗平滑、噪声、滤波、剪切、JPEG有损压缩以及位平面去除等攻击。与其他数字水印分存方法相比,算法具有更强的的鲁棒性。

Digital watermarking sharing is based on the idea of the secret sharing. It divides the original watermarking information into n parts. When some parts are known, the original information can be recovered. This paper presents a digital watermarking sharing algorithm based on mosaic of phase correlation. The proposed algorithm scrambles the original watermark first and divides the scrambled watermark into n parts. Afterwards the algorithm embeds the n parts into n different fields of carrier image. After watermark extraction, the offsets among each pairs of watermark parts are calculated based on the phase correlation algorithm. All divided watermark pairs with overlapping can be generated from the offsets. The whole scrambled watermark is then reconstructed from these divided watermark parts. The original watermark is obtained after inverse scrambling. The experimental results deomonstrate that the scheme is robust enough to many attacks, especially to smoothing, noise, filtering, cropping, JPEG compression and bit plane cutting. Our algorithm has more robustness in comparison with previous digital watermarking sharing algorithms.