一种基于小波变换域的数字水印算法

Digital watermarking algorithm based on the wavelet transform domain

水印的鲁棒性是目前数字水印研究的热点,设计鲁棒水印的重要性在于,即使含有水印的多媒体信息遭到了试图去除水印的攻击,例如压缩和加噪,也能够完全检测出其中所嵌入的水印,因而鲁棒水印在数字产品版权保护中具有十分重要的意义.文中研究了基于小波变换域的数字水印算法,通过将原始图像进行3级小波分解,然后选取中频带嵌入数字水印,通过定义小波系数与水印嵌入强度因子之间的函数关系,提出了一种自适应于原始图像特征的数字图像水印算法.实验结果表明,该算法对JPEG压缩、剪切、中值滤波、加噪等具有较好的鲁棒性.

The robustness of digital watermarking is a research hotspot at present. To protect the copyright ownership of digital products, it is important to design a robust watermark that withstands attacks on the watermarked multimedia even after attempts are made to remove them using methods such as compression or noising, in this point of view, robust watermarking possess very important significance. Studied here in a digital watermarking algorithm based on wavelet transform domain. By using the wavelet transform, the image was processed is a three-layer decomposition and then the wavelet coefficients of the middle layer were chosen to embed the watermarking. Defining a function between the embedded watermarks strength factor and the wavelet coefficients, led to an image-characteristic adaptive digital watermarking algorithm. Experimental results show that it is a highly robust algorithm against JPEG compression and cropping, median filtering and noise adding.