基于二维工程图的数字水印扩频算法

Spread Spectrum Digital Watermarking Algorithm Based on Two-dimensional Engineering Graphics

针对二维工程图的特点提出了一种数字水印方案.该方案先将待嵌入的窄频带的水印信号扩频为宽频带的伪随机序列,然后再以伪随机序列为依据对二维工程图中直线实体的长度作相应的修改.检测水印时先进行同步操作,再对伪随机序列解扩进而得到水印存在与否的一种可信度结果.实验结果表明该方法对均匀缩放、旋转及平移等几何攻击,增加攻击等具有完全的健壮性;对于删除攻击具有很强的健壮性.

A digital watermarking scheme is presented according to the characteristics of two - dimensional engineering graphics. Narrowband watermarking information is spread into wideband pseudo - random code before being embedded by modifying the scale of the distance between vertexes in two - dimensional engineering graphics. If the visual effect is the same, this scale will not be changed because it is a whole characteristic. This scheme is very robust against the attack such as rotation, moving, equal scaling and so on ,which is illustrated by the result of the experiment.