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.

• 该方案先将待嵌入的窄频带的浮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。