矢量地图数据数字水印抗拼接算法

地图拼接是矢量地图数据中的一种常见处理方式。为了正确提取水印信息,需要从拼接后的地图中确定出水印嵌入区域。利用水印嵌入后坐标点尾部数据分布发生变化的特点,提出了一种基于分布拟合检验的抗拼接算法。该算法利用四叉树算法将地图分成多个区域,然后利用单样本K-S检验判断每个区域内的坐标点尾部数据是否服从均匀分布,最终确定出水印嵌入区域。实验表明,该算法能够达到提取水印嵌入区域的目的。

The Watermarking Algorithm against Map Joint for the Vector Map Data

Map joint is a common data processing style of the vector map data. To extract the watermark correctly the embedded region should be extracted first from the jointed map. According to that the distribution of the mantis￣sa of the point coordinates will be changed while the watermark is embedded into it a new algorithm against map joint is proposed based on the distribution fitting test method. Firstly the map was divided into pieces by using the quadtree method then checked each piece by using K￣S sample test method to judge whether the distribution of the mantissa data of the points in the piece was distributed evently and finally the watered region was extracted. The experiment results indicated that the algorithm was available.