保持拓扑关系与几何特征的矢量地图水印处理方法

Method of Preserving Topology and Geometric Characteristics for Watermarking Vector Map

矢量地图描述了地物特征及其空间关系。在矢量地图中嵌入数字水印可能会改变其几何特征和拓扑关系,从而降低矢量地图的可用性。针对这一问题,提出一种保持拓扑关系与几何特征的矢量地图水印处理方法,通过顶点的最大允许扰动范围计算、嵌入水印后的顶点移位检测、以及基于同名点拓扑关联的顶点坐标调整等处理,保持拓扑关系和几何特征正确性。采用居民地面矢量数据进行数字水印嵌入与检测实验,嵌入数字水印后的矢量地图保持了正确的拓扑关系和几何特征,验证了方法的可靠性和有效性。

Vector map depicts the features of geospatial objects and their spatial relations. Watermarking in vector map may result in a change of the topology and geometric characteristics, which may reduce the usability of watermarked vector map. To solve this problem, a watermarking method for vector map is presented in the paper, which is based on the realization of maximum perturbation regions, the examining of dislocated vertices of watermarked vector map, and the adjustment of coordinates by using the same vertexes topologically associated. A comprehensive experiment of watermarking and detection of residential vector data is carried out. The results showed that the topology and geometric characteristics of the watermarked vector map are well preserved, which verifies the reliability and validity of the proposed watermarking method.