Topology visualization methods are very important for discovering the topology structure of the fluid fields. Among them, topology graph is a primary means, which can describe the topology relation among the critical points clearly. However, it is incapable of depicting the scope of the topology feature in the fluid field. As a basic property of topology feature, the scope property is important to investigate the fluid field and its time-dependent transformation. This paper presents a new method named topology Voronoi graph which is able to define the scope and describe the trend of one topology feature in the time-dependent vector field. First, we introduce the streamline distance to describe the mutual influence between any two points in the vector field. Then we can calculate the streamline distance of each point, with respect to the critical point it crossed, to define the feature region for the critical points in the vector field. Finally, we design an efficient topology Voronoi graph generation algorithm. The experiments on the wind field and the synthetic function data show that this method can enhance the structure visualization effects on the fluid field.%特征可视化能揭示流场的拓扑结构,是流场可视化的重要手段之一.传统特征可视化侧重于描述流场中各临界点间的拓扑关系,而较少重视各特征的区域范围.作为特征的重要属性,合理定义描述特征的有效影响范围,对于研究流场特征性质及其变化非常重要.为此,分析了平面流场拓扑特征,定义了流场典型特征的有效区域范围,提出了一种描述流场性质及变化的新方法--拓扑Voronoi图.该方法借鉴了传统Voronoi图区域分割的思想,针对流场矢量性特点引入了流线距离概念.然后在此基础上,与临界点方法相结合,量化给出了流场内各临界点的特征区域范围.设计了有效的拓扑Voronoi图生成算法.实验数据与合成数据测试表明:该方法能有效描述流场特征结构,对分析流场性质变化具有重要的意义.
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