引入模糊理论对流场特征的描述,提出了一种流场特征区域描述与提取算法.通过采用模糊理论对流场特征区域进行描述,从基本属性Φ、衍生属性γ、关联属性Π 这3 个层次建立了测度规则,然后对各规则分析建立了相应的特征向量,并基于特征向量偏差给出了模糊测度隶属度的确定方法.理论分析表明,该描述与提取算法在最小平方和准则下是对流场区域的最优模糊划分,并具有良好的划分性质.实验结果表明,与传统的提取方法相比,该方法能够更准确地提取各种流场的典型特征区域,既可以有效地支持流场特征强度变化的定量分析,又易于设计转换函数,从而有效地解决3D 流场可视化存在的遮挡和混淆问题.

This paper presents a method to describe and extract the general feature structures based on the fuzzy theory. This paper first builds some fuzzy measure rules with three levels (the basic property Φ, the derived property γ , and the associated property Π ). With the aid of measure rules, the feature vectors are established for fuzzy membership calculation and the feature region extraction. The analysis demonstrates that this method can obtain the optimal division of the flows on the principle of the minimum square sum. Further, the experiments show that the extent of typical flow structures extracted by this method are more effective than existing methods. In addition, the transfer function can be more flexible in design to avoid the cluttering and occlusion problems, which must be solved when visualizing 3D flows.

国家自然科学基金(60873120, 60773020, 60970094); 国家重点基础研究发展计划(973)(G2009CB723803); 国家高技术研究发展计划(863)(2009AA01Z301)