基于平行坐标主维度的多变量传递函数设计方法

摘要

为解决多变量体数据高效绘制时操作复杂、不易分析和表达的问题，将平行坐标与交互操作应用到传递函数设计中，并通过引入平行坐标主维度概念提出一种平行坐标与传递函数曲线相结合的设计方法。针对目前基于平行坐标的高维传递函数设计方法不灵活、调节烦琐的问题改进强度梯度直方图，并提取主维度数据特征；实现平行坐标自适应范围选择并进行指导性范围调节；把满足平行坐标各维度条件的采样点空间位置映射至主维度，提取数据范围实时生成传递函数曲线。实验结果表明，该方法能有效地降低高维传递函数设计的复杂度，提高传递函数调节灵活度，在实现实时交互的同时还可有效地增强绘制效果。%Considering the operation complexity, analysis and representation difficulty in the multivariable vol-ume data effective rendering, parallel coordinates and interaction are applied to the transfer function design; We introduce the concept of parallel coordinate prime dimension (PPD) and present a method for transfer function design which combines the parallel coordinate with transfer function curves. As the high dimensional transfer function design based on parallel coordinates is not flexible and needs tedious regulation, we extract the feature of PPD using improved intensity-gradient histograms and propose adaptive range selection in parallel coordinate to guide the range adjustment. Mapping the spatial position of sampling points which satisfies the range of each di-mension into PPD, extracting the data range and generating transfer function curves in real time. The experimen-tal results show that our approach can reduce the complexity of the design of high dimensional transfer function, improve the flexibility of transfer function regulation, and enhance the rendering result effectively.