Optimizing Volume Rendering Based on Field Topology Analysis

体可视化已经成为各个学科中不可或缺的方法，用于探索嵌入在大规模采样或模拟3D数据集中的体对象的内部结构和复杂行为。虽然基于硬件的加速机制的出现使用户能够以交互方式可视化这些体积，但其数据大小的快速增加使得难以充分调整传递函数并重复评估所得图像。在这项研究中，我们利用三维场拓扑分析，以优化传递函数，旨在体数据挖掘。传统的基于Reeb图的方法来描述三维表面的拓扑特征进行了扩展，以捕获的体积场的拓扑骨架。基于以超Reeb图形式表示的分析结果，提出了两条设计直接体绘制颜色/不透明度传递函数的原则。所提出的方法的可行性研究进行分析的三变量函数，大规模的4D模拟数据集从原子碰撞研究，和CT扫描的牙齿数据集。

Volume visualization has served as an indispensable methodology in various disciplines for exploring the inner structures and complex behavior of volumetric objects embedded in large-scale sampled or simulated 3D datasets. Although the advent of hardware-based acceleration mechanisms enables the user to visualize such volumes interactively, the rapid increase in their data size makes it difficult to adjust transfer functions sufficiently with repeated evaluation of resulting images. In this study, we take advantage of a 3D field topology analysis to optimize the transfer functions aiming at volume data mining. The conventional Reeb graph-based approach to describing the topological features of 3D surfaces is extended to capture the topological skeleton of a volumetric field. Based on the analysis results, which are represented in the form of hyper Reeb graphs, we proposed two principles to design appropriate color/opacity transfer functions for direct volume rendering. A feasibility study of the proposed methodology is performed with analytic trivariate functions, a large-scale 4D simulated dataset from atomic collision research, and a CT scanned tooth dataset.