Ji Guangfeng, Shen Han-Wei
The Ohio State University, USA.
IEEE Trans Vis Comput Graph. 2006 Sep-Oct;12(5):1109-16. doi: 10.1109/TVCG.2006.137.
Animation is an effective way to show how time-varying phenomena evolve over time. A key issue of generating a good animation is to select ideal views through which the user can perceive the maximum amount of information from the time-varying dataset. In this paper, we first propose an improved view selection method for static data. The method measures the quality of a static view by analyzing the opacity, color and curvature distributions of the corresponding volume rendering images from the given view. Our view selection metric prefers an even opacity distribution with a larger projection area, a larger area of salient features' colors with an even distribution among the salient features, and more perceived curvatures. We use this static view selection method and a dynamic programming approach to select time-varying views. The time-varying view selection maximizes the information perceived from the time-varying dataset based on the constraints that the time-varying view should show smooth changes of direction and near-constant speed. We also introduce a method that allows the user to generate a smooth transition between any two views in a given time step, with the perceived information maximized as well. By combining the static and dynamic view selection methods, the users are able to generate a time-varying view that shows the maximum amount of information from a time-varying data set.
动画是展示随时间变化的现象如何随时间演变的有效方式。生成高质量动画的一个关键问题是选择理想的视角，通过该视角用户能够从随时间变化的数据集中感知到最大量的信息。在本文中，我们首先针对静态数据提出一种改进的视角选择方法。该方法通过分析从给定视角生成的相应体绘制图像的不透明度、颜色和曲率分布来衡量静态视角的质量。我们的视角选择指标倾向于具有较大投影面积的均匀不透明度分布、在显著特征之间具有均匀分布的较大显著特征颜色区域以及更多可感知的曲率。我们使用这种静态视角选择方法和动态规划方法来选择随时间变化的视角。随时间变化的视角选择基于随时间变化的视角应显示方向的平滑变化和接近恒定速度的约束，使从随时间变化的数据集中感知到的信息最大化。我们还引入了一种方法，允许用户在给定时间步长内的任意两个视角之间生成平滑过渡，同时感知到的信息也最大化。通过结合静态和动态视角选择方法，用户能够生成一个随时间变化的视角，该视角展示了来自随时间变化数据集的最大信息量。
