Efficient and informative visualization of surfaces with uncertainties is an important topic with many applications in science and engineering. In these applications, the correct course of action may depend not only on the location of a boundary, but on the precision with which that location is known. Examples include environmental pollution borderline detection, oil basin edge characterization, or discrimination between cancerous and healthy tissue in medicine. This paper presents a method for producing visualizations of surfaces with uncertainties using points as display primitives. Our approach is to render the surface as a collection of points and to displace each point from its original location along the surface normal by an amount proportional to the uncertainty at that point. This approach can be used in combination with other techniques such as pseudocoloring to produce efficient and revealing visualizations. The basic approach is sufficiently flexible to allow natural extensions; we show incorporation of expressive modulation of opacity, change of the stroke primitive, and addition of an underlying polygonal model. The method is used to visualize real and simulated tumor formations with uncertainty of tumor boundaries. The point-based technique is compared to pseudocoloring for a position estimation task in a preliminary user study.Summary:
The system presented in this paper allows for the interactive creation of uncertainty visualizations of surface boundaries. The main visualization method uses point primitives to display the surface, displacing the points along a distribution functions according to the amount of uncertainty of the surface boundary. In addition to using point primitives, lines connecting the original and displaced surface positions can be used to make a fuzzy rendering of uncertainty and give more information about the surface location and range of uncertainty. In a similar vein a polygonal representation of the surface can be rendered with the point or line primitives to make the more certain surface locations look smooth and well defined, while areas of uncertainty have both the predicted, polygonal surface and the point based representation of where the surface might be. Opacity can also be added to any of these rendering techniques to enhance the interpretive quality of the visualization. A nice feature of the system is the flexibility of the point primitives which leave other rendering parameters free for the display of additional data or information such as pseudo-coloring age information. This pseudocolor can be augmented by decreasing the saturation in areas of high uncertainty.Categories:
Uncertainty, visualizing surface uncertainty, point-based graphics.Techniques:
point based display of surfaces with displacement based on uncertainty, opacity mapping, displacement based on probability density function,Bibtex:
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@InProceedings{ grigoryan:2004:PBPS, author = "Gevorg Grigoryan and Penny Rheingans", title = "Point-Based Probabilistic Surfaces to Show Surface Uncertainty", booktitle = "IEEE Transactions on Visualization and Computer Graphics", pages = "546--573", month = " September/October", year = " 2004", }