Craig M. Wittenbrink

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Visualized data often have dubious origins and quality. Diierent forms of uncertainty and errors are also introduced as the data are derived, transformed, interpolated, and nally rendered. In the absence of integrated presentation of data and uncertainty, the analysis of the visualization is incomplete at best and often leads to inaccurate or incorrect(More)
Uncertainty or errors are introduced in fluid flow data as the data is acquired, transformed and rendered. Although researchers are aware of these uncertainties, little has been done to incorporate them in the existing visualization systems for fluid flow. In the absence of integrated presentation of data and its associated uncertainty , the analysis of the(More)
volume rendering, compositing, ray tracing Volume rendering creates images from sampled volumetric data. The compute intensive nature of volume rendering has driven research in algorithm optimization. An important speed optimization is the use of preclassification and preshading. We demonstrate an artifact that results when interpolating from preclassified(More)
We present a new architecture for interactive unstructured volume rendering. Our system moves all the computations necessary for order-independent transparency and volume scan conversion from the CPU to the graphics hardware , and it makes a software sorting pass unnecessary. It therefore provides the same advantages for volume data that triangle-processing(More)
Environmental data have inherent uncertainty which is often ignored in visualization. Meteorological stations and doppler radars, including their time series averages, have a w ealth of uncertainty information that traditional vector visualization methods such as meteorological wind barbs and arrow glyphs simply ignore. We h a ve d e v eloped a new vector(More)
We present a graphics hardware architecture that implements Carpenter's A-buffer. The A-buffer is a software renderer that uses pointer based linked lists. Our pointerless approach computes order independent transparency for any number of layers with minimal hardware complexity. Statistics are shown for a variety of different scenes using a trace based(More)
As networking technology brings us into the information age, 3D and multimedia applications become more prevalent and the emerging norm. Improvements in communication infrastructure also allow us to explore the realm of group interaction and collaboration over the information superhighway. Our work focuses on providing a small group of geographically(More)
abstract Evaluating and comparing the quality of surface interpolants is an important problem in computer graphics, computer aided geometric design and scientiic visualization. We introduce geometric uncertainty as a measure of interpolation error, level of conndence or quality of an interpolant. Geometric uncertainty can be estimated as a scalar or a(More)