Craig M. Wittenbrink

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Visualized data often have dubious origins and quality Di erent forms of uncertainty and er rors 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)
Environmental data have inherent uncertainty which is often ignored in visualization. Meteorological stations and doppler radars, including their time series averages, have a wealth of uncertainty information that traditional vector visualization methods such as meteorological wind barbs and arrow glyphs simply ignore. We have developed a new vector glyph(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)
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)
Shirley and Tuchman’s projected tetrahedra approach is a fast algorithm for unstructured volume visualization, because it generates triangles that may be rendered by hardware acceleration. In this paper, I explore optimizations using OpenGL triangle fans, customized quicksort, memory organization for cache efficiency, display lists, and tetrahedral culling.(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)
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)
Volume rendering algorithms visualize sampled three dimensional data. A variety of applications create sampled data, including medical imaging, simulations, animation, and remote sensing. Researchers have sought to speed up volume rendering because of the high run time and wide application. Our algorithm uses permutation warping to achieve linear speedup on(More)