Chris Weigle

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An isovalue contour of a function of two complex variables defines a surface in four-space. We present a robust technique for creating polygonal contours of complex-valued functions. The technique, Contour Meshing, generalizes well to larger dimensions. CR Descriptors: G.1.5 [Numerical Analysis] Roots of Nonlinear Equations; G.1.6 [Numerical Analysis](More)
The need to compare surfaces occurs frequently in many scientific pursuits. Local comparisons can be quite difficult when the surfaces are placed side-by-side. But the two surfaces may intersect in complex ways if overlaid. Techniques have been previously developed for visualizing nested surfaces. The most successful of these apply opacity-modulated texture(More)
Although autoregulation of cerebral blood flow is well established, the response of cerebral capillary circulation to reduced cerebral perfusion pressure (CPP) is unclear. The objective of this study was to determine whether red cell flow velocity in individual capillaries of the cerebral cortex is maintained during acute decreases in CPP. Microcirculation(More)
Large datasets typically contain coarse features comprised of finer sub-features. Even if the shapes of the small structures are evident in a 3D display, the aggregate shapes they suggest may not be easily inferred. From previous studies in shape perception, the evidence has not been clear whether physically-based illumination confers any advantage over(More)
This paper describes a texture generation technique that combines orientation and luminance to support the simultaneous display of multiple overlapping scalar fields. Our orientations and luminances are selected based on psychophysical experiments that studied how the low-level human visual system perceives these visual features. The result is an image that(More)
ImageSurfer is a tool designed to explore correlations between two 3D scalar fields. Our scientific goal was to determine where a protein is located, and how much its concentration varies along the membrane of a neuronal dendrite. The 3D scalar field data sets fall into two categories: dendritic plasma membranes (defining the structure) and(More)
Acute hyperammonemia at normal arterial pH causes selective increases in midbrain blood flow in dogs. Unexpectedly, further increases occur with hypocapnia. We investigated whether metabolic acidemia and alkalemia modulate the distribution of ammonium across the blood-brain barrier and if, in turn, midbrain blood flow is effectively modulated. In dogs(More)
Commercial eye-gaze trackers have the potential to be an important tool for quantifying the benefits of new visualization techniques. The expense of such trackers has made their use relatively infrequent in visualization studies. As such, it is difficult for researchers to compare multiple devices – obtaining several demonstration models is impractical in(More)
We have developed a real-time experiment-control and datadisplay system for a novel microscope, the 3D-Force Microscope (3DFM), which is designed for nanometer-scale and nanoNewton-force biophysical experiments. The 3DFM software suite synthesizes the several data sources from the 3DFM into a coherent view and provides control over data collection and(More)