Robert H. Wolfe

Interactive visualization of 3D seismic data: a volumetric method

The authors demonstrate the utility of examining seismic data with a volumetric scheme, whereby a synoptic view of the interior of the data volume is possible before conventional interpretation. High-amplitude seismic events, representing reflections from subterranean surfaces, are transformed to color pixels, and the resulting 3-D images reveal the structure of the geological layers. Such morphological features as hills, valleys, and faults are apparent indicating that the approach could prove useful for identifying potential oil reservoirs. The authors implement the technique on a personal computer to produce displays of similar quality, but they find that the construction of the 3-D images is too slow for reasonable interactivity. However, with the addition of a parallel-processing accelerator, a personal-computer-based workstation would be feasible for this kind of 3-D visualization and interpretation.<<ETX>>

Deep view: high-resolution reality

We have designed the Deep View visualization system, which consists of a Linux cluster that performs computations to produce 3D geometry, renders the geometry to produce 2D pixels, and then transfers the pixels to be displayed on the T221 display (or video wall). We accelerate the pixel transfer operations using IBMs Scalable Graphics Engine (SGE). We drive high-resolution displays at interactive frame rates using our cluster and the SGE. The SGE is a network-attached frame buffer capable of double buffering up to 16 million pixels. It routes incoming pixels from multiple sources to the appropriate locations in its frame buffer and then transfers the composited result to the T221 display using digital video interface (DVI) output. In total, the SGE can accept up to 16 input links and can drive as many as eight synchronized DVI outputs. In addition, it can time interleave image pairs from its frame buffer to effect time-division stereo. In the current Deep View configuration, the rendered pixels are sent by each node in the cluster to the SGE over a Gigabit Ethernet link, and we use four of the synchronized DVI outputs to drive the T221 at full resolution.

Visual revelations from silicon ab initio calculations

The use of volumetric rendering for interpreting the computed electronic structure of solids is discussed. The structure, manifested as an atomic-scale 3-D electronic charge density, is computed from a pure mathematical model. The mathematical technique represents a class of ab initio computations that predict the atomic structure by solving the equations of quantum mechanics, wherein all configuration parameters except the atomic number are under the analysts control. Some physics aspects of electronic structure of solids are reviewed. The use of this visualization technique to interpret the computations for silicon with an oxygen impurity and for room-temperature silicon is described.<<ETX>>

A visit to the dresden frauenkirche

The Frauenkirche was destroyed when Dresden was bombed by the Allied forces February 13-14, 1945. The church is now being reconstructed in an effort led by the Foundation for the Reconstruction of the Frauenkirche. The VRDECK software package developed at the IBM T. J. Watson Research Center was used to view and walk through a model created from the original church plans. A Polhemus tracker and a custom-built joystick using the Logitech 3D mouse were used for six-degree-of-freedom input to the application. The interactive fly-through of the church is in an immersive environment. One can navigate around the model wearing a head-mounted display, sitting in front of a standard monitor, looking at a stereo image produced on a stereo monitor, or standing before a projection screen displaying a stereo image of the scene. The system was developed for and exhibited at the IBM booth in the CeBIT fair in Hannover, Germany in March 1994 with funding from IBM Germany.

A form-factor method for determing the structure of distorted stars

The equilibrium equations of a uniformly rotating and tidally distorted star are reduced to the same form as for a spherical star except for the inclusion of two form factors. One factor, expressing the buoyancy effects of centrifugal force, is determined directly from the integrated structure variables. The other factor, expressing the deviation from spherical shape, is shown to be relatively insensitive to errors in the assumed shape, so that accurate solutions are obtained in spite of the use of ana priori shape. The method is employed by adding computations for the factors to an existing spherical model program. Upper Main Sequence models determined by this method compare closely with results from the double approximation method even for critical rotation and tidal distortion.

Exposure time for space-borne IR spatial interferometer

A mathematical analysis is performed to determine the relationship between the signal-to-noise ratio and the exposure time for an orbiting ir heterodyne spatial interferometer. The analysis includes consideration of the transformation of the interferogram to obtain the source angular intensity distribution so that the signal- to-noise ratio pertains to the angular distribution rather than to the interferogram. The analysis is applied to a number of known ir sources. The results presented show that an interferometer with a 30-m baseline using half-meter telescopes should be able to image a source such as IRC + 30219 with a signal-to-noiseratio of 10 in a total exposure time of less than an hour.