Real-time visualization with Volume Pro 500 Board
The ability to manipulate a display of a 3D volume data set in
real time on a monitor screen provides a very immediate way to
gain insight into the extents, shapes and relative spatial
orientations of structures. Dedicated computer hardware and
software is required to perform the volume rendering calculations
fast enough for real-time manipulation. Relatively low-cost
hardware is now becoming available which can be run on low-cost
We are currently using Mitsubishi Volume Pro 500 PCI board.
This board is capable of rendering volume data of 256 x 256 x 256
voxels at a rate of up to 30 frames per second. Ray casting is
done using a parallel projection algorithm. The board includes
hardware-assisted support for zooming, cropping planes, slicing,
multiple light sources and more, all calculated on the fly.
The principal limitation of this board for our visualization
effort is that it only supports parallel projections. The
Volume Pro board does not provide hardware support for
perspective projections, which are required to do real-time
'fly-thrus' of a volume data set.
We currently use a software application originally developed by Mike
Bailey at the San Diego Supercomputer Center and further developed
by our graduate student X. Wang, to visualize the
density distribution of the solar wind between the Sun and
Earth. These 3D volume result tomographic reconstructions
of heliospheric remote sensing data. Four shots are shown below.
The first indicates a typical volume covered by the tomography:
a sphere centered on the Sun with a radius of 1.5 AU. The
remaining three show views of a reconstruction of Carrington
rotation 1653. At the top-left a view from above the solar north
pole looking down on the solar equator is shown. The bottom
figures show side views (after zooming in on the center in the
In this case, Thomson scattering observations from photometers
on the two Helios spacecraft were used. This reconstruction of a
solar minimum period clearly shows the spiral structure of
corotating structures in the solar wind.