London Meeting, April 1998 - home page
Use of GIS in Determining Valley
Origin on Mars
K.L. Tanaka (ktanaka@flagmail.wr.usgs.gov),
J.M. Dohm, J.H. Lias & T.M. Hare
USGS, 2255 North Gemini Dr., Flagstaff, AZ 86001, USA.
The Pathfinder mission made use of a unique capability to rapidly
generate and interactively display three-dimensional photo-realistic virtual
reality (VR) models of the Martian surface. The Stereo Pipeline, an automated
machine vision algorithm, produces dense range maps of the near visible
field by matching features in the left and right IMP camera images
using the known camera geometry. The resulting range maps are
then projected into a three-dimensional model as a connected polygonal
mesh. IMP images or color composites are then overlaid onto
the mesh as textures to provide photo-realism. Upon receipt at JPL mission
control, IMP images were shipped to NASA Ames Research Center via internet
where models were computed and then shipped back to JPL for display.
The time from receipt of image data to display of complete models was less
than 30 minutes. The VR models were viewed interactively using MarsMap,
an interface that allows reprojection from any perspective driven by a
standard three-button computer mouse. Rapid rendering of the scene
allows the user to move smoothly though the interactive model environment.
The model can be viewed on a monitor either mono or stereoscopically, or
using a head-tracked VR display. The VR model also incorporates graphical
representations of the lander and the sequence and spatial locations of
rover data. Graphical models of the rover show the rover’s position at
the end of each sol and the rover’s traverse track can be displayed.
Images taken by Sojourner are projected into the model as two-dimensional
"billboards" to show the proper perspective of these images. Distance
and angle measurements can be made interactively within the model using
a mouse-driven three-dimensional cursor and a point-and-click interface.
The VR model was used to make detailed measurements of surface features,
such as wind streaks and rock size and orientation, that are difficult
to perform using two-dimensional images, as well as to plan and archive
rover activities.
Extra-terrestrial
Mapping Home Page
Comments to Dr. Randy Kirk
This page updated: 28 January, 2002, by Mark
Rosiek
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