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The Hidden Face of Venus

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Mike Caprio edited this page Mar 6, 2019 · 32 revisions

Adapt the Open Source NASA Ames Stereo Pipeline for Radar Stereo Images

Hackathon Findings

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Background

Venus is a dim and scorched world of intense heat and volcanism, with temperatures hot enough to melt lead. Similar in structure and size to Earth, Venus spins slowly in the opposite direction of most planets; on Venus, the sun rises in the West and sets in the East, and one day lasts 243 Earth days! The planet has a thick, toxic atmosphere which traps heat in a runaway "greenhouse effect" and makes it nearly impossible to observe its hidden surface features.

The Magellan spacecraft, named after the sixteenth-century Portuguese-born explorer whose expedition first circumnavigated the Earth, was launched May 4, 1989, and arrived at Venus on August 10, 1990. Magellan's solid rocket motor placed it into a near-polar elliptical orbit around the planet. During the first 8-month mapping cycle around Venus, Magellan collected radar images of 84 percent of the planet's surface, with resolution 10 times better than that of the earlier Soviet Venera 15 and 16 missions.

A Venus surface image produced by the JPL Multimission Image Processing Laboratory by Eric De Jong, Jeff Hall, Myche McAuley, and Randy Kirk of the United States Geological Survey, and is a single frame from a movie released at a Magellan news conference.

Altimetry and radiometry measurements were also made, yielding information about the surface topography and electrical characteristics. Magellan's synthetic-aperture radar (SAR) imagery gave us glimpses through the planet's clouds that reveal its volcanoes and deformed mountains; and in recent years, Earth-based radar systems have filled in all the gaps that Magellan didn't catch on its mission.

Left and right facing radar images of Venus surface could be combined to produce accurate topographic maps. The open source NASA Ames Stereo Pipeline cannot handle radar stereo images. Can we adapt it to do so, create Digital Elevation Maps, and put them into OpenSpace? This paper on production of digital elevation models from stereo may be helpful!

What Is OpenSpace?

OpenSpace is free and open source interactive data visualization software designed to visualize the entire known universe and portray our ongoing efforts to investigate the cosmos. It contains the entire AMNH Digital Universe dataset, and dynamically fetches the latest data from myriad sources online every time it starts up.

Funded in part by NASA, OpenSpace brings the latest techniques from data visualization research to the general public. The software supports interactive presentation of dynamic data from observations, simulations, and space mission planning and operations. OpenSpace works on multiple operating systems, with an extensible architecture powering high resolution tiled displays and planetarium domes, and makes use of the latest graphic card technologies for rapid data throughput. In addition, OpenSpace enables simultaneous networked connections across the globe, creating opportunity for shared experiences among audiences worldwide. The OpenSpace project is led by the Science Visualization Group and Hayden Planetarium at AMNH in collaboration with dozens of institutions all across the globe, including top computational visualization groups at Linköping University in Sweden and University of Utah.

As noted above and below, we HIGHLY recommend that you download, install, and play with OpenSpace well before you come to attend the hackathon. You will save tons of time with setup and configuration that could otherwise be wasted during the short amount of time we have at the event.

OpenSpace is funded in part by NASA under award No NNX16AB93A. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Aeronautics and Space Administration.

OpenSpace is also funded in part by the Knut & Alice Wallenberg Foundation in Sweden and the Swedish e-Science Research Centre.

Solutions

The primary focus of this challenge is to look at the NASA Ames Stereo Pipeline (ASP) and see what can be done with it. The stereo equation with SAR data is different than for optical data and that is potentially an easy problem to fix with the Pipeline. The greater problem is that Magellan was done long before the ISIS software that gets data into the appropriate format for ASP was developed. To do things in ASP with Magellan one would need to figure out how to get the Magellan Full-Resolution Basic Image Data Record (F-BIDR) images, which are in a very strange projection and with a strange header label, into a format suitable for ASP.

Dr. Robert Herrick and his colleagues used mosaicked Magellan data, from full-resolution radar maps a.k.a. FMAPs, which introduces its own problems. Working with the BIDRs is challenging, but maybe there is a way to get the FMAP images into ASP?

Another possible approach could be to work with the left-right, opposite look SAR data, where Dr. Herrick recommends Mutual Information as a promising technique, rather than cross-correlation, for identifying match points. Adding this as an option in ASP would be very valuable. You can refer to his abstract on this particular approach.

If the ASP can be adapted, the next step would be to generate Digital Elevation Models (DEMs) for Venus and load them into OpenSpace's globebrowsing module to visualize these data sets.

Resources

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Challenge owner: Micah Acinapura

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