September 2, 2005  


New Tool for Computer Visualization in Stereo

A zoomin, with lots of pretty isosurfaces in log density, z=19.9. But that doesn’t really matter, since it’s beautiful and not scientific.
(Image courtesy of Matthew Turk)

Isosurfaces of Redshift 24.
(Image courtesy of Matthew Turk)

By Nina Adelman Stolar

The third Faculty member to join our Astrophysics group, Tom Abel (KIPAC) came to SLAC from Pennsylvania State University in September 2004. We were recruiting the best and brightest in Astrophysics to kick off KIPAC, our new joint venture with Stanford. Abel is an Associate Professor who spends 50 percent of his time in the Stanford Physics Department. His area of specialty is Computational Cosmology.

 The KIPAC mission is to harness theoretical and experimental physics communities, and bring their combined strengths to bear on some of the most challenging and fascinating problems in particle astrophysics and cosmology. As a theoretician, Abel is developing a new technique that incorporates experimental data and could be a powerful tool spanning diverse disciplines.

“I’m interested in the first stars, the first black holes, dust… anything that was the first of its kind in the Universe,” he said. Abel uses supercomputers to address these questions. His programs can display gasses and dark matter, demonstrating their movement and behavior.

This technique is used to build a complete physical description by solving the equations for all relevant physics involved. Therefore the computer display is an accurate representation of structure in the universe creating immense amounts of three dimensional data. One individual time snapshot may already be 10 gigabytes of data. A typical simulation may produce 10 to hundreds of these. Visualization and analysis of these multi dimensional datasets presents a unique challenge. “The extra dimension available in an immersive environment helps a great deal for this!” he adds.

In a curtained section of a small cluttered room in the Central Lab, two projectors are mounted on the back wall with polarizing filters in front of them. By donning a simple pair of matched polarized eyeglasses, the subject matter appears in three dimensions on a large screen. With this technique you can demonstrate how a blob of cells in a Petri dish grows—or how the universe began.

Looking for Large Datasets

“I’m curious about finding other people at the Lab and on campus with really large datasets to fine tune this technique,” Abel said after mentioning that some of the software he is using was developed by a couple of his friends. He is using the technology in his teaching and believes that it has applications in many fields. To demonstrate, he turns on the projectors and the screen shows green globs which look like, and turn out to be, cells in a Petri dish. This sample shows visually how cells in a Petri dish grow into a mice sperm.

Tom Abel projecting stereo images in the visualization lab.  
(Photo by Matthew Turk)

Abel’s informal style and soft spoken explanations have a way of working into your brain and before you can think too hard understanding breaks through like sunshine. After fiddling with the program, a cluster of stars appears on the screen. Watching this, I have the same dizzy sensation you get viewing the night sky in the dessert. He describes what is being shown: the bits of our galaxy are accurately represented with their real characteristics. They appear before you with the same relative size, colors and intensity they exhibit when we observe them directly.

Abel is an ordinary guy, with an extraordinary new tool for exploring large data sets by visually showing how the process/subject moves through time. For his students, this may be a commonplace method for gaining a deep understanding of the internal conditions of astronomical phenomenon and how they evolve. For those working with three dimensional data, this can become a new tool to include in their scientific toolbox.





The Stanford Linear Accelerator Center is managed by Stanford University for the US Department of Energy

Last update Thursday September 01, 2005 by Chip Dalby