Scientific Visualization

What is Scientific Visualization? Visualization for scientific computing, shortened to scientific visualization, was coined in 1987 and refers to the science or methodology of quickly and effectively displaying scientific data. 1987 NSF report: “Visualization in Scientific Computing” Formal name given to the field in computer science that includes user interface, data representation and processing algorithms, visual representations and other sensory presentation such as sound or touch. www.caida.org

Motivation In computational science we can use distributed computers and powerful clusters to simulate complex and realistic problems. It is difficult for the human brain to make sense out of the large volume of numbers Can we enhance and improve scientific productivity by utilizing human visual perception and computer graphics techniques? What can we do with the resulting numbers, formulas and data?

Scientific Visualization vs. Data Visualization graphical representations from the results of mathematical models, computations and simulations Involves research in computer graphics, image processing, high performance computing, and other areas It's not just a pretty picture or animation Data Visualization: More general term Implies treatment of data source beyond science and engineering, such as financial, business data, etc. Visualization is not only looking into a pretty picture… understanding of the data been able to analyze and interpret data Spot Noise http://www.llnl.gov/graphics/spot.html

Applications Used in: Engineering Computational Fluid Dynamics Simulation Medical Imaging Geospatial Ground Water Modeling Oil and Gas Exploration and Production and more…

Concepts associated with Visualization Personal visualization: analyze results, graphics in your PC. High-resolution displays: visualization of large-data sets. Immersive visualization: an environment where the user is immersed in the computer generated 3D graphics. Collaborative visualization: two or more users visualize the same data using different displays.

Concepts associated with Visualization (cont.) From NASA Stereo Displays: Active Stereo: Polarized Anaglyphic Holographic/Auto-stereoscopic displays multiple viewpoints at the same time Head-mounted displays two small monitors integrated into a headset which stimulate a large part of the user's field of view www.actuality-systems.com HMD

“Trivial” Examples 2D plot 3D plot Matlab t = 0:0.01:5; y = sin(4*t); plot(t,y); 3D plot [x,y] = meshgrid(-2:.1:2, -2:.1:2); z = x .* exp(-x.^2 - y.^2); mesh(z)

More advance example Animation in Matlab From http://www.oc.nps.navy.mi

Other techniques 3D points Result: X Y Z 101.32 98.2 43.2 102.01 46.4 …. … Result: A 3D object that we ca can visualize

Hardware Hardware for large data sets Stereo Visualization Supercomputer Clusters with commodity hardware Stereo Visualization ImmersaDesk Do we need supercomputers? What about Nvidia/ATI video cards in a PC or cluster?

Some Visualization Tools

Amira in Medical Advanced 3D visualization and volume modeling tool to process 3D data sets It allows you to gain detailed insight into your data. Graphics hardware support is utilized to display even very large data sets at interactive speed It mainly use in visualize 3D images data such as CT, MR, confocal, microscopy

The image depicts a surface model of the human head and the brain created from an MRI data set. Amira provides a "realistic" transparency mode for surface display (outer surface). Arbitrary fields can be mapped onto the surface (inner surface).

General relativistic simulation of gravitational energy General relativistic simulation of gravitational energy. Visualization by W. Benger, Simulation by AEI Potsdam

Designing Video Games

Vis5D - Weather Vis5D is a system for interactive visualization of large 5-D gridded data sets such as those produced by numerical weather models. One can make isosurfaces, contour line slices, colored slices, volume renderings, etc of data in a 3-D grid, then rotate and animate the images in real time. There's also a feature for wind trajectory tracing, a way to make text anotations for publications, support for interactive data analysis, etc.

FieldView – Fluid Dynamics FieldView is the World's Leading Post-processing and Visualization for Computational Fluid Dynamics

It illustrates the Velocity profile within an Engine Block

This is one of a series of images used by Lockheed Martin at the 1997 Paris Air Show.   An animation was created with FieldView, and projected onto a scale model of an F22 aircraft.

Pressure contours and velocity vectors on an F18 Pressure contours and velocity vectors on an F18. - Data courtesy Nasa Langley Research Center

References www.ssec.wisc.edu/~billh/vis5d.html www.amiravis.com www.sgi.com www.ilight.com www.geowall.org