Scientific Visualization By: Jesus Caban and Chi Chau

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.

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 ● Scientific 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

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.) Stereo Displays: Active Stereo: PolarizedAnaglyphic From NASA 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 HMD

“Trivial” Examples 2D plot –Matlab t = 0:0.01:5; y = sin(4*t); plot(t,y); 3D plot –Matlab [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

Other techniques 3D points XYZ ….…… Result: –A 3D object that we ca can visualize

Hardware Hardware for large data sets –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. Visualization by W. Benger, Simulation by AEI Potsdam

OpenGL Performer in Games OpenGL Performer is a powerful and comprehensive programming interface for developers creating real-time visual simulation and other performance-oriented 3D graphics applications. It simplifies development of complex applications used for visual simulation, manufacturing, simulation-based design, virtual reality, scientific visualization, interactive entertainment, broadcast video, architectural walk-through, and computer-aided design.

Performer Town: Visual Simulation scene This rural town environment was one of the first real-time databases ever seen on the RealityEngine. It was modeled by Wes Hoffman of Paradigm Simulation using the MultiGen database modeling tool and is explored using Perfly, the sample real-time application distributed with OpenGL Performer. The trees, parking meters, and street lights in this scene are flat textured polygons rotated to face the eyepoint each frame. The traffic signals are animation sequences and cycle between green, yellow, and red states automatically

GeoWall in Geo A good understanding of spatial relationships is a fundamental requirement in the study of the Earth Sciences. Traditional teaching methods have strongly relied on the 2D representations through maps and profiles that are occasionally augmented by physical models. Although most Earth Scientists have been trained to understand the 3D structure from such representations, the extrapolation requires spatial thinking skills that are difficult to learn and often form a stumbling block for students at the introductory level.

GeoWall Con’t The GeoWall mission is to broaden the use of scientific visualization tools for Earth Science research and education by the use of low cost virtual reality visualization devices. The current GeoWall hardware is based on Agave technology developed at the Electronic Visualization Lab

Software & Hardware Needed Software – image display for GeoWall OpenGL base, stereo pair, vpokescope, viewer, wallview Software – geometry display 2Space assistant, coanim, iView 3D etc Hardware – Projectors, Screens, Linear Polarization Glases, Circular Polarization, Projector Stackers, Graphics Boards and Stereo Cameras

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. - Data courtesy Nasa Langley Research Center

References