werner benger 1 and georg ritter 3 and simon su 4 and dimitris e. nikitopoulos 2 and eamonn walker 2...
TRANSCRIPT
DOPPLER SPECKLES –A MULTI-PURPOSE
VECTORELDVISUALIZATION TECHNIQUE
FOR ARBITRARY MESHESWerner Benger1 and Georg Ritter3 and Simon Su4 and
Dimitris E. Nikitopoulos2 and Eamonn Walker2 andSumanta Acharya2 and Somnath Roy2 and
Farid Harhad1 and Wolfgang Kapferer3
1Center for Computation and Technology, Louisiana State University, USA2Department for Mechanical Engineering, Louisiana State University, USA
3Institute for Astro- and Particle Physics, University of Innsbruck4Princeton Institute for Computational Science and Engineering
Outline
The Problem
The Approach
Application Examples
The Problem
Visualizing Vectors in 3D & 4D
The Approach
Splatting Technique: Drawing of Gaussian spots as billboard per vertex
Used for Volume Rendering of Unstructured Meshes
Gaussian splats in view plane – Efficiently done via OpenGL Point Sprites
Vector Speckle
Elongate along direction of vector in a field
1. Stretch
2. Orient
3. Offset
Vector Speckle - Stretch
Stretch according to Vector Magnitude
Freedom in various scaling factors and mappings (like vector arrows)
Compute Projection of Vector in View Plane
View-dependent shape – requires GL fragment shader
Vector Speckle - Orientation
View Plane
Vector Speckle - Offset
Free parameter to allow animation of display element
T=0.0
T=0.2
T=0.5
Doppler Effect
Physical Effect: movement of wave-emitting objects influences observed frequency
Known as sound of passing street cars: Movement to observer increases frequency Movement from observer decreases frequency
Light: Color change of moving objects Approaching - higher frequency – blueshift Escaping - lower frequency - redshift
Application Examples
1. Couette Flow (Analytic Vector field)
2. Microchannel Droplet (Uniform Grid)
3. Stirtank Fluid (Curvilinear Multiblock)
4. Galaxy Evolution (Particle System)
Couette Flow
VECTOR ARROWS DOPPLER SPECKLES
Couette Flow
STREAMLINES DOPPLER SPECKLES
Couette Flow
DOWN VIEW UP VIEW
Microchannel Droplet
FRONT VIEW BACK VIEW
Streamlines Enhanced
STREAMLINES SPECKLES ON STREAMLINES
Streamlines Enhanced
STREAMLINES SPECKLES ON STREAMLINES
Stir Tank
2088 Curvilinear Blocks
SIDE VIEW UP VIEW
Evolving Galaxies
16 Million particles, each representing one galaxy
Cosmological evolution over several billion years
300GB of raw data Velocity given for
each galaxy
Evolving Galaxies
Evolving Galaxies
Evolving Galaxies
Availability
Algorithms implemented and available in Vish – Visualization Shell Freely available for academic usage
Code development management: http://sciviz.cct.lsu.edu/projects/vish
Available via SVN in source code for registered users at http://vish.origo.ethz.ch/