Cubrilles Statistical Volume Vis

Cuberilles Statistical Volume VisINF252 Visualization Final Project PresentationChristian Kehl

Design FocusCoupled interaction Statistics Volumestatistical 2D views (Avg/Max Intensity Proj.)Statistics per Dimension1D ray: Histogram, Profile, Semi-Variog.2D slice: Histogram, Semi-Variogram3D volume: HistogramConvolution responses; Histogram > PDFDesignDemoSpecificsReflection

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PDF: Probability Distribution Function2

Design Focus3D representation using Cuberilleswhy ? data sharing GPU 3D CPUGlyphing Cuberilles with Cubes or SpheresPreset Editor for Colour-Opacity changesLensing for Zooming; separated 3D-2D viewFocus: interaction & vis. mapping; sacrifice render quality (no render styles or shadows; simple shading)DesignDemoSpecificsReflection

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One-man group, so feature sacrifices and priorities need to be made!!!3

Implementation ChoicesDev Environment: Linux; hence Cross-PlatformJava OpenGL (JOGL); no SceneGraph avail.Shaders in GLSLUI: SWT (native UI on each system)distribution via web (Java webstart) or binaryGraphing library: SWT charttryouts with modern OpenCL list sorts failed ...DesignDemoSpecificsReflection4

DemoDesignDemoSpecificsReflection

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Specifics non-implemented featuresFocus+Context via lensingswitch perspective/orthographic proj.Dataset comparisonGlyphing: limited by render speedProbability distribution function (PDF)Convolution kernelsDesignDemoSpecificsReflection6

CuberillesOpenGL 2: triangle array too slow (call-bound); blending problemsOpenGL 3: geometry shader reduces to point callsOpenGL 4: instanced rendering (not impl.)Geometry shader description of cube simple, spheres demand more callsCube: 6 triangle patchesSphere (6 vert., 12 horiz. resolution): 72 triangle p.DesignDemoSpecificsReflection7

CuberillesDesignDemoSpecificsReflection8

12 yo laptop, GLES: 64x64x29Lab PC, Quadro K4200, GL3: 512x512x232

Alpha CompositionProblem: Render-order dependent compositiondepth peeling => small number of alpha layerstried pre-computed render orders (1 per bounding box corner): didnt really work ...Sorting: just points, not cube verticesSimple view-dependent sorting not interactiveParallel sorting improved speed reasonablyDesignDemoSpecificsReflection9

Alpha Composition

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common alpha composition with x-y-z render orderpre-computed, closest-corner render orderrender order computed each frame

Normal/Gradient VisualisationNormal: divergent per dimension & between positive/negative slope; defined 0-pointDesignDemoSpecificsReflection11

full colour spectrum ->colour-blind problemdivergent, too brightxy mapping+; z mapping -contrast-less; 0-value confusergood contrast, good highlights; confuser: N[0 0 1] = N[0 0 0]divergent between x-y-z:[magenta-blue-purple]

divergent to slope directionwith saturation:[high-mid-low] = [-1 0 1]

0-value confuser possible

V-1 = I-1

Geological DatasetsGeological facies datasets similar to CT (depict structure)statistical exploration can help to spot rock relationshipsDesignDemoSpecificsReflection12

porosity model depicts structure poorly

facies model depicts structure very well

Lessons learned ...Cubrilles: possible, but not advisable (modern GPUs do volume raycasting better)Statistics: helpful for exploring new datasetsLighting: highlights structure in volumes unexpectedly wellGPU sorting: did improved; still not comparable to CPUGradient/Normal Mapping: harder than it seems ...Volume Visualisation: its fun Lonely Rider not advisable a good team is better than the sum of its individuals ...

And: thank you for the time to update my OpenGL knowledge DesignDemoSpecificsReflection13

River Discharge

SANDSILTSearching for a summer orsemester job ?

Doing Volume Visualisationin Geology ?

then THIS may be for you!

Delft3D Delta Modelling: WebVis using WebGL / osgjs detailed, time-dependent, multi-variate VolumeVis teamwork with experienced 3D engineer as guide cool project, good team ... & getting in touch with petroleum

Contact: Simon J. Buckleysimon.buckley@uni.no

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