CADIP Information Visualization Work: SFA - PowerPoint PPT Presentation

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CADIP Information Visualization Work: SFA

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David S. Ebert Computer Science & Electrical Engineering Department University of Maryland Baltimore County ebert_at_.umbc.edu Christopher D. Shaw – PowerPoint PPT presentation

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Title: CADIP Information Visualization Work: SFA


1
CADIP Information Visualization Work SFA
  • David S. Ebert
  • Computer Science Electrical Engineering
    Department
  • University of Maryland Baltimore County
  • ebert_at_.umbc.edu

Christopher D. Shaw Computer Science
Department University of Regina cdshaw_at_acm.org
2
Talk Outline
  • Background
  • Visualization Goals and Challenges
  • SFA Overview
  • Procedural Shape Visualization
  • Results
  • Recent Work with SFA
  • New Features
  • Interactive Lens Visualization
  • Future Directions

3
Background Introduction
  • Visualization
  • Transforms the abstract and symbolic into the
    geometric
  • Harnesses the human perception system (visual?)
  • Glyph-based Volume Rendering
  • Advantages of volume rendering
  • Encodes multidimensional and multivariate
    information

4
Visualization Goal Strategy
  • Goal
  • Effectively convey information to the user
  • Increase the quantity and clarity of the
    information
  • Display only as much information as is
    perceptually understandable
  • Strategy
  • Use perceptual cues to aid understanding of
    multidimensional and multivariate data

5
Interface Goal Strategy
  • Want 3D User Interfaces that are as easy to use
    as the WIMP style
  • Use 3D Input devices
  • Exploit 3D perception with animation
    interaction
  • Enable fine manipulation
  • Avoid user pain and fatigue

6
Challenge
  • Rate of Information Increase Greater than Screen
    Resolution Increase
  • Rapid increase in number of information sources
  • Bandwidth of sources increasing
  • Dimensionality increasing

7
Solutions
  • More Effective Visualization Techniques
  • Effective Use of Human Perception
  • Utilize visual perception characteristics
  • Add shading cues stereopsis to increase
    pre-attentive 3D perception
  • Utilize proprioception - bodys innate sense of
    its position in space

8
Perceptive Senses Available
  • Utilized in Near Term
  • Visual
  • 3D Spatialization
  • Volume / Size
  • Color
  • Shape (curvature)
  • Opacity
  • Texture
  • Haptic
  • Experimental
  • Proprioception
  • Auditory
  • Olfactory
  • Ergonomics Issues
  • Pain Fatigue

9
Our Glyph-based Visualization System SFA
  • Minimally-Immersive VR Interface
  • Multidimensional Multivariate Data
    Visualization
  • Utilizes Many Perceptual Cues

10
SFA System Features
  • Glyph Rendering
  • Data dimensions mapped to glyph attributes
  • Two-handed Interaction
  • Stereo Viewing
  • Multivariate, Multidimensional Time-varying Data
  • Regular and Irregular Grids

11
Rendering Within SFA
  • Visualizable Parameters
  • Location (3)
  • Color (1-3?)
  • Transparency (1)
  • Size (1-3)
  • Shape (1-14)
  • Surface Detail (1)

12
Perceptual Cues Used
  • Shape / Texture
  • Spatialization
  • Color
  • Volume / Size
  • Proprioception
  • Stereopsis

13
Minimally-ImmersiveUser Interface - Fishtank VR
  • Access to environment
  • Collaboration possible
  • Low cost (lt 10K)
  • Stereo viewing
  • Two-handed interaction
  • 3-space trackers with buttons
  • Each hand has a distinct role
  • Left hand sets up context
  • Right hand performs fine manipulation

14
Two-Handed Minimal Immersion
  • Left Hand
  • Position and orientation of volume
  • Selection of drawing context from 3D hierarchical
    menu
  • Right Hand
  • Volume subsetting
  • Probe data volume
  • Interactive lens visualization
  • Takes Advantage of Proprioceptive Sense
  • Hold Volume in 1 Hand, Operate on it with Other
  • Hands Form a Kinematic Chain (Guiard)
  • Left hand is base link, right hand operates
    relative to it Left is low frequency, Right is
    high frequency

15
Scientific Visualization Results
  • Application
  • Solar Magnetohydrodynamics Simulations
  • Performance
  • 2000 glyphs at interactive rates on an Indigo2
    High Impact

16
Information Visualization
  • Visualize High Dimensional Abstract Data Spaces
  • Examples
  • Document similarities (50,000 dimensions)
  • Database query routing, retrieval of meta-data
  • Financial data
  • Document Corpus Management
  • Information analysis, not just retrieval
  • Goals identify trends find anomalies, themes

17
Results
  • Visualization of Wall Street Journal Corpus SFA
    Results IVEE Results

18
Shape Visualization
  • Utilizing Pre-attentive Ability to Understand
    Shape (Parker et al.)
  • Shapes Shouldnt Detract from Spatialization
  • Intuitive Shape Mappings (curvature)

19
Parameterized Procedural Shape Visualization
  • Automatic Generation of Shapes for Data
    Visualization
  • Map Data Range to the Parameter Range
  • Easy
  • Supports continuous data ranges
  • Parameterization generates a visual order
  • May be very slow to generate shapes

20
Parameterized Procedural Shape Visualization
  • Exploring Three Approaches
  • Fractal Detail
  • Vary surface roughness from smooth to mountainous
  • Data value determines amount of fractal
    perturbation to the surface
  • Superellipsoids
  • Implicit Surfaces

21
Superquadrics - Superellipsoids
  • Introduced to Graphics by Barr in 1981
  • Extends Quadric Surfaces
  • With two exponents that control the overall
    roundness or pointiness of the shape.

22
Superellipsoids

23
Perception of Superellipsoid Shapes
  • Just Noticeable Difference Experiment Completed
    (Chris Shaw)
  • Both Exponents Changed Together
  • Result 21 Superellipsoid Shapes
    Perceivable

24
Scientific Visualization -Solar Wind MHD
Simulation
  • Opacity j vorticity
  • Shape j velocity -1
  • convex positive velocity
  • diamonds zero j velocity
  • concave negative velocity

25
Scientific Visualization II
  • Shape, color, opacity mapped to j vorticity

Shape, color, opacity mapped to j vorticity
26
Information Visualization
  • X Gold
  • Y US
  • Z Federal Reserve
  • Shape Stock Prices
  • Color Noriega

27
Implicit Shape Visualization (Rohrer, Ebert,
Sibert)
  • Implicit Surface Modeling (ISM)
  • Blobby models, metaballs, soft objects
  • Arbitrarily shaped functions
  • Automatic blending, CSG
  • Procedurally-generated
  • Global Density Field (F)
  • Produced from sum of potential field source
    functions

F(p) ? fi dist(p)
28
Implicit Shape Visualization Techniques
  • 1. Document Content
  • Shape (blobby text)
  • 2. Corpus Relationships
  • Proximity clustering
  • 3. Combine
  • Content (shape)
  • Relationships (cluster shells)
  • Focuscontext

29
Document Visualization Blobby Text
  • Map n Dimensions to Equally-spaced Spherical
    Directions in 3-space
  • n directions emanating from origin of sphere
  • Magnitude of directional vectors proportional to
    corresponding data value
  • Point source field function at end of vectors

30
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31
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32
New Examples
33
Transparency Textured Implicits
34
Corpus Visualization
  • Compute Document Similarities
  • Relationship graph
  • 3D Proximity Clustering
  • Mass-spring simulation
  • Visualization
  • Fit implicit surface model to cluster space

35
Combined Visualization
  • 3D Proximity Clustering
  • Semi-transparent cluster shells
  • Individual Documents
  • Content-based shape
  • FocusContext
  • Examples

InfoViz and Shakespeares Richard II and Richard
III
36
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37
Recent Work with SFA
  • New Features
  • Multi-vector / glyph display added (3 data
    dimensions mapped to each vector direction)
  • Multiple dataset display added
  • Data filtering for each data dimension
  • Communication with Fanatic Telltale
  • Communication with Jackal agent completed
  • Standard 2HI techniques now overloaded on mouse
    interface (subsetting, scale, rotation, zoom)
  • Only 2HI feature not available in mouse
    interface is the Slice View
  • Substantial documentation
  • Interactive lens visualization
  • Multi-threaded interaction

38
Interactive Lens Visualization Techniques
  • Three Types
  • Contour plate
  • Texture-based volume rendering
  • X-ray projection (thin slab)
  • Allows Display of More Data Variables /
    Dimensions
  • To Appear at IEEE Visualization 99

39
Contour Plate of Wall Street Journal
40
X-Ray Plate of WSJ Data
41
SFA Initial Perceptual Studies
  • Perceptual Study Experiment Completed this Summer
  • Initial Results
  • 10 steps in transparency
  • 21 in superquadric shape
  • Preattentive test -- Wheres Waldo?
  • Experiment Completed, analysis under way

42
Multi-Threaded Interaction Software
Architectures
  • The usual drawing process is
  • Draw on BackRGB while FrontRGB refreshes CRT
  • Clear BackRGB frame buffer and Z-buffer
  • Draw all objects in BackRGBZ
  • Swap Back and Front RGB buffers
  • Front buffer is used to refresh CRT
  • All graphical objects updated simultaneously
  • Many polygons to draw implies a slow update rate

43
Drawing with 3D Trackers
  • Usual Process
  • Get 3D Tracker position orientation
  • Process button hits and interaction with 3D scene
  • Draw 3D scene
  • Draw 3D cursors
  • Swap Buffers
  • MR Toolkit
  • Written by Shaw Green at U of Alberta
  • Licensed by 600 academic research sites
    worldwide

44
3D Interaction
  • For True Interaction, Need
  • gt10 updates/second
  • Lags lt 100ms
  • Lag -- Still the Most Significant Problem
  • Lags gt 50ms are noticeable
  • Lags gt100ms start to affect performance
  • Lags gt500ms destroy interaction
  • Users adopt move-and-wait strategy

45
Fast Update
  • How to Get Update Rates gt 10 Updates/sec?
  • Buy a fast graphics computer
  • Separate application from graphics
  • SGI Performer uses a 3-stage pipeline
  • MR Toolkit Computation process
  • Decoupled simulation
  • Draw less stuff
  • Decimate polygonal model
  • Draw cheap approximations
  • Textures approximate object, perhaps

46
Lag
  • Lag Is the Time From User Input to Graphics
    Response
  • Sum of Lags in System
  • Tracker lag
  • Data transmission lag
  • Drawing lag
  • How to Get Low Lags?
  • Predictive filters
  • Tuning tracker data timing
  • Fast update rate

47
Multi-Threaded Drawing
  • Another Solution Class
  • Draw in multiple frame buffer segments
    simultaneously
  • Draw 3D Cursors on Overlay Planes
  • Perform 3D interaction in real time
  • Draw Full 3D Scene in RGB Z Planes
  • Allow different update rates on the screen
  • Same advantage as mouse cursor menus on a 2D
    frame buffer

48
Video
  • Video Shows
  • SFA with multi-threaded 3D trackers

49
Multi-Thread Advantages
  • Allows Real-time Update of 3D Tracker Cursors
  • Overlay update can do menu interaction
  • Interaction with syntactic elements
  • RGB update can take as long as it likes
  • Limited semantic update is possible
  • picking on the front-buffer data set
  • Both RGB and Overlay threads are separate from
    any Computation process or thread

50
Plans
  • Create More Java-based Tools (e.g., Alpha,
    Colormap Editors)
  • Continue to Develop Version That Communicates
    With Current Agency Tools
  • Finish Time-sequence Support
  • Experiment with Performance of Java-based Glyph
    Visualization
  • Add Isosurface Rendering for Cluster and Metadata
    Display
  • Explore Metadata Visualization Techniques and
    Visualization of LSI Results
  • Extend Perceptual Studies to User Studies of SFA

51
Conclusion
  • Glyph Rendering Allows
  • Comprehensible display of multiple variables
  • Spatialization of complex relationships
  • Minimally-immersive Visualization Aids
  • 3D perception and feature detection
  • Procedural Shape Generation
  • Useful for encoding multiple data dimensions
    (1-14)
  • Allows visual exploration of information spaces
  • More Effective Use of the Human Perceptual System
    is Essential for Visualization

52
Acknowledgments - Collaborators
  • UMBC / Baltimore / D.C.
  • Randy Rohrer (DoD)
  • Aaron Roberts (NASA)
  • Jim Kukla, Pradyut Panda, Ted Bedwell, Amen Zwa
  • Chris Morris, Alex Eller, Joe Romano, Ian
    Soboroff
  • Funding DoD, NASA, NSF, NSERC
  • U. Regina / U. Washington
  • James Hall, Dee Jay Randall, Brook Bakay,
    Christine Blahut, Ben Korvemaker, Aaron Jones

53
MR Toolkit Structure
  • Distributed Processes

Tracker Servers
Computation
3D Model
Inter-Process Communication
Shared memory
Master Process
Display
54
Many Update Loops
  • The overlay scheme introduces 2 loops

Tracker Servers
Computation
3D Model
Tracker Thread
Shared memory
Shared memory
OverlayThread
RGB Thread
Display
55
Many Update Loops
  • Overlays may access 3D Model

Tracker Servers
Computation
3D Model
Tracker Thread
Shared memory
Shared memory
OverlayThread
RGB Thread
Display
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