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Interactive Multi-Perspective Views of Virtual 3D Landscape and City Models

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Abstract

Presentation of Research Paper "Interactive Multi-Perspective Views of Virtual 3D Landscape and City Models"
Interactive Multi-Perspective Views
of Virtual 3D Landscape
and City Models
Haik Lorenz, Matthias Trapp, Markus Jobst, Jürgen Döllner
Hasso Plattner Institute
Computer Graphics Systems Group
Prof. Dr. Jürgen Döllner
University Potsdam
www.hpi.uni-potsdam.de/3d
www.3dgi.de
08.05.2008 Hasso Plattner Institute, University of Potsdam 2
Motivation: Why Multi-Perspective Views ?
WRAP UP: Goals for 3D Visualization
1. Maintain advantages of 3D visualization
2. Offer navigation and orientation aid
3. Increase the effectiveness of available screen space
4. Reduce noise and dead values in the distance
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Existing Solution: Detail + Overview Visualization
Detail Overview
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Our Solution: Multi-Perspective Views
Pedestrian View Deformation
Bird’s Eye View Deformation
Outline
Related Work
Concept
Implementation Sketch
Performance Results & Discussion
Future Work & Open Issues
Conclusions
08.05.2008 Hasso Plattner Institute, University of Potsdam 5
Related Work
Art of H.C. Berann
Panorama Maps
with Non-linear Ray-tracing
[Falk ’07]
Detail-In-Context Visualization for Satellite Imaginary
[Böttger, EG’08]
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Concept Effective Presentation of Spatial 3D Environments
One concept:
The Bendable Ground Plate
Two 3D visualization approaches:
Bird’s Eye View Deformation (Progressive Perspective)
Which direction am I looking to?”
Pedestrian View Deformation (Degressive Perspective)
Where am I going to?”
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Concept – Bird’s eye View Deformation – Parameterization
C
T
T’
bi
ri
b
Image
plane rβ
View-dependent parameters
Ccamera position
β viewing angle of the reference plane
biline separating focus and transition zone in the image
riline of the horizon in the image
ri
bi
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Concept – Pedestrian’s View Deformation – Parameterization
T
C
CT
β
T’
b
dbds
re
Image
plane
View-dependent parameters
Ccamera position
β angle between Tand T’
dbdistance between CT(Cprojected onto T) and b
ds width of the transition zone’s source area
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Concept – … In Terms of Focus + Context Visualization
CONTEXT
CONTEXT
FOCUS
FOCUS
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Concept Graphical Representations of Focus & Context Areas
Cartographic design of the visualization:
Distinct rendering styles for focus and context areas
Transition zone: blending between focus and context
Vertex-based interpolation (style interpolator)
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Implementation Sketch
Clue: Deformation before standard perspective projection
Global Deformation [Baar ’84]:
Per vertex, GPU based
Using vertex shader functionality
de Casteljau algorithm for Bézier spline:
Characteristics:
Single-pass rendering technique
Interactive, deformation recalculated per frame
No caching of deformed data necessary
Calculate Perpendicular Point
Calculate Transformation Matrix
Calculate Style Interpolator
Transform Vertex (Bend)
Standard Perspective Projection
Vertex Shader
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Performance Results & Discussion (1)
Test Data:
16,000 generically textured buildings, ~100 landmarks,
3 GB color aerial photo, 250 MB grayscale map,
Digital terrain model
Resolution Configuration Path FPS
with bend FPS
without bend FPS
costs
1600 x 1200 Pedestrian’s
view 111.72 12.95 1.23
219.33 15.69 -3.64
Bird’s eye
view 38.35 29.86 21.51
46.73 17.64 10.91
1024 x 768 Pedestrian’s
view 117.85 15.63 -2.22
222.75 17.69 -5.06
Bird’s eye
view 38.87 27.24 18.37
45.42 16.07 10.65
800 x 600 Pedestrian’s
view 120.54 16.49 -4.05
223.94 18.42 -5.52
Bird’s eye
view 38.74 27.26 18.52
48.48 19.52 11.04
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Performance Results & Discussion (2)
Performance Issues:
Main bottleneck = texture access
Cache efficiency is reduced dramatically
Additional data handling overhead for rendering 2 styles
Conclusion:
Using only adapted view frustum culling is not sufficient
Use hardware-based occlusion culling algorithms
Use distance-based geometric Level of Detail (LoD)
Configuration Path bytes/frame
with bending bytes/frame
without bending bytes/frame
cost
Pedestrian’s view 1 260,207 407,822 -147,615
2 122,729 215,398 -92,669
Bird’s eye view 3 5,720,803 190,824 5,529,979
4 2,555,602 243,067 2,312,535
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Future Work & Open Issues (1)
Improve User Interaction:
Transitions between bird’s eye and pedestrian view deformation
Adjust parameterization with respect to users speed or similar
Conduct user studies
Technical Enhancements:
Use dynamic mesh refinement for geometry [Lorenz, WSCG 08]
Add thematic information
Transfer Concept To:
Pedestrian View: Mobile Devices ?
Bird’s Eye View: Navigation Systems ?
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Future Work & Open Issues (2)
[Jobst, VISUAL 08, in review]
Focus on cartographic aspects:
Minimize transition zone
Incorporate levels of detail/abstraction
Use non-photorealistic rendering (NPR)
[Glander, ACMGIS 2007]
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Future Work & Open Issues (3)
Silhouette enhancement via geometric scaling
[Glander, LBS 2007]
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Conclusions
Features:
Interactive combination of two views
Seamlessly style interpolation
Increase effectiveness of representations
Extensible concept
Performance round-up:
Pedestrians View: minimal increase
Bird’s Eye View: heavy decrease
Possibilities for optimization
Future work:
Generalization of bendable plane concept
More styles for focus & context areas
Focus on: the user and more use cases
08.05.2008 Hasso Plattner Institute, University of Potsdam 18
Demo
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Contact
Thank You !
QUESTIONS ?
Matthias Trapp
matthias.trapp@hpi.uni-potsdam.de
Computer Graphics Systems Group
Prof. Dr. Jürgen Döllner
www.hpi.uni-potsdam.de/3d
Researchgroup 3D-Geoinformation
www.3dgi.de
08.05.2008 Hasso Plattner Institute, University of Potsdam 20
... Several prior multiperspective visualization efforts target specifically urban and terrain scenes and opt for the approach of deforming distant, occluded geometry upward, while pushing near, occluding geometry downward [31], [32], [33]. One system improves spatial awareness through disocclusion in large-scale scenes, by providing the user with a choice of a large number of video feeds acquired from multiple vantage points [31]. ...
... Benefiting from the stable ground geometry, our visualization supports an intuitive user interface where a ROI is directly selected by the user's gaze towards the ground plane, as opposed to manually inputting deformation parameters [31]. When multiple ROIs are identified, our visualization deploys multiple secondary views to disocclude individual ROIs with localized deformation of the geometry, whereas prior work deforms large terrain partitions without low-level granularity of the disocclusion effect [31], [32], [33]. ...
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