Annotating 3D Content in Interactive, Virtual Worlds

Christine LEHMANN Jürgen DÖLLNER

Agenda

1. Motivation

2. Image-based Labeing of 3D Content

3. Enhanced Visibility Analysis

4. Smooth Transitions

5. Conclusions

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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Foundations: What is Labeling?

Labeling algorithms are faced with a number of fundamental challenges including:

□ Find non-conflicting positions

close to labeled objects

in the view plane (label embedding)

□ Guarantee non-ambiguous assignments

□ Ensure readability of labels

Different Approaches for labeling

with different advantages :

□ Internal labels provide fast assocating

to labeled objects

□ External labels can be applied

to very small objects (small visible amount)

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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Example: Boundary Labeling (external)[Bekos et al.: „Boundary Labeling with OctilinearLeaders“, 2008]

Example: Street Labeling (internal)

Example: Google Maps

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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Example: Google Earth (1/3)

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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Example: Google Earth (2/3)

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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?

Example: Google Earth (3/3)

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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?

Contribution

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

8 ■ Our method enables attaching labels to

salient points and lines for internal label

placement

■ It uses visibility analysis to overcome

general labeling obstacles, most

important unambiguous label assignment

Use both internal and external labeling:

■ Apply internal and external labels

depending on visibility analysis

■ Enable transitions between external and

internal label placement

Example: Internal and External labels combined

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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Image-based Labling of 3D Content

■ Labels are placed exclusively on

visible areas of labeled objects

■ Visible pixels of 3D objects are

collected from the identity-map

(id-map)

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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Example: Internal Label Placement and External Label Placement with according id-maps.

Enhanced Visibility Analysisfor Labeling

■ From visible pixels, compute the distance transform and the normal field

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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Enhanced Visibility Analysisfor Labeling

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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Enhanced Visibility Analysisfor Labeling

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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Enhanced Visibility Analysisfor Labeling

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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Enhanced Visibility Analysisfor Labeling

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

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Smooth Transitions

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

16 Labels switch from internal (with horizontal orientation) to external by

”walking” along the arrows (normal field).

Conclusions

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

17Image-based label placement:

■ Suitable for responsive systems and

interactive 2D/2.5D/3D systems

■ Easy integration into service-based

systems

Enhanced Visibility-driven

label placement:

■ Unambiguous label assignments

■ No time-consuming 3D geometry

analysis of labeled objects

■ Dynamic switching between internal

and external labeling

■ Simultaneous usage of external and

internal labeling based on visibility

analysis

Conclusions

Annotating 3D Content in Interactive, Virtual Worlds | Web3D 2013 | Christine LEHMANN

18 Contact:

www.4dndvis.de

Christine Lehmann

christine.lehmann@hpi.uni-potsdam.de

Jürgen Döllner

juergen.doellner@hpi.uni-potsdam.de

Publications:

http://www.hpi.uni-potsdam.de/doellner/4dndvis/publikationen.html

This work was funded by the Federal Ministry of Education and Research (BMBF), Germany

within the InnoProfile Transfer research group "4DnD-Vis".