Spectral Texturing for RealTime Applications

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Spectral Texturing for Real-Time Applications
Presentation by Daniel Berger
Max Planck Institute for Biological
Cybernetics Tübingen, Germany
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Spectral Texturing
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Spectral Texturing
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Outline of the Talk

• Motivation
• Common limitations of textures
• How to overcome the limitations by using
  multi-layer texturing
• "Spectral Texturing" using textured transparency
  channels
• Spectral Texturing Limitations
• Outlook

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Motivation

• Psychophysical experiment on flight illusions
• acceleration over textured ground plane

• Texture should have detailed structure
  when viewed very close and far away

• Texture should not produce artifacts

• Rendering in real-time on a common PC,
  using standard OpenGL

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Texture Mapping Limitations
Textures have a limited resolution and size.
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Texture Mapping Limitations - Aliasing
Textures generate aliasing if they contain
higher spatial frequencies than the screen
resolution
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Texture Mapping Limitations - Remedies
Blockyness
Bilinear interpolation
Blurred Texture
Aliasing
Mip-mapping
Texture disappears far away
Pattern Repetitions
"Splatting", "Bombing" etc.
Many textured patches have to be rendered
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Texture Mapping Limitations Mip-Mapping and
Interpolation
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A spectral view on textures
Screen size
Screen resolution
Features smaller than texture resolution
Textures spectral coverage
Features larger than texture size
Blockyness
Repetitions
Spatial Frequency
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A spectral view on textures
Screen size
Screen resolution
Aliasing
Textures spectral coverage
Blockyness
Repetitions
Spatial Frequency
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A spectral view on textures Multi-Scale,
Multi-Level Texturing
Screen resolution
Screen size
Covering of blur by fine details
Mip-Mapping against aliasing
Aliasing
blurryness
Spatial Frequency
repeating structures
Covering of repeating tiles by large structures
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Multi-Scale Texturing
Mip-Mapping
Pattern Repetitions
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Multi-Scale Texturing
In each layer

• Mip-Mapping prevents aliasing

• Interpolation prevents blockyness

Between layers

• Larger-scaled layers cover repetitiveness of
  smaller-scaled layers

• Smaller-scaled layers provide fine detail
  ("Detail Texturing")

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Textured Transparency Maps
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Textured Transparency Maps"Spectral Texturing"
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Spectral Texturing is Realtime
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Spectral Texturing
Color Map
Transparency Map
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Spectral Texturing
Transparency map of each layer determines amount
of higher frequencies visible
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Spectral Texturing
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Back to the Motivation
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• Texture generated for the experiment

• Texture has detailed structure when viewed
  close and far away

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• Texture does not produce artifacts when
  scaled

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• Rendering in realtime on a common PC is
  possible, using standard OpenGL

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Limitations of Spectral Textures

• control over phase only within frequency bands
• ? hard edges difficult to model
• textures with structurally different subtextures
  difficult to model
• similar restrictions on arbitrary surfaces
• as other flat textures

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Extensions - Outlook

• Use different textures for the layers

• More complex textures by using several
  transparency maps (pixel shaders) tree-like
  texture construction

• Automatic generation of spectral textures
• from example photographs

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Spectral Texturing Examples
http//www.kyb.tuebingen.mpg.de/berger/spectralte
xturing/