Visual%20Chatter%20in%20the%20Real%20World

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Visual Chatter in the Real World

• Shree K. Nayar

Computer Science Columbia University
With Guru Krishnan, Michael Grossberg, Ramesh
Raskar Eurographics Rendering Symposium June
2006, Nicosia, Cyprus Support ONR
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Direct and Global Illumination
surface
source
P
camera
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Related Work
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Fast Separation of Direct and Global Images

• Create Novel Images of the Scene

• Enhance Brightness Based Vision Methods

• New Insights into Material Properties

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Compute Direct and Global Images of a Scene
from Two Captured Images
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Direct and Global Components Interreflections
surface
source
i
camera
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High Frequency Illumination Pattern
surface
source
camera
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High Frequency Illumination Pattern
surface
source
camera
fraction of activated source elements
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Separation from Two Images
direct
global
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Minimum Illumination Frequency
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Other Global Effects Subsurface Scattering
translucent surface
source
camera
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Other Global Effects Volumetric Scattering
participating medium
surface
source
camera
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(No Transcript)
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(No Transcript)
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Verification
F
G
C
A
D
B
E
A Diffuse Interreflection (Board) B Specular
Interreflection (Nut) C Subsurface Scattering
(Marble) D Subsurface Scattering (Wax) E
Translucency (Frosted Glass) F Volumetric
Scattering (Dilute Milk) G Shadow (Fruit on
Board)
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Verification Results
A
B
1
G
E
0.8
F
0.6
0.4
D
marble
0.2
C
p
0
5
3
7
9
11
15
19
23
27
31
35
39
43
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Checker Size
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V-Grooves Diffuse Interreflections
concave
convex
Psychophysics Gilchrist 79, Bloj et al. 04
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Mirror Ball Failure Case
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Real World Examples Can You Guess the Images?
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Eggs Diffuse Interreflections
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Wooden Blocks Specular Interreflections
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Novel Images
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Photometric Stereo The Pseudo Shape
Actual Shape
Nayar et al., 1991
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Photometric Stereo using Direct Images
Bowl
Shape
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Variants of Separation Method
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Building Corner
3D from Shadows Bouguet and Perona 99
Stick
Shadow
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Building Corner
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Shower Curtain Diffuser
Shadow
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Shower Curtain Diffuser
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Kitchen Sink Volumetric Scattering
Volumetric Scattering Chandrasekar 50, Ishimaru
78
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Novel Image
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Peppers Subsurface Scattering
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Novel Images
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Real or Fake ?
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Tea Rose Leaf
Leaf Anatomy Purves et al. 03
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Translucent Rubber Balls
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Marble When BSSRDF becomes BRDF
Scene
Global
Direct
Subsurface Measurements Jensen et al. 01,
Goesele et al. 04
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Hand
Skin Hanrahan and Krueger 93, Uchida 96, Haro
01, Jensen et al. 01, Igarashi et al. 05, Weyrich
et al. 05
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Hands
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Separation from a Single Image
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Face
Direct
Global
Sum
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Skin Tone Control
Skin Color and Lipids Tsumura et al. 03
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Blonde Hair
Hair Scattering Stamm et al. 77, Bustard and
Smith 91, Lu et al. 00 Marschner et al. 03
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Hair Bidirectional Texture Function
Hair
Direct
Global
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Pebbles 3D Texture
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Pebbles Bidirectional Texture Function
Pebbles
Direct
Global
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Pink Carnation
Spectral Bleeding Funt et al. 91
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(No Transcript)
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Summary

• Fast and Simple Separation Method

• No Prior Knowledge of Material Properties

• Wide Variety of Global Effects

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