Title: Inverse Rendering Methods for Hardware-Accelerated Display of Parameterized Image Spaces
1Inverse Rendering Methods forHardware-Accelerated
Display of Parameterized Image Spaces
Ziyad S. Hakura
2Real-time rendering of Parameterized Image
Spaces with Photorealistic Image Quality
Object Motion
Viewpoint Position
3- Animation time parameter
- Viewpoint parameter along circle
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6Cockpit Lighting
Day light
Night sky
7Interactive Toy Story
- Limited viewpoint motion
- Head motion parallax puts the user in the scene
- Character parameters e.g. happiness/sadness
- Rose98, Gleicher98, Popovic99
8Parameterized Image Spaces
- Space can be 1D, 2D or more
- Content author specifies parameters
Light motion
Object motion
Viewpoint position
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10Interactive Motion
View
Light
An interactive user is free to move anywhere in
the parameter space
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12Ray-Tracing
Texture-Mapping Graphics Hardware
13Ray Tracing
Display
Eye
14Z-Buffer Graphics Hardware
15Pixel Fill Rate vs. Time
16Overall Model
17Overall Model
18Overall Model
19Related Work
- Hardware Shading Models
- Diefenbach96, Walter97, Ofek98, Udeshi99,
Cabral99, - Kautz99, Heidrich99
- Image-Based Rendering (IBR)
- Chen93, Levoy96, Gortler96, Debevec96, Shade98,
- Miller98, Debevec98, Bastos99, Heidrich99, Wood00
- Animation Compression
- Guenter93, Levoy95, Agrawal95, Cohen-Or99
20Contributions
- Inverse rendering method for inferring texture
maps - Hardware-accelerated decoding of compressed
- parameterized image spaces
- Parameterized environment maps representation
- for moving away from pre-rendered samples
- Hybrid rendering for refractive objects
21Outline
- Motivation
- Texture Inference
- Parameterized Texture Compression
- Parameterized Environment Maps
- Hybrid Rendering
- Conclusion
22Consider a Single Image
p2
p1
Parameterized Image Space
Single Image
How do we represent the shading on each object?
23Texture Mapping
3D Mesh
24Texture Inference by Inverse Rendering
3D Mesh
2D Texture
25Linear Hardware Model
A x b
Unknown Texture Pixels
Ray-Traced Image
HW Filter Coefficients
26Texture Inference
x texture values
b ray-traced image
Ax b r(x)2
27Forward Mapping Method
28Ray-Traced
Inverse Fitted PSNR41.8dB
Forward Mapped PSNR35.4dB
29Outline
- Motivation
- Texture Inference
- Parameterized Texture Compression
- Parameterized Environment Maps
- Hybrid Rendering
- Conclusion
30Parameterized Texture Compression
Light
View
31Why compress textures instead of images?
- Textures better capture coherence
- Independent of where in image object appears
- Object silhouettes correctly rendered from
geometry - Viewpoint can move away from original samples
- No geometric disocclusions
32Laplacian Pyramid
33Adaptive Pyramid
34MPEG-Image, 3551 PSNR36.8dB
Laplacian-Texture, 3791 PSNR38.7dB
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36Runtime System
- Decompresses texture images
- Caches uncompressed textures in memory
- Textures in top of pyramid likely to be re-used
- Generates rendering calls to graphics system
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39Outline
- Motivation
- Texture Inference
- Parameterized Texture Compression
- Parameterized Environment Maps
- Hybrid Rendering
- Conclusion
40How to handle reflective objects?
Problem Movement away from pre-rendered views
gives a pasted-on look Solution Parameterized
Environment Maps
41Static Environment Maps (EMs)
- Generated using standard techniques
- Photograph a physical sphere in an environment
- Render six faces of a cube from object center
42Problem with Static EM
Ray-Traced
Static EM
Self-reflections are missing
43ParameterizedEnvironment Maps (PEM)
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45Environment Map Geometry
46Why Parameterize Environment Maps?
- Captures view-dependent shading in environment
- Accounts for geometric error due to approximation
- of environment with simple geometry
47 Surface Light Fields Miller98,Wood00
Surface Light Field
PEM
Dense sampling over surface points
of low-resolution lumispheres
Sparse sampling over viewpoints of
high-resolution EMs
48Layering of Paramaterized Environment Maps
- Segment environment into local and distant maps
- Allows different EM geometries in each layer
- Supports parallax between layers
49Segmented, Ray-Traced Images
Fresnel
EMs are inferred for each layer separately
50Inferred EMs per Viewpoint
Distant
Local Color
Local Alpha
51Experimental Setup
- 1D view space
- 1 separation between views
- 100 sampled viewpoints
52Ray-Traced vs. PEM
Closely match local reflections like
self-reflections
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54Movement Away from Viewpoint Samples
Ray-Traced
PEM
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56Layered PEM vs. Infinite Sphere PEM
Layered PEM
Infinite Sphere PEM
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59Outline
- Motivation
- Texture Inference
- Parameterized Texture Compression
- Parameterized Environment Maps
- Hybrid Rendering
- Conclusion
60How to handle refractive objects?
Problem Outgoing ray direction hard to predict
from first surface intersection
N
Refractive Path
Eye
Outgoing ray
Solution Hybrid Rendering
61Hybrid Rendering
62Hybrid Rendering
- Greedy Ray Path Shading Model
- Adaptive Tessellation
- Layered, Parameterized Environment Maps
63Greedy Ray Path Shading Model
Reflective Path
Refractive Object
N
Refractive Path
Eye
Trace two ray paths until rays exit refractive
object
64Comparison of Shading Models
Two-term greedy ray path
Full ray tree
65Adaptive Tessellation
- Two criteria
- Ray path topology
- Outgoing ray distance
- Consider both terms of shading model
66Layered EMs
67Inferred EMs
L1
L2
L3
Reflection Term
Refraction Term
Inferred Environment Maps
68Ray-Traced vs. Hybrid
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70Benefit of Hybrid Renderingover Ray-Tracing
- Lower cost
- Adaptive ray-tracing algorithm
- Lower cost and higher predictability
- Greedy two-term shading model
- Substitute environment with layered shells
71Outline
- Motivation
- Texture Inference
- Parameterized Texture Compression
- Parameterized Environment Maps
- Hybrid Rendering
- Conclusion
72Conclusion
- Provide photorealistic rendering of parameterized
- image spaces
- Texture inference by Inverse Rendering
- Parameterized Texture Compression
- Parameterized Environment Maps
- Hybrid Rendering
73Recommendations for Graphics Hardware
- Decompression of textures in hardware
- Compression algorithms
- Decoding from parameter-dependent texture blocks
- More dynamic range in texture pixels
- Ray-tracing for local models
74Future Work
- More sophisticated models for hardware rendering
- e.g. fitting area light sources
- Effect of hybrid rendering on compression
- More efficient pre-rendering of ray-traced images
- Multi-dimensional Ray-Tracing
- Higher dimensions
75Acknowledgements
76Acknowledgements
- Bernard Widrow
- John Snyder
77Acknowledgements
- Bernard Widrow
- John Snyder
- Anoop Gupta
78Acknowledgements
- Bernard Widrow
- John Snyder
- Anoop Gupta
- Pat Hanrahan
79Acknowledgements
- Bernard Widrow
- John Snyder
- Anoop Gupta
- Pat Hanrahan
- Jed Lengyel, Turner Whitted, and others at
Microsoft Research
80Acknowledgements
- Bernard Widrow
- John Snyder
- Anoop Gupta
- Pat Hanrahan
- Jed Lengyel, Turner Whitted, and others at
Microsoft Research - Graphics Friends at Stanford
81Acknowledgements
- Bernard Widrow
- John Snyder
- Anoop Gupta
- Pat Hanrahan
- Jed Lengyel, Turner Whitted, and others at
Microsoft Research - Graphics Friends at Stanford
- Administrators
- John Gerth, Charles Orgish, Kevin Colton
- Darlene Hadding, Ada Glucksman, Heather Gentner
82Acknowledgements
- Bernard Widrow
- John Snyder
- Anoop Gupta
- Pat Hanrahan
- Jed Lengyel, Turner Whitted, and others at
Microsoft Research - Graphics Friends at Stanford
- Administrators
- John Gerth, Charles Orgish, Kevin Colton
- Darlene Hadding, Ada Glucksman, Heather Gentner
- Friends
- Ulrich Stern, Ravi Soundararajan, Kanna Shimizu,
- Gaurishankar Govindaraju, Luke Chang, Johannes
Helander
83Acknowledgements
- Bernard Widrow
- John Snyder
- Anoop Gupta
- Pat Hanrahan
- Jed Lengyel, Turner Whitted, and others at
Microsoft Research - Graphics Friends at Stanford
- Administrators
- John Gerth, Charles Orgish, Kevin Colton
- Darlene Hadding, Ada Glucksman, Heather Gentner
- Friends
- Ulrich Stern, Ravi Soundararajan, Kanna Shimizu,
- Gaurishankar Govindaraju, Luke Chang, Johannes
Helander - Mother and Sisters Dima and Dalia
84Acknowledgements
- Bernard Widrow
- John Snyder
- Anoop Gupta
- Pat Hanrahan
- Jed Lengyel, Turner Whitted, and others at
Microsoft Research - Graphics Friends at Stanford
- Administrators
- John Gerth, Charles Orgish, Kevin Colton
- Darlene Hadding, Ada Glucksman, Heather Gentner
- Friends
- Ulrich Stern, Ravi Soundararajan, Kanna Shimizu,
- Gaurishankar Govindaraju, Luke Chang, Johannes
Helander - Mother and Sisters Dima and Dalia
- Father
85END