Effects of Global Illumination Approximations on Material - - PowerPoint PPT Presentation

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Effects of Global Illumination Approximations on Material - - PowerPoint PPT Presentation

Jan 18, 2023 178 likes •669 views

Effects of Global Illumination Approximations on Material Appearance Jaroslav James Kavita Kivnek Ferwerda Bala Cornell University & Rochester Institute of Cornell University Charles University, Prague Technology Global

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Jaroslav Křivánek James Ferwerda Kavita Bala

Effects of Global Illumination Approximations on Material Appearance

Cornell University & Charles University, Prague Rochester Institute of Technology Cornell University

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  • Required for accurate appearance, but slow

2

Global illumination rendering

scene: Autodesk | rendering: Edgar Velázquez-Armendáriz

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  • Fast GI algorithms are inaccurate

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Global illumination rendering

scene: Autodesk | rendering: Edgar Velázquez-Armendáriz

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  • VPL rendering (Instant Radiosity [Keller 1997])

– Fast & popular – Image artifacts & energy losses

  • Impact of VPL rendering on visual fidelity

– Systematic perceptual study

4

Overview

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  • Perceptually-based rendering

– Visible Difference Predictor

[Mitchell 87, Bolin and Meyer 95/98, Myszkowski 02, …]

– Illumination components

[Stokes et al. 04; Debattista et al 05]

– Higher-level processing

[Yee et al. 01, O’Sullivan et al. 04]

– Material appearance

[Pellacini et al. 00; Westlund and Meyer 01; Fleming et al. 03; Khan et al. 06; Vangorp et al. 07/08]

– Visual Equivalence [Ramanarayanan et al. 2007] …

5

Related work

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  • Visually equivalent =

– Same scene appearance – Visibly different

  • Foundation of our work

– Apply visual equivalence to VPL rendering

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Related work – Visual equivalence

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  • Based on Instant Radiosity [Keller 1997]
  • Approximate indirect illumination by
  • 1. Generate VPLs

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Related work – VPL rendering

  • 2. Render with VPLs
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  • 1. Interactive GI (≈ 1,000 VPLs)

[Wald et al. 02; Segovia et al. 07; Laine et al. 07; Ritschel et al. 08; Dong et al. 09; Yu et al. 09 ; …]

  • 2. Preview-quality (≈ 100,000 VPLs)

[Hašan et al. 07/09]

  • 3. High-quality ( > 1,000,000 VPLs)

[Walter et al. 05/06]

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Related work – VPL rendering

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VPL rendering is fast, but…

9

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  • Q: When do VPL methods produce high-fidelity

renderings?

  • A: Systematic perceptual study

– trade-offs : VPL parameters vs. visual fidelity

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VPLs for high-fidelity rendering

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– VPL count – clamping level

VPL Rendering Parameters

VPL count clamping level

VPL rendering parameters

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– VPL count – clamping level

VPL Rendering Parameters

VPL count clamping level

VPL rendering parameters

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Space of rendering parameters

clamping level VPL count

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  • How are the thresholds affected by

– shape complexity? – material? – illumination?

  • Outline

– Experiment design – Results & validation – Applications

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Psychophysical experiments

clamping level VPL count

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Test objects – Shape complexity

  • Same as [Ramanarayanan et al. 07]
  • G0 ... sphere
  • G1-G3 ... bumpy spherical objects
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Test objects – Materials

Ward-Dür BRDF:

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Test objects – Materials

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Ward-Dür BRDF:

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Test objects – Materials

Ward-Dür BRDF:

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Test objects – Materials

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Ward-Dür BRDF:

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  • Art gallery café
  • Studied object
  • n a pedestal

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Scene

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  • Different VPL rendering

parameters

– 3 VPL counts – 11 clamping levels

clamping level VPL count

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Stimulus images

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Stimulus images –VPL count

1,000 (1k) Interactive rendering 100,000 (100k) Preview-quality rendering 5,000,000 (5M) High-quality rendering

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  • 11 levels from none to severe

(C0 – C10)

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Stimulus images – Clamping level

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  • Standard two-alternative forced choice method
  • 480 trials, 12 participants

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Experiment 1: Artifact visibility

clamping level VPL count

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  • Standard two-alternative forced choice method
  • 520 trials, 14 participants

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Experiment 2: Material change

VPL count clamping level

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VPL count clamping level

  • Extract thresholds from subjects’ answers

– Standard 75% 2 AFC threshold criterion

Data analysis

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1k 100k 5M C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9

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Experiment results

1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9
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SLIDE 28 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9

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Trends – VPL count

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SLIDE 29 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9

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Trends – VPL count

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SLIDE 30 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9

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Trends – VPL count

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SLIDE 31 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9

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Trends – VPL count

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SLIDE 32 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9

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Trends – VPL count

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SLIDE 33 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9

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Trends – Material contrast gloss

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SLIDE 34 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9

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Trends – Shape complexity

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SLIDE 35 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M 1k 100k 5M C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9 C0 C2 C4 C6 C8 C10 C1 C3 C5 C7 C9

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Trends – Shape complexity

≡ ≡

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SLIDE 36

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Trends – Illumination

indirect-only direct-and-indirect

  • Does accurate direct illumination help preserve

material appearance?

– No significant improvement measured – Further investigation needed

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  • 1. Real-world

geometry

– Trends confirmed

  • 2. New material (diffuse)

– Most forgiving material – Need more than 1k VPL to achieve equivalence

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Validation

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  • Per-object clamping
  • Luminance normalization

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Applications

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  • Energy compensation [Kollig & Keller 04]

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Application – Per-object clamping

+ =

clamping (VPL) compensation (PT)

→

≡

+ =

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  • Visual equivalence in space of VPL parameters
  • Trends in equivalence

– VPL count – Shape complexity – Contrast gloss decrease

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Summary of results

clamping level VPL count VPL count

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  • Adequacy of VPL methods for high fidelity

rendering

  • Take-home messages

– VPL methods produce equivalent renderings for a wide range of scene settings – 1k VPLs used in interactive apps → no equivalence – Smooth metal & simple shape → no equivalence

  • Solid perceptual foundation for VPL methods

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Conclusions

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  • Model for visual equivalence in VPL rendering
  • Effects of accurate direct illumination

– Ambiguity between artifacts and highlights

  • Scalable & equivalent VPL methods

42

Future work

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  • Marie Curie Fellowship PIOF-GA-2008-221716
  • NSF CAREER 0644175
  • NSF CPA 0811680
  • Intel
  • Microsoft
  • Experiment participants

43

Acknowledgements

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Thank you

≡

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Additional Slides

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SLIDE 46

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Ambiguity: highlights vs. artifacts

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  • Re-introduce energy removed by clamping

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match avg. luminance

Apps: Luminance normalization

  • Validation

– Can increase equivalence

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SLIDE 48

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Apps: Luminance normalization

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SLIDE 49

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Trends – Material roughness