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LIGHT TRANSPORT 25/11/2011 Shinji Ogaki
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4 Papers Progressive Photon Beams Lightslice: Matrix Slice Sampling for Many- Lights Problem Modular Radiance Transfer Practical Filtering for Efficient Ray-Traced Directional Occlusion
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PROGRESSIVE PHOTON BEAMS Wojciech Jarosz et at.
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1.Cast Photons 2.Gather Photon Mapping Photon Query Point Fixed Search Radius
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LS+DS+E Paths Accurate Caustics Unlimited # of Photons Progressive Photon Mapping Photon Reverse Photon Search Radius
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Extension to Volume (LS+MS+E Paths) PPB (Progressive Photon Beam) Photon Beam Query Ray
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L: Radiance Tr: Transmittance s: Surface m: Media σs: Scattering Coefficient f: Phase Function Radiative Transport Equation Photon Beam Query Ray Xs S Xw W
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Beam x Beam 1D Estimator FluxKernel Scattering Coef
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Results
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LIGHTSLICE: MATRIX SLICE SAMPLING FOR MANY-LIGHTS PROBLEM Jiawei Ou et al.
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Many-Lights Problem Global Illumination (Diffuse Indirect Illum.) Matrix Interpretation of Many-Lights VPL (Virtual Point Light)
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Many-Lights Problem Global Illumination (Diffuse Indirect Illum.) Matrix Interpretation of Many-Lights VPL (Virtual Point Light)
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Many-Lights Problem Global Illumination (Diffuse Indirect Illum.) Matrix Interpretation of Many-Lights VPL (Virtual Point Light)
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Many-Lights Problem Global Illumination (Diffuse Indirect Illum.) Matrix Interpretation of Many-Lights VPL (Virtual Point Light)
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Many-Lights Problem Global Illumination (Diffuse Indirect Illum.) Matrix Interpretation of Many-Lights VPL (Virtual Point Light)
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Many-Lights Problem Global Illumination (Diffuse Indirect Illum.) Matrix Interpretation of Many-Lights VPL (Virtual Point Light)Sample
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Transport Matrix Close to Low Rank..
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Algorithm 1.Matrix Slicing 2.Slice Sampling 3.Initial Light Clustering 4.Per Cluster Refinement
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Results SliceVisualization
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Results (cont’d) Lightslice MRCS Lightcut
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Limitations Parameter Selection (# of Slices etc.) Glossy Surface Animation Matrix Sparsity Comprehensive Comparison is missing (Coherent Light Cut and Pixelcuts?)
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MODULAR RADIANCE TRANSFER Bradford J. Loos et al.
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Module Patched Local is Global Module
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Shapes
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Transport Matrix (Local) F: Direct to Indirect Transfer (One Bounce) Sample
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Reduced Direct-to-Indirect Transfer in Shape Truncated SVD of F Not so Sparse, Unfortunately Sample
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Reduced Direct-to-Indirect Transfer in Shape (cont’d) Light Prior (Basis for Plausible Direct Lighting) Id1Id2Idm……
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Reduced Direct-to-Indirect Transfer in Shape (cont’d) Truncated SVD of M Very Sparse Sample
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Reduced Direct-to-Indirect Transfer between Shapes (Local to Global) Interface
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Results
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Limitations Lighting Condition outside of the Light Prior High Frequency Glossy Transport Large Scale Indirect Shadows within Blocks Dictionary Shapes (e.g. Internal Occluders) User Interface
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PRACTICAL FILTERING FOR EFFICIENT RAY-TRACED DIRECTIONAL OCCLUSION Kevin Egan et al.
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Ambient Occlusion 1 1 1 0 0 (1+0+1+0+1)/5=0.6 Hemisphere
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1.Cast Rays 2.Filter Ambient Occlusion with a Sparse Set of Rays Expensive Cheap
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Distant Lighting in Linear Sub-Domains
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Frequency Analysis and Sheared Filtering Light(y) Receiver(x) x y Occluder Spectrum Bandlimited by Filter Flatland Scene Occlusion Function f(x, y) 0 Receiver(x) 1 0 Light(y) 1 x y Occluders x y
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Frequency Analysis and Sheared Filtering (cont’d)
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Rotationally-Invariant Filter Infinitesimal Sub-domains
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Results 6+ mins to filter
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Limitations Artifacts due to Undersampling in the 1st Pass Smoothes out some Areas of Detail Noise in Areas where Brute Force Computation is used
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