Multidimensional Adaptive Sampling and Reconstruction for Ray Tracing Toshiya Hachisuka * Wojciech Jarosz * Richard Peter Weistroffer † Kevin Dale ‡ Greg Humphreys † Matthias Zwicker * Henrik Wann Jensen * * University of California, San Diego † University of Virginia ‡ Harvard University
4 Sampling and Realistic Rendering • Distributed ray tracing [Cook et al. 84] Pixel Lens Objects Image Plane
8 Adaptive Sampling Image based adaptive sampling • Recursive subdivision [Whitted 80] • Stochastic adaptive sampling [Mitchell 87, 91] • Perceptually based criterion [Bolin and Meyer 98] • Divergence based criterion [Rigau et al. 03] • MISER [Press and Farrar 90] [Leeson 03]
9 Adaptive Sampling Image based adaptive sampling • Recursive subdivision [Whitted 80] • Stochastic adaptive sampling [Mitchell 87, 91] • Perceptually based criterion [Bolin and Meyer 98] • Divergence based criterion [Rigau et al. 03] • MISER [Press and Farrar 90] [Leeson 03]
10 Motion Blur
11 Motion Blur
12 Motion Blur
13 Motion Blur Time
13 Motion Blur Time Pixel
14 Motion Blur Time Pixel
14 Motion Blur Time Pixel
15 Motion Blur Time Pixel
16 Motion Blur Time Pixel
17 Adaptive Sampling [Mitchell 91] Time Pixel
18 Adaptive Sampling [Mitchell 91] Time Pixel
19 Adaptive Sampling [Mitchell 91] Time Pixel
20 Adaptive Sampling [Mitchell 91] Time Pixel
21 Adaptive Sampling [Mitchell 91] Time Pixel
22 Adaptive Sampling [Mitchell 91] Time Pixel
23 Adaptive Sampling [Mitchell 91] Time Pixel
24 Adaptive Sampling [Mitchell 91] Time Pixel
25 Adaptive Sampling [Mitchell 91] Time Pixel
26 Adaptive Sampling [Mitchell 91] Time Pixel
27 Adaptive Sampling [Mitchell 91] Time Pixel
28 Adaptive Sampling [Mitchell 91] Time Pixel
29 Adaptive Sampling [Mitchell 91] Time Pixel
30 Adaptive Sampling [Mitchell 91] Time Pixel
31 Adaptive Sampling [Mitchell 91] Time Pixel
32 Adaptive Sampling [Mitchell 91] Time Pixel
33 Adaptive Sampling [Mitchell 91] Time Pixel
34 Adaptive Sampling [Mitchell 91] Time Pixel
35 Adaptive Sampling [Mitchell 91] Time Pixel
36 Adaptive Sampling [Mitchell 91] Time Pixel Sampled Exact
37 Motion Blurred Sphere 1 Samples / Pixel 4 16 64 Reference
38 Motion Blurred Sphere 1 Samples / Pixel 4 16 64 Reference
39 Adaptive Sampling [Mitchell 91] Time Pixel Sampled Exact
40 Key Idea of Our Work • Conventional adaptive sampling • Only adaptive on pixel axis • Multidimensional adaptive sampling • Adaptive on all axes
41 Multidimensional Adaptive Sampling Time Pixel
42 Multidimensional Adaptive Sampling Time Pixel
43 Multidimensional Adaptive Sampling Time Pixel
44 Multidimensional Adaptive Sampling Time Pixel
45 Multidimensional Adaptive Sampling Time Pixel
46 Multidimensional Adaptive Sampling Time Pixel
47 Multidimensional Adaptive Sampling Time Pixel
48 Multidimensional Adaptive Sampling Time Pixel
49 Multidimensional Adaptive Sampling Time Pixel
50 Multidimensional Adaptive Sampling Time Pixel
51 Multidimensional Adaptive Sampling Time Pixel
52 Multidimensional Adaptive Sampling Time Pixel
53 Multidimensional Adaptive Sampling Time Pixel
54 Multidimensional Adaptive Sampling Time Pixel
55 Multidimensional Adaptive Sampling Time Pixel
56 Multidimensional Adaptive Sampling Time Pixel
57 Multidimensional Adaptive Sampling Time Pixel
58 Multidimensional Adaptive Sampling Time Pixel
59 Multidimensional Adaptive Sampling Time Pixel
60 Multidimensional Adaptive Sampling Time Pixel
61 Multidimensional Adaptive Sampling Time Pixel
62 Multidimensional Adaptive Sampling Time Pixel Sampled Exact
63 Motion Blurred Sphere - Comparison [Mitchell 91] Our method 1 4 16 64 Reference
64 Motion Blurred Sphere - Comparison [Mitchell 91] Our method 1 4 16 64 Reference
65 Motion Blurred Sphere Our Method 20 Low Discrepancy 15 Mitchell 10 5 0 1 4 16 64 256
66 Rendering is Integration • Each pixel value, L(x, y), is defined as multidimensional integration � � L ( x, y ) = f ( x, y, u 1 , . . . , u n ) d u 1 . . . d u n · · ·
67 Rendering is Integration • Motion blur is 1D integration over time (t) � L ( x, y ) = f ( x, y, t ) d t
68 Rendering is Integration • DOF is 2D integration over lens (u, v) �� L ( x, y ) = f ( x, y, u, v ) d u d v
69 Analytical Solution Time t Pixel L ( x ) x � L ( x ) = f ( x, t )d t
70 Analytical Solution Time t Pixel L ( x ) x � L ( x ) ≈ w i f ( x, t i ) i
71 Conventional Adaptive Sampling Time t Pixel L ( x ) x � L ( x ) ≈ w i f ( x, t i ) i
72 Multidimensional Adaptive Sampling Time t Pixel L ( x ) x � L ( x ) ≈ w i f ( x, t i ) i
73 Key Features • Exploits coherency beyond the image plane • Adaptive sampling based on deterministic samples • Theory applies to various effects
Results
75 Motion Blur (3D) - Reference 512 samples 27,488 sec
76 Motion Blur (3D) - Our Method 8 samples 672.2 sec
77 Motion Blur (3D) - [Mitchell 91] 12.67 samples 676.4 sec
78 Motion Blur (3D) - Comparison Our method [Mitchell 91] 8 samples / pixel 12.67 samples / pixel 672.2 sec 676.4 sec RMS: 0.0034 RMS: 0.0099
79 Depth of Field (4D) - Reference 512 samples 11,960 sec
80 Depth of Field (4D) - Our Method 16 samples 993 sec
81 Depth of Field (4D) - [Mitchell 91] 38.25 samples 980 sec
82 Depth of Field (4D) - Comparison Our method [Mitchell 91] 16 samples / pixel 38.25 samples / pixel 993 sec 980 sec RMS: 0.132 RMS: 0.192
Sampling Density 83
84 Area Light Source (4D) Our method Mitchell Our Method Mitchell Scene Setup 1 8 Area Light Source Samples / Pixel Occluders 64 64
85 Area Light Source (4D) Our method Mitchell Metropolis Our Method Mitchell Low Discrepancy Metropolis 1 8 Samples / Pixel 64 64
86 Area Light Source (4D) Our method Mitchell Metropolis Samples / Pixel 64 Area Light Source Occluders
87 Motion Blur + DOF (5D)
88 Future Work • More higher dimensional adaptive sampling • New adaptive sampling criterion • Application to more complex light transport
89 Conclusion • Produces images with less noise by fewer samples • Adaptive sampling in multidimensional space • Reconstruction from multidimensional samples • Applicable to various rendering effects
90 Acknowledgement • NSF CPA 0701992 • UCSD FW Grid Project • NSF Research Infrastructure Grant EIA-0303622 • All UCSD graphics lab members
91 Thanks
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