Frequency Analysis and Sheared Reconstruction for Rendering Motion Blur Kevin Egan Yu-Ting Tseng Nicolas Holzschuch Frédo Durand Ravi Ramamoorthi Columbia University Columbia University Grenoble University MIT CSAIL University of California, Berkeley
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Frequency Analysis and Sheared Reconstruction for Rendering Motion Blur Kevin Egan Yu-Ting Tseng Nicolas Holzschuch Frédo Durand Ravi Ramamoorthi Columbia.
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Frequency Analysis and Sheared Reconstruction for Rendering Motion Blur
Frequency Analysis and Sheared Reconstruction for Rendering Motion Blur
Kevin Egan
Yu-Ting Tseng
Nicolas Holzschuch
Frédo Durand
Ravi Ramamoorthi
Columbia University
Columbia University
Grenoble University
MIT CSAIL
University of California, Berkeley
OverviewOverview
Introduction
• Overview of Frequency Analysis
• Sampling and Sheared Filter
• Implementation
• Results
Motion BlurMotion Blur
• Objects move while camera shutter is open
– Image is “blurred” over time
• Expensive for special effects
• Necessary to remove “strobing” in animations
Garfield: A Tail of Two KittiesRhythm & Hues StudiosTwentieth Century-Fox Film Corporation
The IncrediblesPixar Animation StudiosWalt Disney Pictures
A Simple ApproachA Simple Approach
• For each pixel
– Sample many different moments in time
t = 1.00
t = 0.75
t = 0.50
t = 0.25
t = 0.00
t [0.0, 1.0]
A Simple ApproachA Simple Approach
• The simple approach is expensive
• Can we do better?
ObservationObservation
• Motion blur is expensive
• Motion blur removes spatial complexity
Standard MethodStandard Method
• Use axis-aligned pixel filter at each pixel
• Requires many samples
SPACE
TIM
E
space-time samples
axis-aligned filter
Our MethodOur Method
• Use a different filter shape at each pixel
• Filter sheared in space-time
• Fewer samples and faster renders
SPACE
TIM
E
space-time samples
sheared filter
Previous WorkPrevious Work
• Plenoptic Sampling
Chai et al., 2000
Sheared reconstruction filter in space-angle
• A Frequency Analysis of Light Transport
Durand et al., 2005
Analysis of transport, reflection and occlusion
• We extend both to space-time
Previous WorkPrevious Work
• Multidimensional Adaptive Sampling
Hachisuka et al., 2008
Anisotropic reconstruction based on contrast
Our method based on local freq estimates
• Spatial Anti-Aliasing for Animation Sequences with Spatio-Temporal Filtering