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Chapter 4:
Exploiting Temporal Coherence in Walkthrough Rendering
Abstract
In this chapter, we consider accelerated rendering
of walkthrough animation sequences
using a combination of ray tracing and Image-Based
Rendering (IBR) techniques. Our goal is to derive
as many pixels as possible using inexpensive IBR
techniques without affecting the animation quality.
A perception-based spatio-temporal
Animation Quality Metric (AQM) is used to automatically
guide such a hybrid rendering. The Image Flow (IF)
obtained as a by-product of the IBR computation
is an integral part of the AQM. The final animation
quality is enhanced by an efficient
spatio-temporal antialiasing, which utilizes
the PF to perform a motion-compensated filtering.
Animations
Scene: ATRIUM
As a first case study for our walkthrough animation we selected an Atrium of the University of Aizu. The considered animation path is shown below.
We marked the location of keyframes and an inbetween frame along the animation
path using the following color convention:
- green - the initial keyframes (interval = 25 frames)
- yellow - keyframes for animation segments that we split (interval = 12 or 13 frames)
- cyan - currently selected keyframes
- red - currently derived inbetween frame
IBR & Ray Tracing with motion-compensated filtering QuickTime movie (5MB)
- All keyframes fully ray traced
- Inbetween frames computed using a hybrid of IBR and ray tracing techniques
- Spatial antialiasing: performed
- Temporal antialiasing: performed
- Motion-compensation: performed
IBR & Ray Tracing without any filtering QuickTime movie (7MB)
- All keyframes fully ray traced
- Inbetween frames computed using a hybrid of IBR and ray tracing techniques
- Spatial antialiasing: not performed
- Temporal antialiasing: not performed
- Motion-compensation: not performed
IBR only animation with motion-compensated filtering QuickTime movie (5MB)
- All keyframes fully ray traced
- All inbetween frames computed using IBR techniques
- Spatial antialiasing: performed
- Temporal antialiasing: performed
- Motion-compensation: performed
Scene: ROOM
Ray Tracing with adaptive supersampling QuickTime movie (5MB)
- All frames fully ray traced with adaptive supersampling
- Spatial antialiasing: not performed
- Temporal antialiasing: not performed
- Motion-compensation: not performed
Ray Tracing with adaptive supersampling and perception-based antialiasing QuickTime movie (5MB)
- All frames fully ray traced with adaptive supersampling
- Spatial antialiasing: performed
- Temporal antialiasing: performed
- Motion-compensation: performed
Raw Ray Tracing with perception-based antialiasing QuickTime movie (5MB)
- All frames fully ray traced
- Spatial antialiasing: performed
- Temporal antialiasing: performed
- Motion-compensation: performed
IBR & Ray Tracing with perception-based antialiasing QuickTime movie (5MB)
- All keyframes fully ray traced
- Inbetween frames computed using a hybrid of IBR and ray tracing techniques
- Spatial antialiasing: performed
- Temporal antialiasing: performed
- Motion-compensation: performed