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Creating Adaptive Views for Group Creating Adaptive Views for Group Video Teleconferencing Video Teleconferencing
– An Image-Based Approach – An Image-Based Approach
Ruigang YangRuigang Yang Celso Kurashima Celso Kurashima Andrew Nashel Andrew Nashel Herman Towles Herman Towles Anselmo Lastra Anselmo Lastra Henry FuchsHenry Fuchs
Ruigang YangRuigang Yang Celso Kurashima Celso Kurashima Andrew Nashel Andrew Nashel Herman Towles Herman Towles Anselmo Lastra Anselmo Lastra Henry FuchsHenry Fuchs
University of North Carolina University of North Carolina
at Chapel Hillat Chapel Hill
University of North Carolina University of North Carolina
at Chapel Hillat Chapel Hill
International Workshop on Immersive Telepresence 2002 Slide 2
Current Teleconferencing
Capture
TransportDisplay
?
International Workshop on Immersive Telepresence 2002 Slide 3
The Office of the Future
International Workshop on Immersive Telepresence 2002 Slide 4
Group Teleconferencing
• Multiple persons Multiple persons (3-4) at each site(3-4) at each site
• Life-size, Life-size, monoscopic monoscopic displaydisplay
• High-resolution High-resolution seamless seamless imageryimagery
• Active view Active view controlcontrol
• Multiple persons Multiple persons (3-4) at each site(3-4) at each site
• Life-size, Life-size, monoscopic monoscopic displaydisplay
• High-resolution High-resolution seamless seamless imageryimagery
• Active view Active view controlcontrol
Cameras
International Workshop on Immersive Telepresence 2002 Slide 5
Active View Control
Provide the best approximating view
International Workshop on Immersive Telepresence 2002 Slide 6
Active View Control
A view synthesis problemA view synthesis problem• Extract 3D geometry from a Extract 3D geometry from a
few camerasfew cameras– Less expensiveLess expensive– Hard to get good resultsHard to get good results
• Image-based method: Image-based method: capture many imagescapture many images– Looks really good on every Looks really good on every
scenescene– Need many imagesNeed many images
A view synthesis problemA view synthesis problem• Extract 3D geometry from a Extract 3D geometry from a
few camerasfew cameras– Less expensiveLess expensive– Hard to get good resultsHard to get good results
• Image-based method: Image-based method: capture many imagescapture many images– Looks really good on every Looks really good on every
scenescene– Need many imagesNeed many images
International Workshop on Immersive Telepresence 2002 Slide 7
Our Image-based Approach
• Observation:Observation:Eye level remains relatively the same Eye level remains relatively the same
during a conference sessionduring a conference session
• A compact Light Field representationA compact Light Field representation– Parameterized by a 3D function (s, u, v)Parameterized by a 3D function (s, u, v)
• Observation:Observation:Eye level remains relatively the same Eye level remains relatively the same
during a conference sessionduring a conference session
• A compact Light Field representationA compact Light Field representation– Parameterized by a 3D function (s, u, v)Parameterized by a 3D function (s, u, v)
u
v
s
t
Focal Plane
International Workshop on Immersive Telepresence 2002 Slide 8
Linear Light Field
International Workshop on Immersive Telepresence 2002 Slide 9
LLF Rendering
• Projective Texture mapping and blendingProjective Texture mapping and blending– Tessellate the focal planeTessellate the focal plane
– Project input images onto the focal planeProject input images onto the focal plane
– View-dependent blendingView-dependent blending
• Projective Texture mapping and blendingProjective Texture mapping and blending– Tessellate the focal planeTessellate the focal plane
– Project input images onto the focal planeProject input images onto the focal plane
– View-dependent blendingView-dependent blending
New view
Base image
Focal Plane
International Workshop on Immersive Telepresence 2002 Slide 10
Blending Function
V
C0 Ci CN-1C1
0
1
D
i
N-1
j j
ii
ii
ˆ
ˆ
expˆ2
2Focal Plane2
International Workshop on Immersive Telepresence 2002 Slide 11
Samples Images
PerspectiveProjection
OrthogonalProjection
(extreme case)
International Workshop on Immersive Telepresence 2002 Slide 12
Sampling Analysis
• Configuration parameters– Focal plane depth D
– Camera’s FOV
– Camera’s horizontal resolution W
– Inter-camera distance d
• Error term: pixel drift (e)
• Configuration parameters– Focal plane depth D
– Camera’s FOV
– Camera’s horizontal resolution W
– Inter-camera distance d
• Error term: pixel drift (e)
Given the configuration parameters, and a desired error tolerance e , what is the maximum depth deviation D from the optimal depth D.
Given the configuration parameters, and a desired error tolerance e , what is the maximum depth deviation D from the optimal depth D.
International Workshop on Immersive Telepresence 2002 Slide 13
Sampling Analysis – Result
International Workshop on Immersive Telepresence 2002 Slide 14
More results
• Distributed SystemDistributed System– 11 cameras11 cameras
– 6 capture PC ( 640x480)6 capture PC ( 640x480)• ROI encodedROI encoded• JPEG compressionJPEG compression
– One rendering PCOne rendering PC• Roughly 1000 x 480 Roughly 1000 x 480
outputoutput• 4-7 frames per second4-7 frames per second
• Distributed SystemDistributed System– 11 cameras11 cameras
– 6 capture PC ( 640x480)6 capture PC ( 640x480)• ROI encodedROI encoded• JPEG compressionJPEG compression
– One rendering PCOne rendering PC• Roughly 1000 x 480 Roughly 1000 x 480
outputoutput• 4-7 frames per second4-7 frames per second
International Workshop on Immersive Telepresence 2002 Slide 15
Conclusions
We presented a novel system designed We presented a novel system designed specifically for specifically for groupgroup video- video-teleconferencing.teleconferencing.
• Best approximate view for the groupBest approximate view for the group
• Photo-realistic results at interactive rate Photo-realistic results at interactive rate
• Flexible and scaleableFlexible and scaleable
We presented a novel system designed We presented a novel system designed specifically for specifically for groupgroup video- video-teleconferencing.teleconferencing.
• Best approximate view for the groupBest approximate view for the group
• Photo-realistic results at interactive rate Photo-realistic results at interactive rate
• Flexible and scaleableFlexible and scaleable
International Workshop on Immersive Telepresence 2002 Slide 16
Acknowledgements
Funding support from The Department of Energy's ASCI VIEWS Program
Sandia National Laboratories USA
Collaborators from SandiaCollaborators from SandiaPhil Heermann
Christine Yang
Corbin Stewart
Funding support from The Department of Energy's ASCI VIEWS Program
Sandia National Laboratories USA
Collaborators from SandiaCollaborators from SandiaPhil Heermann
Christine Yang
Corbin Stewart
International Workshop on Immersive Telepresence 2002 Slide 17
The End
Thank You