Vinay.RMar 28 2009

Networked Media Lab

GIST

Multi-site Visualization Sharing

Contents

Introduction Approach to share visualization Visualization sharing environment Sharing scenarios Proposed solution Prototype implementation Test evaluation Conclusion and future work

Introduction

Visualization of massive, complex data over multi-display (aura, chromium)

Collaborative environment for visualization SAGE (scalable adaptive graphics environment)

Suitable for images and videos CGLX (cluster graphics library)

Suitable for graphics apps SMeet (smart meeting space)

Supports heterogeneous displays Share visualization ?

Concurrent view of visualization

Concurrent view

Node 3

Node 4

Node 1

Node 2

Approach to share visualization

Collaborative visualization abstraction Classify deployment scenarios Understand requirements Architect solution in SMeet environment Implement and test

Visualization sharing environment

S a collaboration session

NSset of participating nodes of a session S

MSset of media sources of a session S

DSset of display elements of a session S

VSset of visual elements of a session S

Mn set of media sources of a node n ∈NS

Mnm

a media source in Mn

Dn set of display elements of a node n∈ NS

Dnd a display element in Dn

Vnd set of visual elements displayed on Dn

d

Vnd,v a visual element in Vn

d

Rnd whole screen of Dn

d

Rnd,v screen region of Vn

d,v

Rnd

(x,y,w,h)rectangle region of Dn

d starting from (x,y) with a width (w) and a height (h)

MA1

MA2

MA3

MB1

MB2

MC1

VBa,1

Node A

Node B

Node C

Node A

Node B

Node C

Node D

VBa,2

VBb,1

VBb,2

VAa,1

VAa,2

VAa,3

VCa,1

VCa,2

VDa,1

DAa

DBa

DBb

DCa

DDa

RAa(x,y,w,h)

RBb,1

RDa

Sharing scenarios

Single-session, Single-interest

Single-session, Multi-interest

Multi-session, Multi-interest

VAa,1 VAa,2 VBa,1

Node A Node B Node C

RBa,2

VBa,2 VCa,1 VCa,2

MA1 MB

1

Session

InterestABC

InterestAB

InterestACInterestBC

VAa,1 VAa,2 VBa,1

Node A Node B Node C

VBa,2 VCa,1 VCa,2

Session

MA1 MB

1 MC1

RBa,2

InterestBC

VAa,1 VAa,2 VBa,1

Node A Node C

VCa,2

SessionAB

MA1 MB

1 MC1

RBa,1

MB2

VBa,2

SessionBC

Node B

VBa,3

InterestAB

example

Single-session, Single-interest

Single-session, Multi-interest

Proposed Solution(high level view)

Add replication layer to replicate media contents to all the nodes

Proposed Solution(detailed view)

Current SMOD structure

Proposed Solution(detailed view)

Modified SMOD structure Multiple clustered displayers Replication manager module Display configuration module

Display resolution mapping

Without mapping

Simple mapping

Mapping algorithm

1. Find source to dest. total display resolution ratio

2. Calculate dest. VE’s origin point (bottom left) based on ratio

3. If source VE’s width is out of dest. display’s horizontal range

4. Then adjust dest. VE’s width to maximum

5. Else dest. VE’s width is equal to source VE’s width

6. If source VE’s height is out of dest. display’s vertical range

7. Then adjust dest. VE’s height to maximum

8. Else dest. VE’s height is equal to source VE’s height

h_src

h_dest

y_src

x_src

v_src

v_desty_de

st

x_dest

ht_src

w_src

ht_dest

w_dest

VE – visual element

Prototype Implementation

“Single session, Single interest” scenario is implemented for now.

Replication Manager written in C++

Testbed

Evaluation

Images ranging from 2 mega pixels to 35 mega pixels consume approximately 1 to 2 seconds

Images are shared only one time i.e. pixels are replicated only once

Video streams of resolution 1280x720 are captured at a frame rate of 30 fps.

Delay to replicate does not cross more than 90 milliseconds

No abrupt variations in network delay (frames are generated at a constant rate )

0

0.5

1

1.5

2

2.5

1k x 2k 3k x 2k 4k x 3k 5k x 3k 6k x 4k 7k x 5k

Image Resolution (pixels)

Tim

e (s

econ

ds)

Related Work

SAGE Visualcasting broadcasts media

contents directly to all the end-point display nodes

Streaming-based VNC solution*

single-master multi-slave configuration (not useful for collaboration)

*Zhongding Jiang et al., “A streaming-based approach for remote interaction of the multi-channel display system for group users,” Multimedia and Expo, 2008 IEEE International Conference on , vol., no., pp.397-400, 2008.

Conclusion

Approach to design a flexible multisite visualization sharing system

Described different scenarios in a visualization sharing environment

Visualization sharing system implemented on SMeet

Future Work Share selective region of tiled display area Share interactions (keyboard, mouse, pointer) Test with more than two nodes Develop performance model