© 2002 Lehrgebiet Rechnernetze und Verteilte Systeme Architecture of a shared-image electronic whiteboard in telemedicine Projekt INTER-FACE Michael Fromme

© 2002 Lehrgebiet Rechnernetze und Verteilte Systeme

Architecture of a shared-image electronic whiteboard in telemedicine

Projekt INTER-FACE

Michael Fromme

Lehrgebiet Rechnernetze und Verteilte Systeme

Universität Hannover

Michael Fromme© 2002 Lehrgebiet Rechnernetze und Verteilte Systeme Slide 2

Outline

• Conferencing scenarios in INTER-FACE• Network infrastructure in INTER-FACE• Whiteboard software and images• Architecture for whiteboard communication• System architecture and implementation• Conclusion


Project INTER-FACE

• Topic– maxillofacial surgeries with bone rearrangements

– computer-aided planning of the surgery

– pre-operative treatment by orthodontists

– multiple consultations of surgeon and orthodontist necessary

• Aim– allow some consultations with the aid of a video conference

– build a working environment for that case

– evaluate working environment with respect to• efficiency• practical requirements• patient experience


Computer aided surgery planning

pre-surgerycomputer-aided

surgery planningpost-surgery


Technical Equipment

Orthodontist equipment• Video communication terminal (H.323)• PC with whiteboard• intra-oral camera


Communication structure

H.323 MCU

(Hanover)

IWB Server

(Hanover)

Orthodontist

(Munich)

One or more specialists

at university hospitals

(Munich, Düsseldorf, or Stuttgart)

point-to-point or

multipoint conference


Network infrastructure

Düsseldorf

Stuttgart

Munich

Orthodontists

(Munich)

Hanover

St. Augustin

H o

s p

i t

a l

s

SDSL

1Mbps

GWiN

620 Mbps

decix / DFN


Image Whiteboard functionality

• Load and display common image formats

(TIFF, JPEG, BMP, FlashPix, PNG, PNM, GIF)

• Image annotations• Image manipulations

(zoom, pane, color effects)

• Distribute and synchronize image and annotations

• Use color management functionality

• Session management• Print and save images


Every device processes color in a different way

ICC Color Management

We need additional processing for a true reproduction of color.

This processing is done by a color management system.

printer

computer

scanner

digital Kamera

screen


Color Management

printer

computer

scanner

digital Kamera

screen

device dependend

color space

device dependend

color space

device independend

color space

input profile

output profile

screen profile


Color Management in IWB

• Features– uses color management facility of Java Advanced Imaging API– images can be loaded together with explicit input profile– images are distributed and processed in the device independent color space

SRGB

• Notes– need of accurate profiles for input / output devices, they can be generated

with a spectral photometer and calibration software– many manufacturer provide profiles for their devices


IWB Network Communication

• Multi-point conferences with IWB– IP multicast capable, but

works in IP multicast networks

only

– TCP and central server needed for SDSL connected partners or partners behind firewalls

• Multi-point protocol features– session handling

– reliable transmission

– startup syncronization (image bootstrap) with unicast


System architecture

JAI 1.1

LRMP

TCP UDP

User-InterfaceImage-Handling Group Control

Data Distribution Layer

Operating System

Remote Object InvocationJava 2D

Java JVM 1.3.1


Remote Object Invocation

Object method call

Object serialization

transport connection

Request/Reply

Object method call

Object de-serialization


ROI Transport Protocols

• Unicast– TCP connection for reliable transport– UDP connections (variants: reliable, rate-limited)

• Multicast– UDP (unreliable)– Lightweight Reliable Multicast Protocol LRMP (Inria)– Reliable Multicast Framework RMP (TASC)

• Multicast simulation– transport connection is TCP from peer to server– central router component simulates unicast / multicast transmission

• ROI Object Method Invocation Semantics– normal call (Unicast only)– one-way call– reliable group call with one return value (first value selected)– group call with return value array


Session Initiation Example

Iw bC onta inerIw bServer

Iw bC onnection

w elcom e(call)

getG roupM em berList().addM em ber(ID 0,ID 1)

create()

getU pdate(unicastC lientStub)

* [a ll shared im ages] setIm ageD ata(SharedIm age)

* [a ll shared annotations] setAnnotation(SharedAnnotation)

* [a ll docum ents] updateR eady(D ocum ent)

jo inG roup(getLocalM em ber())


Conclusion

• Multi-user whiteboard– uses group-oriented middleware

– based on Java Image API

• Related information– http://www.rvs.uni-hannover.de/projects/interface { german }

– http://www.rvs.uni-hannover.de/products/iwb

• Further work– better adoption to the medical environment

– integration for medical software (surgery planning)

– user interface, input formats and functionality

– security, e.g. encryption of network communication

Documents

© 2002 Lehrgebiet Rechnernetze und Verteilte Systeme Architecture of a shared-image electronic whiteboard in telemedicine Projekt INTER-FACE Michael Fromme