Worzyk FH Anhalt Telemedizin WS 03/04 Einführung - 1 Video Conference.

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Telemedizin WS 03/04Einführung - 1

Video Conference

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Definition

A video conference is a virtual meeting of two or more spatially separated dialogue partners, which can communicate in real time over audio and video with each other. At the same time all data (audio, video, text) can be digitized, handled simutanously and exchanged among the partners.

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components• Camera – Display

– Transmission of moving pictures in real time

• Microphone – Loudspeaker– Transmission of sound in real time

• Chat– Written Communication

• Whiteboard– Concurrent drawing, writing, inserting

• Share programs– using Word, PowerPoint from the partner

• Transfer of data– Transfer of any data

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Transmission

CodecCodierer/Decodierer

CodecCodierer/Decodierer

ISDNIP

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reduction of dataMPEG

motion pictures expert group

Spatial redundancyAreas with same brightness

and color can be summarized. The first pixel is accurately transferred, then an instruction for the repetitions follows

http://www.broadcastpapers.com/data/ON2Compression01.htm

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Temporal redundancySome parts in the scene do not

change from one pictuer to the next picture. So it is only necessary to transmit the changing parts of the

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Statistical Redundancy

PredictionMovements which are

known from the past are predicted to the future and only unpredictable parts of the picture are transmitted,

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DatastreamIntra picture: compleate

picture reduced by Spatial redundancy

Predicted picture: predicted by a previous picture

Bidirectional predicted picture : predicted or calculated by previous and subsequent pictures.

I B B P B B P B B I

http://bmrc.berkeley.edu/frame/research/mpeg/mpeg_overview.html

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http://www.lrz-muenchen.de/services/schulung/unterlagen/bildkommunikation/sld031.htm

http://vcc.urz.tu-dresden.de/vc-handbuch/

H.323Terminal

H.323Terminal

H.323Terminal

ISDNTerminal

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Videoconferencing Room

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ExamplesBremerhaven Berlin

DuisburgGarching

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interior design

• Sufficient seats, visible from the camera• Display must be visible from each seat• No blind area• Sufficient lightning, no mixed light (blue

daylight and red bulb light)• Acoustic shielding• Monochrome, neutral background

http://www.mcsquared.com/videoconference.htm

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Video

• Camera to track the speaker should be movable with programmable positions

• Document camera or presentation camera should be movable

• For each camera one display at the own and at the remote site

• Speakers camera should be directly above the assigned display

• Control panel

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Audio

• Shield external sound source– Traffic, engines, elevators, Air conditions,

• Avoid reverberation in the interior• Same distance to the microphone for

each speaker• A single person should use a headset• High quality loudspeakers• Mixer

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Lighting

• Illumination uniformity of the room• Diffuse light• No cast shadow• No reflection on the displays• No direct light to the camera

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During the conference

• The sound may come in delay (probably use a seperate sound connection)

• eye contact is not possible, so position camera and monitor as close as possible side by side

• Inform the partner about each action– Turning off the micro, freeze image, someone is

leaving or comming, …

• Little gesture

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Examples

http://www.onko-kids.de/Projekt/video.htmhttp://www.screentherapy.de/index.htm

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Installation of NetMeeting

• Check headphone or loudspeaker• Connect the microphone• Check the microphone• CAll NetMeeting

– No registration to the directory server

• Connect to the partner via IP address

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Weitere Informationen

http://vcc.urz.tu-dresden.de/vc-handbuch/http://www.uni-essen.de/videokonferenz/http://www.ruhr-uni-bochum.de/rz/dienste/internet/vkonf/http://it-resources.icsa.ch/SoftWare/VGuideD.htmlhttp://it-resources.icsa.ch/SoftWare/VGuideD.htmlhttps://www.vc.dfn.de/doku/vortraege/folien.dd/2_rahmenbedingungen_20020424.pdf

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Videoconference systeme in our Department

NetMeeting– One camera– ein microphone (Sound in one direction)– Transmission of

• Presentation• Shared Whiteboard• Chat

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Videoconference systeme in our Department

Interkom + Polycom2 movable CamerasCamera controll 6 MicrophonesMicrophone controll

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Konferenzschaltung

Interkom Polycom

Internet

Worzyk FH Anhalt Telemedizin WS 03/04 Einführung - 1 Video Conference.

Documents

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