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DesigningRoomLightingForVideoconferencingThenewDesignGuidefromIESNAistheclosestthingproAVhastoaninternationalstandardforvideoconferencinglightingdesign.Source:PROAVMagazinePublicationdate:December1,2005ByTimCape,CTS-DWhiletheultimategoalinvideoconferencingisgoodinteractivitybetweennear-andfar-endrooms,onemonlightingdesignproblemcanbesummedupinaquestionthat'sremainedconstantthroughouttheevolutionofvideoconferencingtechnology:Howcanyouprovidegood,fortablelightingtooptimizethecameraandvideocodecoperationinanarchitecturalenvironmentratherthaninastudio?Althoughit'safairlysimplequestion,theanswercanbequiteplicated.Theremustbesomelightintheroomofthespaceyou'redesigningjustforthecameratoproduceanimage,butmakingthatimagelookgoodwhilemaintainingagoodprojectedvideoimagecanbeeasiersaidthandone.Ontopofjustgettingthecameratoproduceadecentimage,youalsohavetobeconcernedaboutwhatthecodecwilldotothatimage(particularlyatlowbitrates,puttingmoreconstraintsonnotjustthelightingdesignbutalsotheinteriordesignoftheroomitself—onceagaingoingbeyondthetenetsofabasicAVsystem.Upuntilnow,AVprofessionalshaven'thadmuchconsistentguidanceonvideoconferencingroomlightingdesign,butthenewdesignguide,offeredbytheIlluminatingEngineeringSocietyofNorthAmerica(IESNA,givesthemanauthoritativeplacetostart.ThenewdesignguideIndevelopmentsince2002,the“VideoconferencingLightingDesignGuide,”DG-17-05,isnowavailableforpurchasethroughtheIESNAwebsite(.iesna.org.Itincludesawiderangeofremendedcriteriaandgeneralremendationsforapproachestolightingforvideoconferencingfacilities.It'sspecificallyorientedtowardsmall-tomid-sizedvideoconferencingroomswithasinglecameraaxis(fromdisplaystoseatedparticipants.Itdoesn'tspecificallycoverdual-axisroomsthatincludeapresenternearthedisplaysorlargerfacilities,thoughmuchofthecriteriacanbeappliedtothiswiderrangeofrooms.TheGuideisintendedtosomeextentfordesignersbothwithandwithoutabackgroundinlightingdesign.TheolddesignproblemBeforeansweringthequestionpresentedaboveabouthowtooptimizethecameraandvideocodecoperationinanarchitecturalenvironment,youmustunderstandseveralbasicandsometimesconflictingrequirements.Andit'snotjustabouttheluminairesthatemitthelight,it'sabouttheroom,too.Theprimarytasksintermsoflightingare:1/6
Lighttheparticipantsforgoodvideo.Thisinvolveslimitingthevariationinlightlevelenoughtoallowthecameratoreproducethefullrangeoflightandshadowinthepicture.Atthesametime,thereneedstobeenoughvariationinthepicturetokeepitfromlooking“flat”withnoshadowordepth.Lighttheroomtoplementtheparticipants.Thismeanspayingattentiontothelightingforthewalls,floor,andceilingareasthatmightbeinthecameraview.Coordinatetheroomfinishesfromthestandpointofcolor,contrast,andpattern,andhowtheyrelatetothepeopleinthepicture.Thisalsoinvolvesconsiderationofthetypeoffinish,andhowitmayaffecttheimagepickedupbythecameraandtransmittedtotheremotesite.Forexample,reflective,orspecular,finishessuchaschromecancreateproblemsforthecamerabycreatinganexcessivelybrightspotintheimage.Sometimestherearemoreparticularconstraintsplacedonthelightingsystemwhenspecialcamerasorhigherthannormalcolorrenderingareneededforspecializedapplicationslikeretail,fashion,andsomemilitaryenvironments.However,thebasicsaboveapplytoanyvideoconferenceroomandarediscussedintheGuideThefundamentalsTocreateanenvironmentthatworkswellforvideoconferencing,designersmustaddresssomefundamentallightingparameters.ForthoseinproAV,thismaymeanbeingfamiliarwithatleastthebasiclightingtermsyou'llencounterinalightingdesignproject.WhiletheAVdesignermaybequalifiedtobethelightingdesignerinsomecases,it'smorelikelythatheorshewillbeprovidingcriteriatoalightingorelectricalconsultantwhowillthendesignthelightingunderaseparatescopeofwork.Ineithercase,theAVdesignerneedsatleastsomebasiclightingknowledge.Tobeginworkingwithlighting,somebasiclightingtermsshouldbeunderstood.Someofthetypicaltermsusedindiscussinganddesigninglightingsystemsarerelatedtothoseforprojectionanddisplaytechnologies.Illuminanceisthelightlevelincidentonasurfaceorplanefromasourceorsources.It'sexpressedinlux(lumenspersquaremeter—thepreferredunitofmeasureorfootcandles(fc,lumenspersquarefoot—themoreobsoleteunit.Onefootcandleequals10.76lux.It'susefultonotethatexactconversionsshouldbeusedwhenreportingmeasurements,butwhenbotharegivenascriteriaasimpleconversionfactorof10isoftenusedinsteadof10.76.Luminanceistheluminousintensityfromasurfaceinaparticulardirection.Luminancemaybethoughtofinthisdiscussionasthelightreflectedfromasurface.It'sexpressedascandelaspersquaremeter(footlambertsinthemoreobsoleteEnglishunits.Luminairereferstoapletelightingassemblyincludingthehousing,reflectors,andlamps.Onlywhenit'sinstalledisthiscorrectlyreferredtoasalightfixture.2/6
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