chapter  2
32 Pages

The Stereoscopic Camera Unit

PUTSYOURCAMERASWHEREYOUREYESWOULDWANTTOBENOTWHERETHECAMERAS FORM FACTOR FORCES YOU TOPUT THEM4HE$ CAMERA RIGWILL BE THE ADMIRAL SHIP OF YOUR $ CAMERA mEET )TS BIG SOMETIMES BULKY EXPENSIVE SOME TIMESUNAFFORDABLE COMPLEXSOMETIMESBORDERLINEGEEKY ANDDELICATETO THE POINT OF FRAGILITY 3TILL ITS THE AIR LAND SEAMULTIPURPOSE AIRCRAFT CARRIER THATWILLNEVERFALLSHORTANDWILLALWAYSPULLOUTTHEVERY$IMAGEYOUARE LOOKINGFOR

!LTHOUGH A NEW GENERATION OF $ CAMCORDERS IS EVOLVING THEY ARE SPECIAL IZEDCAMERASTHATPERFORMBEAUTIFULLYINASPECIlCSETTINGONTHEIROWNTURF!S SUCHTHEYWILLNEVERBRINGYOUTHEVERSATILITYOFAGOODOLDBULKY$RIGˆAND TOBOOTAGOOD$RIGWILLHOSTANY$CAMERAYOUWANTORNEEDTOUSE)FTHE $0DIRECTOROR&8SUPERVISORWANTSA0HANTOMA2ED/NEORAN!22)!LEXA YOURFULL SIZE$RIGWILLHOSTIT

/VER THE NEXT FEW YEARS THE MONEY SPENT IN $ CAMERA DESIGN WILL HAVE INCREASED BY A HUNDRED OR THOUSANDFOLD 4HESE NUMBERS ARENT SURPRISING CONSIDERING HOW SCARCE THE $ CAMERA COMPANIESWERE A FEW YEARS AGO7E WILLSOONSEEANEWREVOLUTIONARY$CAMERASYSTEMEVERYTHREEMONTHS-OST OF THEMWILLACTUALLYOFFERAMAZINGNEW FEATURESANDWILLBE THEPERFECT TOOL FOR A SPECIlC SHOOT ANGLEPROJECTORBUDGET(OWEVEROURUNDERSTANDING IS THATTHE$RIGTHATHOSTSREGULARORSPECIALIZED$CAMERASANDMOVESTHEM DYNAMICALLYBEHINDABEAM SPLITTINGOPTICALDEVICEISHERETOLASTˆEVENIFITS FORMFACTORPRICEANDCOMPLEXITYWILLSHRINKSIGNIlCANTLY

/URMAIN REASON FOR HOLDING THIS POSITION IS THE SAME REASONWE THINK $ GLASSES ARE HERE FOR GOOD BASICALLY THERES ONLY SOMUCH YOU CAN DO TO GET AWAY FROM THE LAWS OF PHYSICS AND OPTICS 3TEREOSCOPIC $ IS MADE OF TWO DISCRETE IMAGESDESCRIBINGTWOPOINTSOFVIEWEVENIFWETHROWTHOUSANDSOF ENGINEERSMILLIONS OF DOLLARS AND BILLIONS OF COMPUTING CYCLES AT THE ISSUE WEWILL STILL ENDUP LOOKINGAT THESE TWOVIEWPOINTS )F YOUCAN RECORD THEM RIGHTAWAYYOUDOYOURSELFAGREATFAVOR!S$VISUALEFFECTSGURU4IM3ASSOON SAYSh3TEREOSCOPIC$ISAVISUALEFFECT)FYOUCANSHOOTITYOUSHOULDSHOOT IT0ERIODv

.OWTHATWEHAVEMADETHECASEFOR$RIGSLETSACKNOWLEDGEHOWCOMPLEXTHE SYSTEMISANDEXPLOREHOWANDWHYITCAMETOTHATLEVELOFCOMPLEXITY!FTERALL A$CAMERA IS JUSTAPAIROF$CAMERASSTITCHED TOGETHER'ETAWOODPLANK TWOSCREWSANDSOMEDUCTTAPEANDTHEREYOUHAVEIT4OBEHONESTTHATSPRETTY MUCHHOWMOSTSTEREOGRAPHERSSTARTEDINTHEIRYOUNGERYEARS4HERICHERHADALU MINUMPLATESANDTHESMARTERGOTSLIDERSBUTWEALLSTARTEDWITHTHEBASICS!ND THEFEWOFUSWHOPURSUEDTHEJOURNEYALLTHEWAYTOTHECURRENTSTATE OF THE ART $RIGSENDEDUPWITHTHESAMESOLUTIONABIGBULKYCAMERAASSEMBLYREVOLVING AROUNDAHALF MIRRORHOSTINGADREADEDNUMBEROFMOTIONCONTROLMAGICBOXES ANDMOST LIKELY CONNECTED TOAN IMAGEPROCESSINGBEHEMOTH(OWDIDWEALL END UP AT THE SAME POINT EACH ONE FOLLOWING OUR VERY OWN PATH ,ETS FAST FORWARDYEARSIN$CAMERADESIGNTOUNDERSTAND &IRST THEREWERE THElLM CAMERA RIGSDESIGNED FOR THEMEPARKMOVIES IN THE S3OMETIMESCARVEDOUTOFASINGLEPIECEOFALUMINUMTHEYHELDTOGETHER TWO CAMERAS AND THE HALF MIRROR SPLITTING THE LIGHT BEAM 4HEYWERE BEAUTI FULANDACCURATEBUTHEAVYEXPENSIVEANDNOTTHATVERSATILEWITHNODYNAMIC INTER OPTICALDISTANCE #HANGECAMEINTHESWITHTHENEWWAVEOFELECTRONICIMAGINGANNOUNC ING THE DIGITAL REVOLUTION#AMERA HEADS COULD BE DETACHED FROMPROCESSING ANDRECORDINGUNITSANDMOTIONCONTROLSTARTEDTODEMONSTRATEITSCAPACITIES !T THATPOINTA FEWENGINEERSOR CINEMATOGRAPHERSON THEPLANETESTABLISHED THE$EQUATION

%LECTRONICIMAGINGMOTIONCONTROLPERFECT$IMAGES

4HEYSTARTEDDEVELOPINGWHATWOULDEVENTUALLYBETHEBLUEPRINTSFORTHE$RIGS YOUSEE TODAY4HATDESIGNWASDEVELOPED THEHARDWAYBYGETTINGBACK FROM LOCATIONLATEANDOFTENEXHAUSTEDWITHLESSTHANOPTIMALPICTURESANDCURSING ABOUTNOTHAVING THE$TOOLS THATWOULDMAKE ITEASIER2EMEMBERPRODUC ING$ALWAYSSTARTSBYPUTTINGTWOCAMERASTOGETHERANDSHOOTING)NTHATPRO CESSONEDISCOVERSTHELIMITATIONSOFTHESYSTEMBUILDSSOLUTIONSTOCIRCUMVENT THEM AND PROGRESSES TOWARD HIGHER $ QUALITY EASIER PRODUCTION SCHEDULES ANDMORERESILIENCETODEALWITHTHEUNEXPECTEDISSUESTHATCONTENTPRODUCTION ALWAYSRANDOMLYYETSTEADILYGENERATES )F YOU HAD BEENMAKING $MOVIES AND THEREFORE $ CAMERAS FOR THE LAST YEARSHEREISWHATYOUWOULDHAVEDISCOVERED Step one: 9OU NEED TO MOTION CONTROL THE LEFT AND RIGHT CAMERAS RELATIVE MOVEMENTTOGENERATEGOOD$IMAGESBECAUSE 1. #AMERAS NEED PERFECT ALIGNMENT REQUIRING 89: AXIS TRANSLATION AND ROTATIONS

2. /NENEEDS TOBEABLE TOSETUPTHE INTER OPTICALDISTANCEANDCONVERGENCE ALMOSTINSTANTLY

3. /N SHOTS WHERE THE CAMERA OR THE ACTION IS MOVING INTER OPTICAL AND CONVERGENCEHASTOBEDYNAMIC

Step two:9OUREALIZETHATYOURINTER OPTICALISTOOWIDE)NMOSTMOVIESSHOT IN INTER OPTICAL ISUNDERHALF THEHUMANINTER PUPILLARYDISTANCEWHICH ISABOUTTHREECENTIMETERS4HISMEANSTHATTHECAMERASNEEDTOBECLOSERTHAN THELENSESWIDTH

1. #AMERASNEEDTOSHOOTTHROUGHA DEGREESHALF MIRROR 2. 4HEMIRRORHASTOBEASURFACEMIRROR 3. -IRRORSAREEXTREMELYPRONETOGETTINGDUSTY 4. !MIRRORISNOTAPERFECTPLANEITBENDSUNDERITSOWNWEIGHT 5. 3URFACEMIRRORSHAVECHROMATICASYMMETRY 6. -OST IMPORTANTLY THEMIRRORS SURFACE IS FRAGILE ANDHITTING ITWITHA LENS CANSCRATCHIT

Step three:9OUNEEDTOUSEZOOMLENSESBECAUSECHANGINGLENSESISACOMPLEX TASKONAMIRRORRIG(OPEFULLYYOUAREALREADYINTHELATESANDTHENEW ($ZOOMSARESHARPENOUGHTOBEUSEDASADJUSTABLEPRIMES7HENZOOMING INWITHYOUR$RIGYOUDISCOVERTHAT

1. :OOMPROGRESSIONISNOTLINEARANDCHANGESFROMLENSTOLENS 2. 4HEOPTICALAXIS SHIFTS ALONGAPROGRESSIONAND THAT SHIFT ISDIFFERENTWITH EVERYLENSYOUTRY

3. !S A RESULT EACH LENS PAIR HAS SPECIlC ALIGNMENT REQUIREMENTS THAT VARY WITHFOCALLENGTH

Step four: 9OU HAVE NOW REACHED THE EARLY S AND COMPUTING POWER IS SOONTOBECOMEACOMMODITY9OUSAFELYASSUMEYOUCANBUILDZOOMLOOK UP TABLES: ,54S THATUSETHE89:MOTIONCONTROLSTOALIGNTHECAMERASOPTICAL AXIS(ERECOMESANEWBATCHOFBADNEWSHOWEVER

1. -ANUALLYGENERATINGTHE: ,54ISATIME CONSUMINGPROCESS 2. 9OUSHOULDMANUALLYGENERATETHE: ,54EVERYTIMEARIGISASSEMBLED

4HAT LASTPOINT SHOULDHAVEYOURAISINGYOUREYEBROW7HATDOES THISMEAN )TMEANSTHATIFYOUTAKETHEVERYSAMESETOFEQUIPMENTANDREBUILDTHEVERY SAMERIGYOUWONTENDUPWITHTHEVERYSAMERESULTS&IRSTASSUMINGYOUCAN PERFECTLYREPEATPROCEDURESINMOVIEAND46PRODUCTIONISNOTSUCHASAFEBET 3ECONDWENEEDTOTALKNUMBERSHERE9OUWANT TOGET TO LESS THANACOUPLE OFPIXELSOFVERTICALDISPARITYONYOURlNAL IMAGE7HEN THE SENSORHAS LINESOFPHOTOSITESONA INCHSENSORONELINEISTHOFMMCLOSE TO THREEMICRONS 4HE LARGER DIGITAL SENSOR THE 0HASE/NE 0 WITH LINESONMMHASAWHOPPINGMICRONSPERPIXEL4OGIVEYOUACOMPARI SONBASE A HUMANHAIR IS TO MICRONS 9OU CANNOT BUILD AMECHANI CALASSEMBLYWITHMOVINGPARTSANDEXPECTALIGNMENTlGURESTOBEPREDICTABLE WITHINAFEWMICRONS

1. 4HEORDEROFMAGNITUDEISTOMOVECAMERAANDLENSESWEIGHING+GATUP TOCMSEC

2. )NERTIAANDMOMENTUMEFFECTSSETAPHYSICALLIMITTHATYOURHARDWAREMAGI CIANSWILLNOTBEABLETOBREAK

9OU STILLNEEDANAUTOMATIC LENSESMATCHING TOOL ANDYOUBUILDYOUR IMAGE ANALYSISTOOLS 1. !UTOMATIC : ,54 CREATION IS A QUITE COMPLEX IMAGE PROCESSING PROBLEM INVOLVINGCOPLANARGEOMETRY

2. /VERATYPICALSHOOTINGSESSIONTHERMALDILATATIONCANCHANGEA: ,54ORA CAMERAGEOMETRY*USTTOUCHINGACAMERAMAYBEENOUGHTOCHANGETHECOR RECTIONVALUES

Step five: 9OUHAVE NOW SUCCESSFULLY REACHED THE LATE S AND YOU ARE THE INVENTOROFONEOFTHEFEWWORLD CLASS$CAMERASYSTEMS"YNOWITISOBVIOUS THAT$CINEMAISGOINGMAINSTREAMAND$46ISRIGHTAROUNDTHECORNER"OTH REQUIRETHATYOUPRODUCEPERFECT$IMAGERYANDBOTHWONTCOPEFORLONGWITH THEIDEATHATEVERY$SHOTISAN&8SHOTTHATSHOULDBEGROOMEDINPOST 1. -ANUAL DEPTH SETTING BY HUMAN OPERATORS IS NOT ADAPTED TO $ 46 PRODUCTIONS

2. &ULLFRAMEANALYSISANDCORRECTIONSHOULDBEPERFORMEDINLESSTHANMS FORLIVE46

3. !LLUNITSINVOLVEDINAMULTICAMERAPRODUCTIONSHOULDBEDEPTH COORDINATED !FTERREADINGTHISLISTYOUMAYWONDERIFITSWORTHITˆPERHAPSWEAREOVERDO INGITANDTHEANSWERMAYBETOSTARTFROMASIMPLERPLACEORTOGETMOREhlX ITINPOSTvPOWER

Description and Vocabulary )N&IGURESYOUCANSEETHEMAINPARTSOFA$MIRRORRIG ■ 4HEHALF MIRRORWHICHSPLITSTHELIGHTPATHINTOTWOOPTICALAXES ■ 4HETRANSMISSIVECAMERAWHICHRECORDSTHELIGHTPASSINGTHROUGHTHEMIRROR ■ 4HEREmECTIVECAMERAWHICHRECORDSTHELIGHTBOUNCINGONTHEMIRROR ■ 4HEHOODWHICHPROTECTSTHEMIRRORFROMCATCHINGSURROUNDINGLIGHTSNOT SHOWN

■ 4HEINTER OPTICALANDCONVERGENCEMOTIONCONTROLLERS ■ 4HEZOOMFOCUSANDIRISCONTROLLERS

Functions and Features 7HATDOESA$ RIGDO ESSENTIALLY!SWEHAVE SEEN IT KEEPSAPAIROF CAM ERAS TOGETHER AND THENMOVES THEMWITHMICROSCOPIC ACCURACY )TS ALL ABOUT MOTION CONTROL -# !T A BAREMINIMUM YOUWANT A RIG TO ALLOW FOR EASY CAMERAALIGNMENTWHICHWELLCALLmechanical control.4HENYOUWANTTOBEABLE TOMOVECAMERAS RELATIVE TOEACHOTHERBYCRANKINGWHEELSAT THEVERY LEAST ORBYRUNNINGMOTORSPREFERABLY WHICHWELLCALLdynamic control.%VENTUALLY YOU WANT SUCHMOVEMENTS TO BE AUTOMATIZED WITH intelligent motion control THATTAKESCARESOFTHELENSESOPTICALSHIFTSANDULTIMATELYYOUWANTTHATINTEL LIGENTRIG TOOBEYARTISTICORDERS LIKEhMOREDEPTH IN THEBACKvASOPPOSEDTO TECHNICALREQUESTSLIKEhCONVERGECLOSERv

4HESEARETHETHREELEVELSOFFUNCTIONSA$RIGSHOULDOFFERMECHANICALCON TROLDYNAMICCONTROLANDINTELLIGENT-#

3D RIG, LEVEL ONE: MECHANICAL CONTROL AND CAMERA ORIENTATION

-ECHANICAL CONTROL OF A CAMERA POSITION IS A BAREMINIMUM REQUIREMENT FOR GOOD$SHOOTING4HISCONTROLINCLUDESTHEABILITYTOREGISTERCAMERASTOGETHER )NTHEORYTHISMEANSCONTROLLINGTHREEAXESPERCAMERAINBOTHTRANSLATIONAND ROTATION4HISAMOUNTSTOATOTALOFDEGREESOFFREEDOM/BVIOUSLYONLYONE CAMERAPERFORMINGALLMOVEMENTSWOULDBEENOUGH/UTOFTHESESIXREMAINING AXESTHREESHOULDBElXEDANDTHREESHOULDBEADJUSTABLE

4HElXEDMECHANICALCONTROLSARETHECAMERAHEIGHTDEPTHPOSITIONANDROLL AXISWHICHARETOBElXEDONLYONCE

4HEADJUSTABLEMECHANICALCONTROLSARE

■ 4HE DISTANCES BETWEEN THE CAMERAS CALLED inter-axial, inter-ocular, interoptical,ORstereo base.