Autostereoscopic 3D Displays.docx

Autostereoscopic 3D Displays.docx

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Autostereoscopic3DDisplays

Autostereoscopic3DDisplays

EliSoman

4/8/2008

TableofContents

1.Introduction1

2.Background1

3.TypesofDisplays1

3.1VolumetricDisplays2

3.2LightFieldDisplays3

3.3ParallaxDisplays4

3.4HolographicDisplays5

3.5VarrierVRDisplays5

4.CreatingImagesandMediaforAutostereoscopicDisplays6

4.1CreatingImagesforHolographicDisplays7

4.2CreatingImagesforVolumetricDisplays7

5.UsingImagesandMedia8

6.UsesforAutostereoscopicDisplays9

7.Conclusion10

WorksCited11

AppendixA:

ReviewQuestions12

1.Introduction

Whatdoesautostereoscopicmean?

Itmeanshavingtheabilitytoseetwoseparateimagesofthesameobjectatthesametimewithoutanytypeofexternalassistance.Thetwoseparateimagescomefromyourleftandrighteye.Eacheyeseesaseparateimageinstereo,automatically,hence,autostereoscopic.Thisideaisbeingputintousealongwiththree-dimensionaldisplays.

Themostcommonwaytoview3Dimagesisthroughtheuseofspecialpolarizedglassesorspecializedequipmentthatyouwearonyourhead.Thiscanbecumbersome,unnatural,andcantakeawayfromtheviewer’s3Dexperience

（1）.

Autostereoscopicdisplaysallowviewerstoseeobjectsbeingprojectedin3Dwithouttheneedforspecialeyewear,headgear,orotherwearabledevices

（2）.Thisleadstoamorefreeandnormalviewingexperience（3）.Mostautostereoscopicdisplaysalsoallowformultipleviewersandcancreatemoreofa“television”experience.Thesedisplaysareveryattractivebecausetheyofferthebestrepresentationofreallifeobjectsbyallowingtheviewertoexperiencenotonlyexcellentdefinitionandcolor,butdepthaswell（4）.

Therearesomemisnomersaboutthesedisplays.Besuspiciousoftechnologiesclaimingtoproduce3Dimagesinmidair,thisisimpossibleduetosomethingcalledphysics.Toseeinthree-dimensionslightparticlesneedsomethingtobounceoffof,beinfrontof,bebehind,orbewithinsomesubstancetocreateanimage.Therehastobesomesortofmaterialtogetinthewayofthephotonstoallowthemtoreflectlight（4）.Thistutorialwillgiveyouabetterideaofwhatisinvolvedincreatingthese3Ddisplaysandthetypesofmedianeededforusewiththesedisplays.

2.Background

Peoplehavebeenexcitedaboutviewingimagesinthree-dimensionssincetheinventionofthestereoscope,whichwasthefirsthandheldthree-dimensionalpictureviewer（4）.Thefirstparallaxstereogramwaspatentedin1903byF.E.Ives（5）.Anotherinventionthatcreatedexcitementinthisareawastheintroductionofpaper3Dglasseswithredandbluelensestoviewmoviesin3D.Thisphenomenonsweptthenationandwasstartedinthe1950’s（4）.Mostrecently,thesepaperglasseshavebeenreplacedwithplasticframesandpolarizedlenses,whicharebeingusedinthemeparksandforsomefamilymovies.

Sincethe1970’sresearchershavebeenlookingforwaystocreate3Ddisplaysthathavetelevisionlikequalities.Thisisalsoreferredtoas3DTV.Thesequalitiesincludetheabilityformultipleviewers,norequiredheadgear,andtheabilitytowatchlivebroadcasts.3DTVisexpectedtobethenextrevolutionintelevisionandmayverywellreplacethecurrentHDTVstandard

（2）.

Forthesedisplaystoworktheyneedtoreproducethevisualcuesthathumansusetoseeinthree-dimensions.Weuseseveraldifferenttypesofvisualcuesforthree-dimensionalsight,whichinclude:

motionparallax,binocularparallax

（2）,andaccommodation（6）.

Binocularparallax,alsoknownasstereopsis,referstoeacheyeseeingadifferentimageofthesameobject.Thiscanbeobservedbyclosingoneeyeandseeingoneimage,thenclosingtheothereyeandseeinganotherimage.Motionparallax,alsoknownasocclusion,referstotheeffectofseeingdifferentimagesbymovingthehead

（2）.Thiscanbeobservedbylookingatanobjectfromadistanceandthenmovingyourheadbackandforth.Bydoingso,youwillseedifferentportionsofthebackgroundbehindtheobjectbeingviewedintheforeground.Occlusionisoneofthemostpowerfulcuesweuseforseeinginthree-dimensions.Anothercue,whichisaweakcue,istheabilitytoquicklyfocuslightraystomakeaclearimage.Thisiscalledaccommodation.Itisbestwhenviewingobjectsfromasmalldistanceandweakensaswegetolder.Theabilitytorecreatethesevisualcueswithautostereoscopic3Ddisplaysinaneffectiveandreasonablemannerisparamounttothesuccessofthesedisplays（6）.

Computerscienceandtechnologyarenotadvancedenoughtomakethesedisplays,andthemediarequiredtousethem,affordabletothepublic,butautostereoscopicdisplaysdoexistforconsumerpurchase.Theuseofthesedisplayscouldcreatehugeadvancementsinsociety,notonlyintheentertainmentrealmbutinmanyotherfieldsaswell,including:

informationpresentation,military,telecommunications,medicine,remoteviewing,andart

（2）.

3.TypesofDisplays

Thereareseveraltypesofautostereoscopicdisplays,whichinclude:

volumetric,parallax,holographic,andafewothers.Thereareseveralmainattributesthatmakecertaindisplaytypessuperiortoothers.Oneistheabilityformultipleviewersatthesametime,theseareknownasmulti-viewerautostereoscopicdisplays.Thisisoneoftheultimateattributesdesiredinthesetypesofdisplays.Thisallowsforanyonetowalkuptothedisplayandviewthethreedimensionalmediabeingdisplayedwithoutrecalibratingthedisplay,requiringheadtracking,orwearinganyspecialdevices（3）.

Headtrackingreferstotheabilitytomonitorwhereaviewerisinreferencetothedisplay.Thevieweristrackedbywearingsomesmalldevicethatiscapableofbeingfollowedbyatrackingsystemconnectedtoacomputer.Thecomputerwilldecidewhattodisplayastheviewermovesaroundthedisplay.Someofthesedisplayswillshowabetterimageifheadtrackingisinvolvedandsomerequireitforthedisplaystoworkproperly.Thisisanobviousdisadvantagebecausethisusuallyonlyallowsforonepersontoviewthedisplayin3Datatime（3）.

Eachtypeofdisplayhastheirbenefitsanddetriments.Thereiscurrentlynodisplaytechnologythathasalltherequiredfeaturesthatmakeuptrue3DTVexperience,buttherearesomethatgetveryclose.

3.1VolumetricDisplays

Volumetricdisplaysarealsoknownasvolumedisplays,slicestackingdisplays,spatialdisplays,andspacefillingdisplays（4）.Volumetricdisplaysusesomeobjectorsubstancetofillorscanathree-dimensionalcasing,andinsomecases,voxelsareusedtodisplaytheimage.Voxelsarethree-dimensionalpixelsthatareusedinsome3Ddisplays.Theextradimensionallowsfortheviewertoseedepthcues.Thevoxelcanbecomparedtothe2Dpixel.Throughtheexcitementofthese3Dpixelsa3Dimagescanbecreated

（2）.

Theimagecreatedbyvolumetricdisplayscanhaveaghostlikesee-througheffect,whichtakesawayfromthedefinitionoftheobjectbeingdisplayed.Thesedisplayscanonlyreproducealimitedamountofcolors.Currentlythesedisplaysareonlyabletocreatemonochromeimages.Thislimitsthedisplay’sabilitytoreproduceimagestakenoutdoorsorthosewithalargelightfieldcontainingmanycolors.Thislimitedrangeofcolorsalsoaffectstheabilitytodisplayocclusioncues

（2）.

Thereareseveraltechnologiesthathavebeendevelopedtocreatethesetypesofdisplays.Onetypeisthevarifocalmirrordisplay.Thisdisplayusesamirrorthatiscoatedwithamembrane.ThecoatedmirroroscillateswhileaCRTdisplaysanimage.ThemirrorreflectstheimagefromtheCRTandtheoscillationofthemirrorcreatesa3Deffect.Asthemirrormovesbackandforththeimageisreflectedbacktotheviewerwithdepthandcolor.Oneofthemajorissueswiththesedisplaysiscreatingamirrorwithhighopticalqualitythatcanbeoscillatedathighfrequencies.Anothermajordisadvantageisthelowqualityofresolutionsoftheimagesbeingdisplayed（4）.

Anotherwaytocreateavolumetricdisplayisthroughtheuseofanobjecttosweepout,orspininsideof,athree-dimensionalvolume.Thisisreferredtoasaspatialdisplay.Theobjectissomeflatpieceofmaterialandisusuallyinarectangularshape.Theobjectisthencoveredwithlightemittingdiodes（LED）.Itcanalsobescannedbyanexternallightsourcetocreatetheimage.Theobjectisplaceverticalontoarodthatisconnectedtoamotor,whichisusedtospintherectangularobject.AstheobjectspinstheLEDlightsareilluminatedtocreateanimage.Theimagehasallthree-dimensionalcues.Thesetypesofdisplayswillalwayshavethedisadvantageofmechanicalmovingpartsthatcanbreakdown,overheat,oraffectingtheabilitytoproduceahighqualityimage（4）.

Volumetricdisplayscanalsobecreatedbyusingasubstancetofillavolume.Thesubstanceisagitatedwithanexternallightsource,suchasalaser,untilitemitslight.Theidealmaterialhasnotyetbeendiscovered.Thematerialneedstohaveexcellentopticalquality,becostefficient,andbelightweight,forthistypeofvolumetricdisplaytoseeanytypeofwidespreaduse（7）.

Allofthesedisplaysshareseveralattributes.Theyhavetheabilitytobeviewedfromallanglesbymultiplepeople.Apersoncouldactuallywalkallthewayaroundthedisplayandviewallsidesoftheimagebeingdisplayed.Thedistancefromwhichtheimagecanbeviewedfromiswideandisonlylimitedbytheaccommodationoftheviewer.Becausethesedisplayscannotproducethecolorsofatruephotoqualityimagestheapplicationsinwhichthesedisplayscanbeusedislimitedandwillbediscussedlater（4）.

Thesedisplayshaveobviousdisadvantages.Allofthese