he still remembers the rest of the route correctly. The man is wearing a baseball hat. There is a small camera in the screen of the h at, looking downwards at his.
In: H.-J.Bullinger,J.Ziegler,(Eds.). Human-Computer Interaction: th Ergonomics and User Interfaces Proc. . HCIInternational’99(the8 InternationalConferenceoH n uman-Computer Interact ion),Munich, Germany,August22-26,1999,Vol. 1.Mahwah,NJ&L ondon: LawrenceErlbaumAssoc.pp. 531-535.
VirtualTactileMaps JochenSchneiderandThomas Strothotte Otto-von-GuerickeUniversity oMagdeburg f
1 Introduction Tactilemapsconstitutethemediamostcommonlyuse dbyblindandpartially sightedpeoplefortheexplorationospatial f infor mation.However,comparedto mapsforsightedpeople,theyareinconvenient top roduceandcontainlessinformation.Wehavedevelopedmethodsandimplemente dthemprototypically, bywhichvisuallyimpairedpeoplecanexploregeo a graphicalareaflexiblywith thehelpoacomputer f through virtualtactilemaps The . designoasystem f is presentedwhichcaptureshandpositionsthroughav ideocameraandproduces acousticoutput.Itusesdigitalmapdatawhichis adaptedtotherequirementsof theusers.Oneothe f mostcompellingproblem isho w todealwiththescaleoaf map,inparticularthenon-linearityom f aps.Inth ispaper,thedevelopmentof theprototypeandinitialexperiencewith iare t pr esented.
2 AChallengingVision Aman,recognizablebythelongwhitecanehanging blind,isstandingonasidewalk.Heisholdinghis movingthemwithconcentration.Heiisnthemiddle walkthroughthedowntownareawiththehelpoaf exploredtheareaandchosenroute a throughiat t hestillrememberstherestoftheroutecorrectly. hat.Thereismall as camerainthescreenothe fh handsandpickinguptheirpositions.Thecamerais puter,whichemitsinformationthroughsmallearpho
Thescenariodescribedisavision.Wereportonth fortheexplorationofvirtualtactilemapsasawe 1997).Inthispaper,theconceptofvirtualtactil implementationwillbepresented.
fromhisarmasbeing handsinfrontofhimand ofplanningtherestofhis virtualtactilemap.Hehad home.Nowheicsheckingif Themaniw s earing baseball a at,lookingdownwardsahis t connectedtoasmallcomnes.
edevelopmentofasystem arablecomputer(cf.Mann emapsandaprototypical
3 TheVirtualTactileMapConcept Virtualtactilemapsystemsaredigitalmapsystems soundwhentheirmapsareexploredbyhandmovement enableblindandpartiallysighteduserstoexplore spaceandlearnroutesinit,similartotactilema andnamedafter.Thefirstaspectoftheuserinter istheinterpretationofhandgesturesandtheirma space;thesecondaspecttheselectionandacoustic geographicalelementsonthemap;thethirdaspect mapdatatrepresentation oa suitablefor handinpu Virtualtactilemapsservetoaidorientation,defi ing/knowingthespatialrelationsbetweenthetrave directionobody f andsignificantfeaturesospace f mapsbelongtoacertainkindoeflectronictravel temsfor larger space.
whichemitspeechand s.Virtualtactilemaps anunknowngeographical ps,whichtheyareinspiredby actionwithvirtualtactilemaps ppingtothegeographical alpresentationofthe thepreparationothe f digital t,which irelatively s coarse. nedbyJanssonas“perceivler’scurrentpositionand ”(Jansson 99). Virtualtactile aids,namelyorientationsys-
4 RelatedWork The“KnowWhere”systemishand a gesturerecognitio geographicalinformationtoblindpeople(Krueger& presentszoomablegeographicalobjects(e.g.,outli asoundwhenthehandsoauser f touchtheirimagin Thehandslieontactile a grid.Theirmovementsle inaccordancetothekindothe f geographicaleleme KruegerandGildenhaveconductedtest a oftheirs blindsubjects.Thetestconsistedofexploringlar subjectswereabletofindeasilyabsoluteposition oftheshapesexploredafterwards.Twowerealsoab drawings of theoutlines of thegeographicalobject
nsystemwhichconveys Gilden1997).Thesystem nesocountries) f byemitting aryimageonthedesktop. adtospeechosound r output ntwhichtheyhavetouched. ystemwithfivecongenitally gegeographicobjects.The asndrecognizepuzzlepieces letoproduce“acceptable” s.
Althoughtheybothdealwithpresentinggeographica groupthroughvideogestureinputandacousticalou virtualtactilemapsdifferinsomeimportantaspec KnowWhereconsistsoaflighttableandspecial-pur cilitatesthegesturerecognition,butalsoimpedes spreaduseofthesystem.Evenmoreimportant,virt convey information oan furbanarea,as street a ma conveys large-scalegeographicalinformation,as an
objects l tothesameuser tput,K nowWhereand ts.Thehardwareusedfor posehardware,whichfaportabilityandthewideualtactilemapsserveto pdoes,whereasKnowWhere atlas does.
Starner,WeaverandPentland(1998)describeawear recognizesAmericanSignLanguagegesturesthrough isbeingdevelopedtoeventuallytranslatethegest
ablecomputer,which videoinput.Thesystem uresintospokenlanguage.A
cameraincap a theuseriswearingwhichlooksdow gestures.Thisapproachshowsthefeasibilityoth f implementing virtualtactilemaps.
nahis t handspicksupthe ve isionoaw f earablesystem
5 TheDesignofaVirtualTactileMapSystem Inthissection,requirementsovf irtualtactilema system arepresented. 5.1
Requirements
Requirementsforvirtualtactilemapscanbelicit trianspreparethemselvesforawalkinanurbanar Blindpeoplewhowishtonavigateindependentlyhav oftheareagiven,learnsegmentsopafathandang recognizethemduringwalking(Golledgeeal. t 1996 supportthisprocessbypresentingtheinformation 1996),astudyids escribedinwhichblindpedestri bilitytrainerswereaskedaboutinformationanele throughspeechsynthesis.Informationidentifiedas thetypeofroad,distancesandobstaclesonit;in desirablewasdetailsaboutobjectssuchashops, informationidentifieda“snice-to-have”wasthose as roadworks anddiversions. 5.2
psandthedesignoafnactual
edbayskinghowblindpedeseanotfullyknowntothem. etomemorizethelayout lesbetweenthemandhaveto ).Acomputersystemcan needed.In(Strothotteeal. t ansandorientationandmoctronictravelaidshouldemit essentialwasthenameand formationidentifiedas publicbuildings,etc.Finally, ontemporaryobstaclessuch
System Design
Basedontherequirementsdescribedabove,methods tionofvirtualtactilemapsweredesigned.Thedes prototype,andafirsttestwasconducted.Themost designweretheinteractionandthepreparationof describeditnhefollowing.
andtoolsfortheexploraignwasimplementedasa importantaspectsofthe themapdata,whichwillbe
Interactionwithcartographicobjectsonvirtualta pointing.Apointingdeviceforavirtualtactilem portable,affordable,andallow absolutesettingof arenotactiledisplaysotrouchtabletsavailable ments.Therefore, vaideocameraiused s aan sinpu mapapproachpresentedhere.Thehandmovementsres geographicalobjectsunderthehandandtheirrelat speech andsound.
ctilemapsisdonethrough apsystemhastobelarge, morethanoneposition.There meetingallotfheserequiredevice t forthevirtualtactile ultininformationabout ionto thersbeingemittedas
Thevirtualtactilemapsystem presentedheresuppo learningofaroute.Explorationisdonebymoving
rts both mapexplorationand handsfreelyonthemap,
whichresultsinthesystemspeakinginformationab hands.Routelearningids onebyfirstselectinga afingerontheroutethroughsound.Currently,pit convey thedistanceothe f fingerfrom theroute.
outtheobjectsunderthe route.Thesystemthenguides chandbalanceareusedto
Commerciallyavailablemapdataius sedinthesyst ofstreetcarstops,etc.Thesystemmanagesthema calInformationSystem(GIS),whichiasbletoansw elements at caertain position othe r distancebetw
em,enrichedwithpositions pdatainsmall a Geographierrequestsongeographical een points.
6 ImplementationandTestofaPrototype Therequirementsaboveledtothedesignandimplem Theprototypicalsetupistationary.Thecamerais table.Thestationary setupmakesipossible t tous thecameraiasimedat,whichservesto rientthe processingbyprovidingaconstantbackground.Ina beemployedaisnteractiondevices,e.g.toplacel tipsandmarkersarerecognizedthroughcolorsegme indexfingersbyfindingthecoloroaring f eachf 1).
entationofaprototype. mountedontripod a abovea tactile ae gridpadonthedesk handsandtofacilitateimage ddition,smallmarkerscan andmarksonthemap.Finger ntation,inthecaseotfhe ingertipiw s earing(see Fig.
Aprototypefirstprototypeofavirtualtactilema recognitionfor sainglehandandwithoutmarkersw aboutfortyyears,experiencedinusingtactilemap wholemapandthelearningorafouteweretested. jectmovedhishandonthepad.Whentouchingastr name.Thestreetexplorationmodewastestedaswel roughlydiagonalthroughthemapwasselected.The thestreetwith theindex finger,guidedbtone ay
psystemwithhandgesture astestedbyblind a maleof s.Boththeexplorationothe f Fortheformer,thetestsubeet,thesystememittedits l:Alongstreetrunning subjectthentriedtofollow changing ipnitch andbalance.
Themapexplorationfeaturewasfelttobueseful, certain streetthrough balanceandpitch toorough, tothespeakersused.Also,thegesturerecognition black-and-whitepictures,resulting ijnumps of the
thecodingothe f distancetoa which can partlybaettributed subsystemwasprocessing calculatedhandposition.
7 FutureWork Thegesturerecognition,thepreparationothe f geo ticalcodingstillneedtobreefined.Theextento theuserbyplacingtokensofdifferentformsonth investigatedhowthesetokenscanbreeplacedwhen prototypeimplementedthusfar to truly a mobilesy
graphicaldataanditsacousam f apcanthenbechosenby etable.Irt emainstobe movingfromthestationary stem.
AcousticalOutput Sound Speech
GIS
Image capturing Raw map data Object recognition Fingers Markers Fig. 1: Architecture othe f prototype
8 References Mann,S.(1996).Wearablecomputing:afirststept IEEEComputer 30 ,(2), 25–32. Jansson,G.(1999).Spatialorientationandmobilit Silverstone,B.,Lang,M.A.,Rosenthal,B.&Fraye houseHandbookonVisualImpairmentandRehabilitat LighthouseandOxfordUniversity Press.Forthcoming
owardspersonalimaging. yforthevisuallyimpaired.In E. , E.(Eds.): TheLightion.NewYork:The .
Krueger,M.W.&Gilden,D.(1997).KnowWhere™:an audio/spatialinterface forblindpeople. Proc.ICAD’97 Xerox . PARC:Xerox.(Availableonlineunder http://www.santafe.edu/~kramer/icad/websiteV2.0/Conferences/ICAD97/ Kruger.PDF). Starner,Th.,Weaver,J.&Pentland,A.(1998).Rea guagerecognitionusingdeskandwearablecomputer actions on PatternAnalysis andMachineIntelligenc
l-timeAmericanSignLanbasedvideo.IEEETranse,20(12), 1371-1375.
Golledge,R.G.,Klatzky,R.L.,&Loomis,J.M.(1 996).CognitiveMapping andWayfindingbyAdultsWithoutVision.InPortuga li,J(. Ed.): TheConstructionoCognitive f Maps Dordrecht: . Kluwer,215–246.
