《物联网专业英语教程》课件第5章

Unit5Barcode[77]

TextA

Barcode[86]

TextB

How2DBarCodeswillWork?[94]参考译文条形码

Abarcodeisanopticalmachine-readablerepresentationofdata,whichshowsdataabouttheobjecttowhichitattaches.Originallybarcodesrepresenteddatabyvaryingthewidthsandspacingsofparallellines,andmaybereferredtoaslinearor1Dimensional(1D).Latertheyevolvedintorectangles,dots,hexagonsandothergeometricpatternsin2Dimensions(2D).BarcodeTextAAlthough2Dsystemsuseavarietyofsymbols,theyaregenerallyreferredtoasbarcodesaswell.Barcodesoriginallywerescannedbyspecialopticalscannerscalledbarcodereaders;later,scannersandinterpretivesoftwarebecameavailableondevicesincludingdesktopprintersandsmartphones.Figure5.1AUPC-Abarcodesymbol

Thefirstuseofbarcodeswastolabelrailroadcars,buttheywerenotcommerciallysuccessfuluntiltheywereusedtoautomatesupermarketcheckoutsystems,ataskforwhichtheyhavebecomealmostuniversal(SeeFigure5.1).TheirusehasspreadtomanyothertasksthataregenericallyreferredtoasAutomaticIdentificationandDataCapture(AIDC).TheveryfirstscanningofthenowubiquitousUniversalProductCode(UPC)barcodewasonapackofWrigleyCompanychewingguminJune1974.

OthersystemshavemadeinroadsintheAIDCmarket,butthesimplicity,universalityandlowcostofbarcodeshaslimitedtheroleoftheseothersystemsuntilthefirstdecadeofthe21stcentury,over40yearsaftertheintroductionofthecommercialbarcode,cametheintroductionoftechnologiessuchasRadioFrequencyIDentification(RFID).

1.Use

BarcodessuchastheUPChavebecomeaubiquitouselementofmoderncivilization,asevidencedbytheirenthusiasticadoptionbystoresaroundtheworld;almosteveryitemotherthanfreshproducefromagrocerystore,departmentstore,andmassmerchandiserhasaUPCbarcodeonit.Thishelpstrackitemsandalsoreducesinstancesofshopliftinginvolvingpricetagswapping,althoughshoplifterscannowprinttheirownbarcodes.Inaddition,retailchainmembershipcards(issuedmostlybygrocerystoresandspecialty"bigbox"retailstoressuchassportingequipment,officesupply,orpetstores)usebarcodestouniquelyidentifyconsumers,allowingforcustomizedmarketingandgreaterunderstandingofindividualconsumershoppingpatterns.Atthepointofsale,shopperscangetproductdiscountsorspecialmarketingoffersthroughtheaddressorE-mailaddressprovidedatregistration.

Barcodescanallowfortheorganizationoflargeamountsofdata.Theyarewidelyusedinthehealthcareandhospitalsettings,rangingfrompatientidentification(toaccesspatientdata,includingmedicalhistory,drugallergies,etc.)tomedicationmanagement.Theyarealsousedtofacilitatetheseparationandindexingofdocumentsthathavebeenimagedinbatchscanningapplications,tracktheorganizationofspeciesinbiology,andintegratewithin-motioncheckweigherstoidentifytheitembeingweighedinaconveyorlinefordatacollection.

Theycanalsobeusedtokeeptrackofobjectsandpeople;theyareusedtokeeptrackofrentalcars,airlineluggage,nuclearwaste,registeredmail,expressmailandparcels.Barcodedticketsallowtheholdertoentersportsarenas,cinemas,theatres,fairgrounds,andtransportation,andareusedtorecordthearrivalanddepartureofvehiclesfromrentalfacilitiesetc.Thiscanallowproprietorstoidentifyduplicateorfraudulentticketsmoreeasily.Barcodesarewidelyusedinshopfloorcontrolapplicationssoftwarewhereemployeescanscanworkordersandtrackthetimespentonajob.

Some2Dbarcodesembedahyperlinktoawebpage.Acapablecellphonemightbeusedtoreadthepatternandbrowsethelinkedwebsite,whichcanhelpashopperfindthebestpriceforaniteminthevicinity.Since2005,airlinesuseanIATA-standard2Dbarcodeonboardingpasses,andsince20082Dbarcodessenttomobilephonesenableelectronicboardingpasses.

2.Symbologies

Themappingbetweenmessagesandbarcodesiscalledasymbology.Thespecificationofa

symbologyincludestheencodingofthesingledigits/charactersofthemessageaswellasthestartandstopmarkersintobarsandspace,thesizeofthequietzonerequiredtobebeforeandafterthebarcodeaswellasthecomputationofachecksum.

Linearsymbologiescanbeclassifiedmainlybytwoproperties:

·Continuousvs.discrete:charactersincontinuoussymbologiesusuallyabut,withonecharacterendingwithaspaceandthenextbeginningwithabar,orviceversa.Charactersindiscretesymbologiesbeginandendwithbars;theintercharacterspaceisignored,aslongasitisnotwideenoughtolooklikethecodeends.

·Two-widthvs.many-width:barsandspacesintwo-widthsymbologiesarewideornarrow;theexactwidthofawidebarhasnosignificanceaslongasthesymbologyrequirementsforwidebarsareadheredto(usuallytwotothreetimeswiderthananarrowbar).Barsandspacesinmany-widthsymbologiesareallmultiplesofabasicwidthcalledthemodule;mostsuchcodesusefourwidthsof1,2,3and4modules.

Somesymbologiesuseinterleaving.Thefirstcharacterisencodedusingblackbarsofvaryingwidth.Thesecondcharacteristhenencodedbyvaryingthewidthofthewhitespacesbetweenthesebars.Thuscharactersareencodedinpairsoverthesamesectionofthebarcode.

Themostcommonamongthemany2Dsymbologiesarematrixcodes,whichfeaturesquareordot-shapedmodulesarrangedonagridpattern.2Dsymbologiesalsocomeincircularandotherpatternsandmayemploysteganography,hidingmoduleswithinanimage.

Linearsymbologiesareoptimizedforlaserscanners,whichsweepalightbeamacrossthebarcodeinastraightline,readingasliceofthebarcodelight-darkpatterns.Stackedsymbologiesarealsooptimizedforlaserscanning,withthelasermakingmultiplepassesacrossthebarcode.

Inthe1990sdevelopmentofChargeCoupledDevice(CCD)imagerstoreadbarcodeswaspioneeredbyWelchAllyn.Imagingdoesnotrequiremovingparts,asalaserscannerdoes.In2007,linearimaginghadbeguntosupplantlaserscanningasthepreferredscanengineforitsperformanceanddurability.

2Dsymbologiescannotbereadbyalaserasthereistypicallynosweeppatternthatcanencompasstheentiresymbol.Theymustbescannedbyanimage-basedscanneremployingaCCDorotherdigitalcamerasensortechnology.

3.Scanners(barcodereaders)

Theearliest,andstillthecheapest,barcodescannersarebuiltfromafixedlightandasinglephotosensorthatismanually"scrubbed"acrossthebarcode.

Barcodescannerscanbeclassifiedintothreecategoriesbasedontheirconnectiontothecomputer.TheoldertypeistheRS-232barcodescanner.Thistyperequiresspecialprogramming

fortransferringtheinputdatatotheapplicationprogram.

"Keyboardinterfacescanners"connecttoacomputerusingaPS/2orATkeyboard-compatibleadaptorcable.Thebarcode'sdataissenttothecomputerasifithadbeentypedonthekeyboard.

Likethekeyboardinterfacescanner,USBscannersareeasytoinstallanddonotneedcustomcodefortransferringinputdatatotheapplicationprogram.

4.Benefits

Inpoint-of-salemanagement,barcodesystemscanprovidedetailedup-to-dateinformationonthebusiness,acceleratingdecisionsandwithmoreconfidence.Forexample:

·Fast-sellingitemscanbeidentifiedquicklyandautomaticallyreordered.

·Slow-sellingitemscanbeidentified,preventinginventorybuild-up.

·Theeffectsofmerchandisingchangescanbemonitored,allowingfast-moving,moreprofitableitemstooccupythebestspace.

·Historicaldatacanbeusedtopredictseasonalfluctuationsveryaccurately.

·Itemsmayberepricedontheshelftoreflectbothsalepricesandpriceincreases.

·Thistechnologyalsoenablestheprofilingofindividualconsumers,typicallythroughavoluntaryregistrationofdiscountcards.Whilepitchedasabenefittotheconsumer,thispracticeisconsideredtobepotentiallydangerousbyprivacyadvocates.

Besidessalesandinventorytracking,barcodesareveryusefulinlogistics.

·Whenamanufacturerpacksaboxforshipment,aUniqueIdentifyingNumber(UID)canbeassignedtothebox.

·AdatabasecanlinktheUIDtorelevantinformationaboutthebox;suchasordernumber,itemspacked,quantitypacked,destination,etc.

·TheinformationcanbetransmittedthroughacommunicationsystemsuchasElectronicDataInterchange(EDI)sotheretailerhastheinformationaboutashipmentbeforeitarrives.

·ShipmentsthataresenttoaDistributionCenter(DC)aretrackedbeforeforwarding.Whentheshipmentreachesitsfinaldestination,theUIDgetsscanned,sothestoreknowstheshipment'ssource,contents,andcost.

Barcodescannersarerelativelylowcostandextremelyaccuratecomparedtokey-entry,withonlyabout1substitutionerrorin15,000to36trillioncharactersentered.Theexacterrorratedependsonthetypeofbarcode.

1.IntroductiontoHow2DBarCodesWork

Inthesummerof1974atagrocerystoreinTroy,Ohio,aneventfirsttookplacethatwouldforeverchangethewaywepurchasethings:AclerkscannedtheUPCcodeonapackofWrigley'sgum.How2DBarCodeswillWork?TextBUPCcodesexplodedinpopularityafterhittingthemarket,andtodayyoucanfindthemonpracticallyeveryproductontheshelves.Likeallbarcodes,UPCcodesbridgedthephysicalanddigitalworlds,providinganyonewithabarcodescannerinstantaneousaccesstothedatathatabarcodecontains.

Likeallofthefirstbarcodeformats,UPCcodeswere1D,meaningtheyonlycarriedinformationinonedirection.One-dimensionalcodesworkedfineforcarryingsmallamountsofdatalikenumericproductcodes,butasthedigitalworldbecamemorecomplex,theneedforabarcodecapableofcarryingmoredatabecameapparent.

Onesolutionstillusedtodayisthestackedbarcode,which,asthenameimplies,containsanumberof1Dcodespiledoneontopofanother.Althoughstackedbarcodescanaccommodatemoreinformationthantheirtraditional1Dcounterparts,theycanquicklygrowverylargeinordertostoremoredataandcanbedifficulttoread.Inordertohaveabarcodethatwassmallinsize,easytoreadandcapableofholdingbothalargeamountofdataandalargevarietyofcharactertypes,themarketcalledforanewapproach.Enter2Dbarcodes.(SeeFigure5.2)

2Dbarcodescanholdmountainsofinformation,

comparedtotheirlow-tech1Dpredecessors.

Figure5.22Dbarcodes

Asyoumighthaveguessed,2Dbarcodes(sometimescalledmatrixcodes)carryinformationintwodirections:verticallyandhorizontally.Accordingly,2Dbarcodesarecapableofholdingtensandevenhundredsoftimesasmuchinformationas1Dbarcodes.Forinstance,oneofthemostpopular2Dbarcodeformats,DensoWave'sQRCode,canholdmorethan7,000digitsor4,000charactersoftext,whereaseventhemostcomplex1Dcodestopoutaround20characters.2Dbarcodesarealsosmallandeasytoscan.

Still,2Dcodesaren'tperfectforeveryapplication.Becausethey'remorecomplexthan1Dcodes,theyrequiremorepowerfulscannerstodecode.What'smore,manypeoplearesimplyunfamiliarwiththetechnology,whichhinderswidespreadadoption.Butthankstothesmartphoneinyourpocket,thatmayallbeabouttochange.Readontofindoutwhy.

2.2DBarCodeGeneratorsandScanners

WhenthenowubiquitousUPCcodefirststartedmakingwavesinthe1970s,retailerseverywhererecognizedthepotentialimmediately.Unfortunately,thetechnologyfacedsomethingofaCatch-22.RetailersrefusedtobuytheexpensivescannersneededtoreadthecodesuntilmanufacturersbeganputtingUPCcodesonalloftheirproducts,andmanufacturersstonewalledonadoptingthemuntiltheyknewretailerscouldreadthecodes.Eventually,largeretailerslikeKmartjumpedintokick-startthetechnology.

Fortunatelyforproponentsof2Dbarcodes,webuymillionsofscannerseveryyearintheformofoursmartphones.CommonmodelsliketheiPhone,BlackBerryandAndroidallhavethecapabilitytoreadthemostpopular2Dbarcodeformats,helpingtoclearperhapsthelargesthurdletotheirwidespreadadoption.Buthowdoesasmartphone—oranybarcodescanner,forthatmatter—actuallymakesenseoftheseeminglyunintelligiblepatternsoflinesandsquaresthat2Dbarcodescontain?Partoftheanswerliesinthedesignofthebarcodeitself,whichiscreatedfromthegrounduptomakethescanningprocessasaccurateandspeedyaspossible.

Let'scheckoutofoneofthemostwidespreadtypesof2Dbarcodes,QRCodes,toseehowitsdesignhelpsbarcodescannersreadthedataitcontains.Forstarters,everyQRCodecontainsafinderpattern,anarrangementofsquaresthathelpthescannerdetectthesizeoftheQRCode,thedirectionit'sfacingandeventheangleatwhichthecodeisbeingscanned.Next,everyQRCodecontainsanalignmentpattern,anotherpatternofsquaresdevisedtohelpscannersdetermineifthe2Dbarcodeisdistorted(perhapsit'splacedonaroundsurface,forinstance).QRCodesalsohavemarginsforerror,meaningthatevenifpartofthecodeissmudgedorobscured,thecodecanoftenstillbescanned.

Butevenaperfectlydesignedbarcodewouldbenothingwithoutsophisticatedsoftwarecapableofrecognizingthebarcode'salignmentpatternsanddecodingthedata(SeeFigure5.3).Forinstance,thescanningsoftwareusedtoreadQRCodeshassomeprettyimpressivecapabilities.Oncethesmartphone'scameraprocessesthecode'simage,thesoftwaregoestoworkanalyzingtheimage.Bycalculatingtheratiobetweentheblackandwhiteareasofthecode,itcanquicklyidentifywhichsquaresarepartofthealignmentpatternsandwhichsquarescontainactualdata.UsingtheQRCode'sbuilt-inpatternsanderrorcorrection,thesoftwarecanalsocompensateforanydistortionorobscuredareasofthebarcode.Afterthesoftwarehasdigitally"reconstructed"theQRCode,itexaminesthejumbleofblackandwhitesquaresintheQRCode'sdatasectionandoutputsthedatacontainedwithin.

Ofcourse,QRCodeisonlyoneexampleofa2Dbarcode.Forinstance,theshipping

companyUPSusesaformatcalledMaxiCode,whichcanbescannedveryquicklyaspackagesflydowntheconveyorbelt,whereastheU.S.DepartmentofDefensehasadoptedDataMatrix,a2Dbarcodeformatcapableofholdingalotofinformationinaverysmallarea.Regardlessoftheformat,2Dbarcodescontainbothdataandbuilt-inpatternstohelpthescannerdecodetheinformationeachbarcodecontains,andinmanycases,onedevicecanreadavarietyofdifferentformats,eventraditional1Dbarcodes.

Figure5.3Diagramofa2Dbarcode

Ifyouwanttocreateyourown,you'llfindseveralgreat2Dbarcodegeneratorsonline.Theyletyouadjusteverythingfromtheformatyouwanttousetothesizeofthecode,sothenexttimeyou'reputtingupaflyerforyourlocalgaragesale,consideraddinga2Dbarcodewithyourhomeaddressatthebottom.Whoknowshowmanysmartphone-carryingbargainhuntersyoumightattract?

3．2DBarCodeAdvertising

Ifyoucanthinkofawaytosellaproduct,it'sprobablybeendone:blimpswithgiantcompanylogos,televisionsstreamingadstothebackseatsoftaxicabsandevenadvertisementsprintedinedibleinkonfood.Nothingisoff-limitsfromadvertisers.Buteventheyhavelongfacedadifficultchallengeastheytrytodeterminehoweffectivetheirphysicaladsreallyare;regardlessofthemedium,theycanonlyguesshowmanypeopleendupbuyingproductsorlearningmoreabouttheircompanybecauseofaparticularad.Thatallchangedwith2Dbarcodes.Forthefirsttime,companiescouldsimplyadda2Dbarcodetotheiradvertisementanddirectlytrackhowmanytimesconsumersscannedthecode.Ifsomeonedidscanit,theadvertiserscouldthentrackwhetherthatpersonwentontovisitthecompany'sWebsiteorevenpurchaseaparticularproduct.

Puttingthetechnologytouse,thefashioncompanyTommyBahamaaddeda2DbarcodeintoEsquireMagazinethat,whenscanned,tookreadersdirectlytoaWebpagefeaturingthepairofsunglassesshowninthemagazinead.Withoneclickoftheirmouse(orsmartphone),readerscouldthenbuythesunglassesforacool$138apop.NotonlydidthecodeshelpTommyBahamasellalotofsunglasses,theyalsohelpedthecompanylearnmoreabouttheircustomers,tellingthecompanywhattimeofdayandpartofthecountryanadwasscanned.

Targetisanothercompanyexploringthecapabilitiesof2Dbarcodes,addingQRcodestoitsmagazineadvertisements.Curiousreaderscanscanthecodesandinstantlywatchavideofromafamousinteriordesignerexplaininghowtousetheproductinthehome.Advertiserssaythislevelofinteractivityisperfectforanewgenerationoftech-savvyconsumerswhowantinstantaneousaccesstoproductinformation,reviewsandmore.Infact,thecodeshavebecomesuchapopularwaytoadvertiseinJapanthatthey'reevenfoundonbillboards,wheretheycanbescannedathighwayspeedsfromapassingcar.

Currently,thecodesaren'taspopularintheUnitedStatesastheyareinJapan,sodataonjusthowmanyadvertisersareusingthemandwhatsortofresultsthey'vebeengettingishardtocomeby.Still,asmorepeoplepurchasesmartphonesandlearnaboutthecapabilitiesofQRCodes,2Dbarcodesmaytakeoffmuchliketheir1Dpredecessors.

条形码是光学仪器可以阅读的数据表现形式，可以用来表示附带它的物体的数据。起初，条形码通过改变平行线的宽度和间距来表示数据，也被称为线性或一维条形码(1D)。后来其发展为矩形、圆点、六边形和其他几何形状的二维条形码(2D)。条形码参考译文虽然2D系统使用了多种符号，但仍然被称为条形码。原来，用叫做“条形码阅读器”的专用光学扫描仪来扫描条形码；后来，将扫描仪和解释软件用在了包括桌面打印机和智能手机的设备上。

条形码最早用于有轨电车的车票上，但没有取得商业上的成功，直到它们被用于自动化超市结账系统才成功，且条形码在该系统中的应用已经非常普遍。条形码(如图5.1所示)也被广泛应用于许多其他涉及自动识别和数据捕捉(AIDC)的任务。现在无处不在的通用产品代码(UPC)最早是在1974年6月用于Wrigley公司的口香糖包装上。虽然后来其他系统也进入了AIDC市场，但是条形码的简单性、广泛性和低成本限制了这些系统。直到21世纪最初的10年，在条形码引入商业领域40年之后，像无线射频识别(RFID)这样的技术才进入商业领域。

1.应用

如UPC这样的条形码已经成为现代文明社会无所不在的元素，全世界的商店都热衷于使用它。除生鲜外，杂货店、百货公司及超级市场中几乎全部商品都使用UPC条形码。这可以用来跟踪商品和防盗(包括换定价标签)，虽然扒手现在也可以打印自己的条形码。另外，零售链会员卡(主要由杂货店和如运动器材、办公品和宠物店这样特定“大包”的零售店发行)也使用条形码来唯一地识别客户，这样可以了解到消费市场及客户的个人消费模式。在购物点，通过登记的地址和电子邮件地址，购货人可以得到折扣和特价优惠。通