Představení typu
Ruční skenovací pistole
Thehandheldscanninggunisaproductformedbytechnologylaunchedin1987.ItlooksverysimilarThesupermarketcashieristhesameasthebarcodescannerusedinhishand.ThemajorityofhandheldscannersuseCIStechnology,withanopticalresolutionof200dpi,andtherearemultipletypesofblackandwhite,grayscale,andcolor.Thecolortypeisgenerally18-bitcolor.Therearealsoafewhigh-endproductsthatuseCCDasaphotosensitivedevice,whichcanachievetruecolorwithbetterscanningeffect.
Smalldrumscanner
Thisisanintermediateproductofhandheldscannersanddesktopscanners(newemergenceinrecentyears,becauseitisThebuilt-inpowersupplyandsmallsizearecallednotebookscanners.MostoftheseproductsuseCIStechnology,withanopticalresolutionof300dpi,andtwotypesofcolorandgrayscale.Thecolormodelisgenerally24-bitcolor.TherearealsoafewsmalldrumscanninggunsthatuseCCDtechnology,andthescanningeffectissignificantlybetterthanthatofCIStechnologyproducts,butduetostructurallimitations,thevolumeisgenerallysignificantlylargerthanthatofCIStechnologyproducts.
Thesmallrollerdesignistofixthelensofthescanninggun,andmovetheobjecttobescannedtoscanthroughthelens.Itoperateslikeaprinter.Theobjecttobescannedmustpassthroughthemachinebeforebeingsentout.,Thescannedobjectcannotbetoothick.Thebiggestadvantageofthisscanninggunisthatitisverysmall,butduetoitslimitations,forexample,itcanonlyscanthinpaper,andtherangecannotexceedthesizeofthescanninggun.
Platformscanner
Alsoknownasflatbedscanneranddesktopscanner,mostofthescannersonthemarketareflatbedscanners.Gunsarenowthemainstream.Theopticalresolutionofthistypeofscanninggunisbetween300dpi-8000dpi,thecolordigitsrangefrom24-bitto48-bit,andthescanningformatisgenerallyA4orA3.
Theadvantageoftheflatbedtypeisthatlikeusingacopier,aslongastheuppercoverofthescanninggunisopened,nomatterbooks,newspapers,magazines,photonegativescanbeputonandscanned,itisquiteconvenient,andthescannedeffectItisalsothebestamongallcommontypesofscanningguns.
Ostatní
Ostatníincludelarge-formatscanningguns,pen-typescanningguns,barcodescanningguns,filmscanningguns(noteItisnotaflatbedscanninggunplusapenetratingscan,theeffectismuchbetter,andthepriceisofcoursealsoexpensive),physicalscanningguns(notflatbedscanninggunswithphysicalscanningcapabilities,similartodigitalcameras),andmainlyusedinthefieldofprintingandtypesettingRollerscanninggunsandsoonaremany.
Typ rozhraní
SCSI rozhraní
SCSI rozhraníisastandardinterfaceforsmallcomputers.
Themaximumnumberofconnecteddevicesforthisinterfaceis8.Usuallythemaximumtransmissionspeedis40M/S,whichisfaster,andgenerallyconnectstohigh-speeddevices.TheinstallationofSCSIdevicesismorecomplicated,andaSCSIcardisusuallyaddedtothePC,whichispronetohardwareconflicts,butithaspowerfulfunctions.
Rozhraní EPP
Rozhraní EPPisanenhancedparallelinterface.
Anenhancedtwo-wayparalleltransmissioninterfacewithamaximumtransmissionspeedof1.5Mbps.TheadvantageisthatthereisnoneedtouseothercardsinthePC,thenumberofconnectionsisunlimited(aslongasyouhaveenoughports),andthedeviceiseasytoinstallanduse.ThedisadvantageisthatthespeedisslowerthanSCSI.Thisinterfaceissimpleandconvenienttoinstallanduse,andreplacetheSCSI rozhraníinthelow-endandlow-endoccasionswhereperformanceisnothigh.
USB rozhraní
USB rozhraníistheuniversalserialbusinterface.
Upto127peripheralscanbeconnected.ThemaximumtransmissionspeedoftheUSB1.1standardis12Mbps,andthereisanauxiliarychanneltotransmitlow-speeddata.Inthefuture,ifthereisaUSB2.0standardscannerspeed,itmaybeexpandedto480M/s.Withhotplugfunction,plugandplay.ThescanninggunofthisinterfaceisgraduallypopularizedwiththeestablishmentandpromotionoftheUSBstandardunderthepushofIntel.
Bezdrátové rozhraní
TheBluetoothbarcodescannerdoesnotneedtobechargedwithinacertainrange!
Pracovní princip
Commonflatbedscanninggunsaregenerallycomposedoflightsource,opticallens,scanningmodule,analog-digitalconversioncircuitandplasticshell.Itusesphotoelectricelementstoconvertthedetectedlightsignalintoanelectricalsignal,andthenconvertstheelectricalsignalintoadigitalsignalthroughananalog-digitalconverterandtransmitsittothecomputerforprocessing.Whenscanninganimage,thelightsourceshinesontheimageandthereflectedlightpassesthroughthelenstoconvergeonthescanningmodule.Thescanningmoduleconvertsthelightsignalintoananalogdigitalsignal(ievoltage,whichisrelatedtotheintensityofthereceivedlight).Related),andatthesametimepointoutthedegreeofdarknessoftheimagenumber.
Atthistime,theanalog-digitalconversioncircuitconvertstheanalogvoltageintoadigitalsignalandsendsittothecomputer.Thecolorisquantizedwith8,10,and12bitsoftheRGBthreecolors,andthesignalisprocessedintotheimageoutputoftheabove-mentionednumberofbits.Ifthereisahighernumberofquantizationbits,itmeansthattheimagecanhavericherlevelsanddepth,butthecolorrangehasexceededtherecognitionabilityofthehumaneye,soforus,ahighernumberofscanninggunsarewithinthedistinguishablerange.Theeffectofscanningisthatthecolorsaresmoothlyconnected,andmoredetailsofthepicturecanbeseen.
Rozlišení
Theresolutionofthescanninggunshouldbedeterminedfromthreeaspects:theopticalpart,thehardwarepartandthesoftwarepart.Inotherwords,theresolutionofthescanninggunisequaltotheresolutionofitsopticalcomponentsplusitsownresolutionobtainedbyprocessingandanalyzinghardwareandsoftware.
Opticalresolutionistheactualnumberoflightpointsthatcanbecapturedbytheopticalcomponentsofthescanninggunpersquareinch.ItreferstothephysicalresolutionofthescanninggunCCD(orotheroptoelectronicdevices),whichisalsothescanningTherealresolutionofthegun,itsvalueisthevalueobtainedbydividingthepixelpointsthatthephotoelectricelementcancapturebythemaximumscannablesizeofthescanninggun.Forexample,ascanninggunwitharesolutionof1200DPIoftenonlyaccountsfor400-600DPIintheresolutionoftheopticalpart.Theresolutionoftheextendedpartisjointlygeneratedbyhardwareandsoftware.Thisprocessisgeneratedbyanalyzingtheimagethroughacomputerandmathematicallyfillingtheblankpart(thisprocessisalsocalledinterpolationprocessing).
Opticalscanningandoutputareone-to-one,andwhatisscannediswhattheoutputis.Afterthecomputersoftwareandhardwareareprocessed,theoutputimagewillbecomemorerealisticandtheresolutionwillbehigher.Mostofthescannerssoldonthemarkettodayhavetheabilitytoexpandtheresolutionofsoftwareandhardware.Somescanninggunadvertisementswrite9600×9600DPI,whichisonlythemaximumresolutionobtainedthroughsoftwareinterpolation,nottherealopticalresolutionofthescanninggun.Soforthescanninggun,itsresolutionhasopticalresolution(oropticalresolution)andmaximumresolution.Ofcourse,whatwecareaboutisopticalresolution,whichishardwork.Wesaythattheresolutionofascanninggunisashighas4800DPI(this4800DPIisthesumoftheopticalresolutionandsoftwaredifferenceprocessing),whichmeansthatwhenthescanninggunisusedtoinputtheimage,itcancollect4800×onthescanningareaof1squareinch.4800pixels(Pixel).Thescanningareaof1inchsquare,theimagesizegeneratedafterscanningwiththeresolutionof4800DPIis4800Pixel×4800Pixel.Whenscanninganimage,thehigherthescanningresolutionisset,thefinertheeffectofthegeneratedimageandthelargerthegeneratedimagefile,butthemoreinterpolatedcomponents.
Optoelektronická zařízení
CCD
ThemainstreamistwokindsofCCD,theprincipleissimply:integratedonasiliconsinglecrystalTherearethousandstotensofthousandsofphototransistors,thesephototransistorsaredividedintothreerows,respectivelycoveredwithred,greenandbluecolorfilters,soastoachievecolorscanning.ComparingthetwoCCDs,thesiliconoxideisolationCCDisbetterthanthesemiconductorisolationCCD.Friendswhoarefamiliarwithphysicsnaturallyknowthereason.Simplyput,theleakagephenomenonbetweenthesemiconductorCCDtransistorswillaffectthescanningaccuracy.Theisolationwithsiliconoxidewillgreatlyreducetheleakagephenomenon(thisisaninsulator).Ofcourse,itisbesttoaddtemperaturecontrol,becausewhetheritisasemiconductororaconductor.Theyarealltemperature-sensitive,andtheconductivitywillgenerallyincreasewhenthetemperaturerises(thecostwillincreasealot,theprice,letaloneeveryoneknowswhatwillhappen).Nowadays,mostofthemainstreammarketisforsemiconductor-isolatedCCD,whilethesilicon-oxide-isolatedCCDisrelativelysmall,obviouslybecauseofthehighercost.Ifyouwanttounderstandtheeffectofascanninggun,itisveryimportanttounderstandwhatqualityphotoelectriccomponentsthescanninggunuses.Haha,eventhesamesemiconductorisolationqualityisdifferent.
Kontaktujte fotocitlivé zařízení
Thephotosensitivematerialusedinthecontactphotosensitivedeviceisgenerallycadmiumsulfide,whichisusedtomakephotosensitiveresistors.TheproductioncostshouldbeItismuchlowerthanCCD(thesameprecisionCISscanneronthemarketisalwayscheaperthanCCDscannerforthisreason).Thescanningdistanceisshort,thescanningresolutionislow,orsometimesitcannotreachthenominalvalue,andthetemperaturechangeiseasiertoaffectthescanningaccuracy.Thesearethefatalproblemsofthisscanninggun.Friendswhoarefamiliarwithphysicsshouldknowthattheleakageofcadmiumsulfidebetweenresistorsislargerthanthatofsemiconductorbarriers,whichwillreducetheaccuracy(hehe,letalone,CISseemstobeterriblybad,themanufacturerofthescanninggunwillcomeandkillMe).
Fotonásobič
Fotonásobič,thephotosensitivematerialismainlytheoxideofmetalcesium.Hisscanningaccuracy,eventhedegreeofinfluencebytemperatureandnoisearethebest,butthepriceisalsothemostexpensive.Generaluserslikemearejustdreamingofit.Thepriceistooexpensiveandwewillignoreitsspecifictechnicalfeatureshere.
jiný
Theoptoelectronicdeviceofascanninggunisanimportantfactorindeterminingitsperformance,andotherthingssuchascontrolcircuitsandsoftwarearealsoveryimportant.Itmaybedifficulttounderstandthesematerialsdirectly.Wecanoftenonlyunderstandlimitedcontent(tradesecrets).Whenwedetecttheperformanceofascanner,wecanonlyunderstanditbymeansofactualoperationandevaluationsoftware.
Cenový rozdíl
One-dimensionalbarcodescanninggunsaremainlydividedintoredlightCCDscanning(redstripsduringscanning)andlaserscanning(redlightscanning),
Thetwo-dimensionalcodescannermainlyusestheimage-baseddecodingmethod(thegeneralscanningheadcanseethecrystalsimilartothecamera),
Sohowtodistinguishthepricefactorofeachtypeofscanner,themostThemainreasonliesinthescanningaccuracyofthescanner.Forexample,thesmallerthebarcodethatcanbescannedbyaone-dimensionalscanner,thefasterthescanningspeed,andthehighertheprice;thesameistruefortwo-dimensionalscanners.Thismethodofjudgment.
Ostatnípecialfunctionswillalsoincreasethepriceofthescanner,suchasscanningDPMcodes(laserengravingcodes),orscanningfarawaybarcodes.
Moreover,thepriceofscannersisgenerallydeclining,andtherearealsofreemobilephonesintheworldtoscanbarcodesandsendthemtocomputers,sothatthemobilephonescanbeusedasbarcodescanners,soifthebarcodescannerdoesnotrequirespecialscanningcapabilities,Thepricehasdroppedalot.