2022年增强现实(AR)技术开发指南(版)_第1页
2022年增强现实(AR)技术开发指南(版)_第2页
2022年增强现实(AR)技术开发指南(版)_第3页
2022年增强现实(AR)技术开发指南(版)_第4页
2022年增强现实(AR)技术开发指南(版)_第5页
已阅读5页,还剩17页未读 继续免费阅读

下载本文档

版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领

文档简介

MobiDev:2022年增强现实(AR)技术开发指

南(pdf版)

MobiDev是一家软件开发公司,致力于增强现实(AR)、

人工智能与机器学习以及物联网等创新技术领域。近日

MobiDev发布了《2022年增强现实(AR)技术开发指南》。报

告探讨了AR技术与移动AR的发展现状,分析了该技术在

2022年进一步发展将面临的障碍并给出了对应策略。

AR技术概述

AR的受众正在增长。研究机构ARtillery

Intelligence报告称,美国成年人对AR功能的移动使用量增加

了29%o这主要是受在iPhone和Android设备的原生ARKit

和ARCore架构上运行的专用AR应用程序所推动。

ARtilleryIntelligence还报告称,与完全基于增强现实的应用程

序相比,应用程序中包含的AR功能的参与度要高得多。

游戏、社交和视觉搜索是AR最受欢迎的消费者使用案

例。PokemonGo在2020年带来了19.2亿美元的收入,且正

在试验Microsoft

Hololens,其最终目标是为更多的观众带来可穿戴游戏体验。

AR技术并不局限于普通消费者,制造商和智能城市是其

瞄准的另一个重要领域。通过使用增强现实技术,可以进行实

时远程协助。智慧城市解决方案还包括导航和城市规划等

AR技术。

移动AR技术

移动设备协同处理能力、硬件摄像头和互联网连接,在

设备显示屏上为用户提供增强现实体验。这种方法可以让公司

接触到大多数用户,因为很多人已经拥有具有增强现实功能的

智能手机。事实上,据AR

Insider称,29%的美国成年人已经体验过移动AR。许多品牌

都利用AR体验来提高客户参与度。2021年,Facebook的AR

功能有2.33亿活跃用户。

开发具有增强现实功能的移动应用程序需要了解适用于

Android和iOS的ARCore和ARKit开发工具。这两个开发平

台支持几乎所有基于移动应用的AR体验。2020年,ARKit拥

有1.47亿用户,而ARCore拥有1.22亿用户;到2021年,这两

个数字分别增至1.92亿和1.82亿用户。

2022年增强现实技术发展重点

克服硬件和软件的限制是增强现实开发的主要挑战之一。

尽管AR技术将在2022年飞速发展,但仍有一些重要的障碍

需要考虑,如移动设备的硬件限制和操作系统版本。其中一个

主要挑战便是Android设备的多样性以及开发者必须面对的独

特规格。理解这些问题是找到解决方案的关键。

writtenby

AndrewMakarov

HeadofMobileDevelopmentatMobiDev

TopMachineLearningBestAgency

maglevDevelopmentCompanyinUkraine

SOFTWAREDEVELOPMENT

FORVISIONARIESWHO

CREATEPRODUCTS

AlANDMACHINEIOT&HARDWARE

LEARNINGINTEGRATION

ForStartupsForEmergingcompaniesForEnterprises

J一

GuaranteeddeliveryYoucanadapttoevolvingTopUS-levelquality

ontimeandonbudgetbusinessneedsandincreaseROIfor1/3thepricetobring

Nosurpriseswithourflexible,provenprocesses3xfeaturestoyourproduct

g2八八4Englishspeaking

450+™100%:Zo;rDUU■professionals

Findmoreat

白info@S/p>

UNITEDSTATESOFFICEUNITEDKINGDOMOFFICEENGINEERINGOFFICESINUKRAINE

Atlanta,GeorgiaSheffieldKharkiv,Chernivtsi,Mykolaiv

TableofContents

AugmentedRealityTechnologiesOverview

MobileAugmentedRealityTechnologies

ARDevelopmentforiOSDevices:ARKil5

LocationAnchors

DepthAPI

RaycastiagAPI

AdvancedFaceTracking

ARDevelopmentforAndroidDevices:ARCore

CloudAnchors

ARFaces

ARImages

RecordingandPlaybackAPIs

ARKi【vsARCorefeaturescomparison

AugmenledRealityDevelopmentForWearables

MicrosoftHoloLens

AugmentedRealityDeveloDmentforSmartGlasses

Web-BasedAugmentedRealityTechnologies

ExampleofWebAR:DellImmersivePortals

LimitationsofWebAR

Where」oStaHDevelopinganARApplication

AugmentedRealityTechnologiesin2022:MainTakeaways

Withtheaugmentedrealitymarketvaluingat$9.5billionUSDandgrowing,this

isanincrediblyimportantsegmenttotakeadvantageoftoremaincompetitive

inARtechnologies-drivenapplicationsforanaudienceof810millionactiveAR

usersonmobile.ThisAugmentedRealityDevelopmentGuidewilltakeyou

throughthemaintechnologies,devicesandplatformsforARappdevelopment

in2022.

1

AugmentedRealityStatisticsin2021

Source:

MOBILEARMARKETSIZE2021

9.5bnUSD

NUMBEROFMOBILEARACTIVEUSERS2021

810m

ARCLASSESUNITSALES2021

410k

mobidev

AugmentedRealityTechnologiesOverview

TheaudienceforARisgrowing.ARtilleryIntelligencereportsthatthemobile

usageofARfeaturesisup29%foradultsintheUnitedStates.Thisismostlydue

todedicatedARappsrunningonthenativeARKitandARCorearchitecturesfor

iPhoneandAndroiddevices.ARtilleryIntelligencealsoreportsthatthereismuch

moreengagementwithARfeaturesthatareincludedwithinappsratherthan

appsbasedentirelyaroundaugmentedreality.

Gaming,social,andvisualsearcharethemostpopularconsumerusecasesfor

AR.It'snosurprisethenthatPokemonGobroughtin$1.92billionUSDin2020

andisexperimentingwithMicrosoftHololenswiththeeventualaimofbringing

wearablegamingexperiencestoalargeraudience.

2

Thetechnologydoesn'tstopwithgeneralconsumers.Manufacturersandsmart

citiesareanotherimportantsegment.ByusingARtechnologies,remote

assistancecanbeperformedinrealtime.Thisallowsforbetterinspectionand

maintenance,aswellastechnicalsupport.SmartcitysolutionsalsoincludeAR

technologieslikenavigationandurbanplanning.

Letstalkmoreaboutthesegroundbreakingandadvancingtechnologiesinour

2022augmentedrealitytechnologyguide.

Augmentedrealityencompassesmanyfacetsofdifferentindustries.Oneofthe

mostusefulwaysofdifferentiatingaugmentedrealitytechnologiesisviathe

hardwarethatisusedastheplatform.Generallyspeaking,thesearemobile

devices,smartglasses,head-mounteddisplays,andwebbasedARfordesktop

andmobiledevices.

AugmentedRealityHardware

MobileSmartImmersiveHeadWeb

DevicesClassesMountedDisplaysBasedAR

SmartphonesGoogleGlassMicrosoftDesktop

TabletsEnterpriseEditionHoloLensMobile

motiidev

Augmentedrealitydevelopmentisveryaccessibleandsimpleapplicationsare

veryeasytogetinto.Togetstarted,abasicunderstandingofgeometryand3D

graphicsisallthat'sneeded.However,morecomplexprojectscanrequiremuch

moreexpertise.MachinelearningandDataSciencecanalsoplayamajorrolein

thedevelopmentofmoreadvancedAR.

3

MobileAugmentedRealityTechnologies

Mobiledevicessynergizetheprocessingpower,hardwarecamera,andInternet

connectiontodeliveraugmentedrealityexperiencesforusersonthedevice's

display.Thismethodallowscompaniestoreachthemostusersbecauseso

manypeoplealreadyownARcapablesmartphones.Infact,accordingtoAR

Insider,29%ofU.S.adultshavealreadytriedmobileAR.Manybrandstake

advantageofARexperiencestodrivecustomerengagement.In2021,Facebook

saw233millionactiveusersofitsARfeatures.

MobileAR2020-2021:ARKit♦ARCore

Developingaugmentedreality-capableappsformobilerequiresan

understandingofARCoreandARKitdevelopmenttoolsforAndroidandiOS.

Thesetwodevelopmentplatformspowernearlyallapp-basedARexperiences

onmobile.In2020,ARKithad147millionuserscomparedtoARCore^122

million,andin2021thesenumberswere192millionusersand182million

users,respectively.

ARCore'slargerdiversityofAndroiddevicesnecessitatesthatitbemoreflexible

fordifferentsmartphones.LastyearwesawGooglebegintocrowdsource

GoogleMapsStreetViewphotossolongastheymetcertainguidelines.ARCore

softwaremadeitpossibleforuserstotakephotoswiththequalityGooglewas

lookingfortoenhancetheirStreetViewexperience.

4

ARKitseemstooutpaceARCorebyasignificantmargin,butbothhavegrownat

asignificantpacesincetheirinitialintroduction.From2017to2018,13million

downloadsontheAppleAppStorewereAR-kitonlyapps.

ArepositorysearchonGithubshownbelowsuggeststhatdeveloperspreferto

buildappswithARKitoverARCore.

DateARKitrepositoryresultsARCorerepositoryresults

May20203,9671r483

May20214,5041,874

January20224,7702,062

ARDevelopmentforiOSDevices:ARKit5

Letstalkaboutafewnewfeaturesthatcanbeinvaluableforthesuccessofthe

developmentofyourARKitapp.

LOCATIONANCHORS

ARKit4introducedlocationanchors,acrucialfeaturethatallowsdevelopersto

affixvirtualobjectsintherealworldbyusinggeographiccoordinates.Thisallows

forfurtherimmersionthroughvisuallocalization.Withlatitude,longitude,and

elevation,virtualobjectscanbeplacedintotheworldwithevenmoreaccuracy

thanbeforewithgeographicinformation.InARKit5locationanchorshaveseen

someimprovements.

Forexample,locationanchorscoulddisplayathreedimensionaliconortextin

spacenexttoaniconicbuilding.Supportforthisfeaturehasbeenexpandedto

LondonandothercitiesintheUnitedStatesinARKit5.

Oneofthemostgroundbreakingelementsoflocationanchorsishowlocationis

approximated.GPSissimplynotpreciseenoughtoprovidelocationanchorson

auser'sscreen.Toassist,developerscanlookaroundwiththeircameratoallow

thedevicetoscanforfeaturesonbuildingsaroundthem.Byusingthese

architecturalfeaturesinconjunctionwithAppleMapsLookArounddata,ausers

locationcanbebetterapproximatedforlocationanchors.

5

SincelocationanchorsaredependentonAppleMapsdata,thismeansthatifthe

cityisnotsupportedbyAppleMaps,functionalityforlocationanchorsmaybe

limited.

DEPTHAPI

DepthAPIisanothervaluablefeatureofARKit4whichcontinuestoplayan

importantroleinARKit5.Itutilizesoneofthemostpowerfulhardwarefeatures

forARonamobiledevice,theLiDARscannerontheiPadProandPhone12Pro,

12ProMax,13Pro,and13ProMaxsmartphones.Thisenablesmuchbetter

analysisofscenesandallowsforrealworldobjectstooccludevirtualobjects

withmuchbetteraccuracy.

RAYCASTINGAPI

Apple'sRaycastingAPIenablesenhancedobjectplacementinconjunctionwith

depthdata.Thisallowsmuchmoreaccurateplacementofvirtualobjectsona

varietyofsurfaceswhiletakingintoaccounttheircurvatureandangle.For

example,it/spossibletousethistoplaceanobjectonthesideofawalloralong

thecurvesofasofaratherthansimplyflatonthefloor.TheLiDARsensorallows

forthescanningofsurfacestotakeplacemuchmorequicklycomparedto

traditionalmethods.

ADVANCEDFACETRACKING

Duetomorepowerfulsoftware,facetrackingtechnologythatwasoncelimited

toTrueDepthcamerascannowbeusedwithiPhoneswithanA12Bionic

processororgreater.Thisallowsfortoolssuchasfaceanchorstobe

incorporatedintoappfeatures.AlsofacetrackingisnowsupportedbytheUltra

WidecamerainthelatestiPadPro(5thgeneration).Thisfeatureallowsfor

trackingofuptothreefacesatonce.

ThevideobelowshowshowiPhoneemploysAR-basedgaze-trackingtechnology

thatcreatesusecasesfordevicecontrolperformedwitheyes,usedforserving

userswithlimitedabilitiestoallowforahands-freeexperienceandmonitoring.

Combinedwithcomputervision,face-basedARopensupfurtheropportunities

forfacialrecognitionapps.

6

ARDevelopmentforAndroidDevices:ARCore

Inanefforttoremaincompetitive,GooglehaspushedARCorefartoremainone

ofthemostversatileARdevelopmentplatformsintheworld.Letsexploresome

ofthefeaturesthatareusedbydevelopers.

CLOUDANCHORS

Thistoolallowsuserstoplacevirtualobjectsinphysicalspacethatcanbe

viewedbyotherusersontheirowndevices.GooglehasmadesurethatCloud

AnchorscanbeseenbyusersoniOSdevicesaswell.

ThefollowingMobiDevdemodemonstrateshowARCoreobjectdetection

featuresforavirtualusermanual.

AugmentedRealityUserManualSfliObidEvo4

WatchlaterShare

VirtualManualviaAugmentedReality

info@

WatchonQYouTube

ARFACES

ARCoreenablesdeveloperstoworkwithhigh-qualityfacialrenderingsby

generatinga468-point3Dmodel.Masksandfilterscanbeappliedafterthe

user'sfaceisidentified.ThisisoneofthemostpopularusecasesforARapp

features.

ARIMAGES

Virtualbusinesscardsandadvertisingpostersarejustafewoftheapplications

thatarepossiblewithaugmentedrealityimages.2Dmarkerscanbeusedto

implementthesefeaturesaswellasmoreadvancedsolutionslikeARindoor

navigation.

LearnhowanARCore-basedindoornavigationapplicationworksbywatching

thisMobiDevdemo.

AugmentedRealityIndoorNavigationDemo-ARCorebased.口£JIjiL®"

Ll一224、xIWal金■旭®Share

AugmentedReality

arindoornavigation

WatchonOYouTubeinfo@

RECORDINGANDPLAYBACKAPIS

Lastyear,GoogleintroducedanewfeatureforARCorecalledrecordingand

playbackAPIs.ThisallowsdeveloperstorecordvideoswithARmetadata.Using

theIMU'sdepthandmotionsensordata,developerscanrecreatethesame

environmentasinthevideoanduseitforfurthertesting.

UserscanalsobenefitfromrecordingandplaybackAPIs.Forexample,usingthis

feature,userscanapplyAReffectsonpreviouslyrecordedvideos,sincethe

videocancontainmetadataabouttheenvironment.

8

ARKitvsARCorefeaturescomparison

AppleandGooglehavebothpositionedtheirrespectiveARplatforms

competitivelyagainsteachother.Thismeansthatbothwilllikelybecomparable

incapabilityfortheforeseeablefuture.ApplehaspositionedARKitwithaslight

advantagegiventhebettercontroloverthesoftwareandhardwareoftheir

devices.TheLiDARsensorisoneofthemostadvanceddepthsensing

technologiesonamobiledevicecurrentlyavailable.However,itwon'tbelong

beforeAndroiddevelopersstarttopickupthepace.

GoogleandApplearebattlingoverplatforms,installedusers,andmoney.

Apple'slifestylebrandimagehasattractedagreatdealofdeveloperattention

sinceitisperceivedasabettersourceofrevenueforstartupsneedingfunding.

AlthoughdevelopersfavorARKit,Google'sARCore'smarketsizeismuchlarger

andgrowing.

ComparisonofARKitandARCorefeaturesin2022

FMtur*ARKHARCor*

WorWTracking••

imageXtacking••

faceTracking••

CsoTracking••

BodyTracking••

PtenceDetection••

Sc«n«Depth••

ObjectDetection••

SharedAR••

MMhing(UOAR).•

■th*IwtureHp,eMnte<lonthaplMlormandK«ff»ctive'th«toMurei*I«Mornot«v«4abletotdcvttofMre

•tb«fMtur*i»notpm«nt«donth*piMform

Sincetheyaimtoprovidecompetitivefunctionality,bothplatformsoffersimilar

featuresandperformancesuchasmotionsensors,understanding

environments,andinspectingchangesinlightingconditions.

Inthefollowingdemovideo,wedemonstratehowARKitandARCoreperformin

recognizingandaugmentingimages.

9

WatchonOYouTube

ByputtingtheMonaLisapaintingintothecameraframe,theappisableto

animatethesubjectbymakingitblinkhereyes.Thevideodemonstratesthe

differencesinperformancebetweenARKitandARCoreinexecutingthistask.

Despitetheirdifferences,thewaythatARscenesarecalculatedinARCoreand

ARKitarenearlyidentical.However,it'smostlikelythatthereasonwhyARKit

outpacesARCoreinperformanceisbecauseApplehasmuchmorecontrolover

thehardwareandsoftwareoftheirdevices.SincetheydevelopbothiPhones,

iPads,aswellasiOS,ApplecanbetteroptimizethemforARexperiences.

It'scrucialtoensurethatadevelopmentteamisusingthelatesttools,technologies

andapproachesontheproject.Usingoldertoolsposesagreatriskasthere'salways

thechancethattheywillbecomeoutdatedandunsupportedinthenot-too-distant

future.There'salsotheriskthatoutdatedsoftwarewillaffecttheimplementationof

newfeatureslaterdowntheroad.Whileitmayworkperfectlynow,youmustthinkof

thefuture.

RomanMarkov

//

Android/iOSExpert

10

AugmentedRealityDevelopmentFor

Wearables

Whenwetalkaboutwearabletechnologyforaugmentedreality,wetypicallyare

referringtodisplaytechnologystrappedtoone'sheadorapairofglasses.

Althoughtheshapeandformfactorofthistechnologycanvary,themost

popularformsaregearlikeMicrosoftHoloLensandmoreportableand

comfortableglasseslikeGoogleGlass.

Thereisabigdifferencebetweenthesetwotypesofdevices,notonlyinpurpose

butinpotential.Largerhead-mounteddisplayslikeHoloLensarecapableof

muchhigherprocessingpower.Thisenablesthemtoprovideexperiences

otherwisecurrentlyimpossibleformorecompactdeviceslikeGoogleGlass.

Becauseofthesmallerformfactorandreducedprocessingpower,ARglasses

aremorefocusedonprovidingtwodimensionalexperiencessimilartothatof

yoursmartphone.Forexample,displayingnotifications,text,directions,photos,

inyourfieldofvisionaresolutionsthatARglassescanreasonablyprovide.

Voice-basedInternetsearchandcontrolarealsofeasible.GoogleGlassandthe

nowdiscontinuedFocalsbyNorthonlyprojectthisinformationintooneeyein

twodimensions.Futureglassesmaybeabletoprojectthisinformationintoboth

eyes.

Hearablesarealsoenteringrelevancy.Technologieslikespatialaudioare

alreadymakingtheirwayontoearbudsliketheAirPodsPro,andmore

office-centrichearableslikeMicrosoft'sSurfaceEarbuds.

Glassesandlargerhead-mounteddisplayshavetwodifferentrolesinthe

marketatthemomentwithspecificusecases.Let'stalkaboutbothofthemin

moredetail.

MICROSOFTHOLOLENS

HoloLenswasfirstannouncedin2015,howeveritsinitialversionwas

discontinued.CurrentlyMicrosoftisofferingHoloLens2tobusinessconsumers

only.Itisbatterypoweredanddoesnotrequireacabledconnectiontoanother

device.AlthoughHoloLens2hasshownenoughpromisetobeacquiredbythe

11

militaryina$22billiondollardeal,thelimitationsandcostoftheproductare

largebarrierspreventingitfrombeingadoptedmorewidely.

Organizationsfacesignificantchallengeswhenadoptingtechnologieslike

HoloLensatscale.Incorporatingnewtechnologiescanbedifficultforbusinesses

becausetheyneedtimeandefforttoadjustandlearntousethem.HoloLens

requiresanentirelynewwayofworkingwithothersandinformation.Thiscalls

intoquestionwhattheimpactwillbenotonlyonthebusinessitselfbutonthe

qualityofitscustomerservice.

MagicLeap,anARheadsetpositionedasapotentialcompetitortoHoloLens,

wasdiscontinuedin2020.

AUGMENTEDREALITYDEVELOPMENTFORSMART

GLASSES

SmartglasseshavegreatpotentialtobecomewhattheiPhonewasfor

consumersintheaugmentedrealityspace.Beingabletohaveacomfortableto

wearandfashionableplatformforaugmentedrealityexperiencesthatcouldbe

massproducedandaffordableforconsumerswouldbegamechangingfor

manyindustries,especiallyretail.

ARexperiencesonsmartphonesareusefulandhelpful.However,viewingvirtual

objectsthroughasmartphoneasaportalcanbeinconvenient.Itsmuchmore

comfortableandrealistictoseevirtualobjectsthroughyournaturalfieldof

visionviasmartglasses.Thiscouldfundamentallychangemanyindustries,

especiallyretail.

However,therearemanychallengeswhenattemptingtomaketechnologythis

sleekandthispowerful.FashionableARglasseswon'tbeabletodonearlythe

samekindsofgraphicallychallengingtasksthatlargerheadsetscan.

FocalsbyNorthwereanotableARGlassesstartuprecentlyacquiredbyGoogle.

Theywereambitiousbutlimited,andhavesincebeendiscontinued.This

suggeststhatGooglemaybeinterestedinbringingbacksmartglassesintothe

mainstream.DreamGlass4Kisanothersmartglassesprojectthatcanbepaired

withasmartphone.

12

Web-BasedAugmentedRealityTechnologies

Althoughthemajorityofusersareexperiencingaugmentedrealitythrough

mobileapps,thisisnottheonlywaytoexperiencethetechnology.Web-based

ARisamoreaccessibleavenueofdevelopmentthatdoesnotrequireusersto

downloadapps.Instead,theARexperiencesareloadedthroughawebbrowser

onadevice.

AR-compatibleDevicesandActiveUsers2020-2021

mobibev

Thisiscrucialduetoappretention.Apptentivereportsthatafterjustonemonth,

anappmayloseonaverageabout35%ofitsusers.Ifusersdon*thaveto

downloadanapptoexperienceARcontent,theywillbemuchmoredriven

towardengagingwithit.

EXAMPLEOFWEBAR:DELLIMMERSIVEPORTALS

DelPsWebARImmersivePortalsareagreatexampleofwebAR.Whenstepping

throughthesevirtual4portals#placedinphysicalspace,userscouldimmerse

themselvesinanewdestinationelsewhereintheworld.AR3Dbusinesscards

areanotherusefulapplicationcreatedbyAircards.Theseexperiencesare

startedbyscanningaQRcodeonthebackofthebusinesscard.Whenviewed

throughadevice,thebusinesscardbecomesfullyanimatedin3Dspace.

ThisMobiDevdemoshowshowAR3Dbusinesscardswork.Youcanalsolearn

moreaboutithere.

13

LIMITATIONSOFWEBAR

SinceWebARapplicationsareextremelylimitedbythewebbrowsersthattheyrunin,WebAR

isnotagreatsolutionforcomplexprojects.WebARmaybesufficientforsimpleprojectssuch

asvirtualbusinesscards,simplefacetrackingandothersolutions.However,formore

complexoperations,mobileARismuchmorecapablesinceitcanunlockthefullpotentialof

themobiledevicethatitsrunningon.Hopefullyinthefuturetechnologywillimproveto

make]AfebARmorecapabletoallowformoreaccessibleARexperiences.

ThekeyforsuccessofWeb-basedARwillbeagreaternumberofdevicestosupportitand

morewebsitestohaveitenabled.Althoughthesestandardshaveyettobeestablished,the

implementationofARinbrowsersisalsoperformedbymeansofeitherportingexisting

libraries(e.g.AR.js)ordevelopingnewones(e.g,A-Frame,React360).

YuriyLuchaninov

JavaScriptGroupLeader

14

WheretoStartDevelopinganARApplication

Onceyou'vedecidedtodevelopanARapp,ther

温馨提示

  • 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
  • 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
  • 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
  • 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
  • 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
  • 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
  • 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

评论

0/150

提交评论