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WHITEPAPER
AIinvideoanalytics
Considerationsforanalyticsbasedonmachinelearninganddeeplearning
March2021
PAGE
10
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TableofContents
Summary
3
Introduction
4
AI,machinelearning,anddeeplearning
4
Machinelearning
4
Deeplearning
5
Classicalmachinelearningvs.deeplearning
6
Thestagesofmachinelearning
6
Datacollectionanddataannotation
7
Training
7
Testing
8
Deployment
9
Edge-basedanalytics
9
Hardwareacceleration
9
AIisstillinitsearlydevelopment
9
Considerationsforoptimalanalyticsperformance
10
Imageusability
10
Detectiondistance
11
Alarmsandrecordingsetup
11
Maintenance
12
Privacyandpersonalintegrity
13
Appendix
14
Neuralnetworks
14
Convolutionalneuralnetworks(CNN)
15
Summary
AI-basedvideoanalyticsisoneofthemostdiscussedtopicsinthevideosurveillanceindustry.Someoftheapplicationscansubstantiallyspeedupdataanalysisandautomaterepetitivetasks.ButAIsolutionstodaycannotreplacethehumanoperator’sexperienceanddecision-makingskills.Thestrengthliesinsteadinacombination:takingadvantageofAIsolutionstoimproveandincreasehumanefficiency.
TheAIconceptincorporatesmachinelearningalgorithmsanddeeplearningalgorithms.Bothtypesautomaticallybuildamathematicalmodel,usingsubstantialamountsofsampledata(trainingdata),togaintheabilitytocalculateresultswithoutbeingspecificallyprogrammedforit.AnAIalgorithmisdevelopedthroughaniterativeprocess,inwhichacycleofcollectingtrainingdata,labelingtrainingdata,usingthelabeleddatatotrainthealgorithm,andtestingthetrainedalgorithm,isrepeateduntilthedesiredqualitylevelisreached.Afterthis,thealgorithmisreadytouseinananalyticsapplicationwhichcanbepurchasedanddeployedonasurveillancesite.Atthispoint,allthetrainingisdoneandtheapplicationwillnotlearnanythingnew.
AtypicaltaskforAI-basedvideoanalyticsistovisuallydetecthumansandvehiclesinavideostreamanddistinguishwhichiswhich.Amachinelearningalgorithmhaslearnedthecombinationofvisualfeaturesthatdefinestheseobjects.Adeeplearningalgorithmismorerefinedandcan-iftrainedforit-detectmuchmorecomplexobjects.Butitalsorequiressubstantiallylargereffortsfordevelopmentandtrainingandmuchmorecomputationresourceswhenthefinalizedapplicationisused.Forwell-specifiedsurveillanceneeds,itshouldthereforebeconsideredwhetheradedicated,optimizedmachinelearningapplicationcanbesufficient.
AlgorithmdevelopmentandincreasingprocessingpowerofcamerashavemadeitpossibletorunadvancedAI-basedvideoanalyticsdirectlyonthecamera(edgebased)insteadofhavingtoperformthecomputationsonaserver(serverbased).Thisenablesbetterrealtimefunctionalitybecausetheapplicationshaveimmediateaccesstouncompressedvideomaterial.Withdedicatedhardwareaccelerators,suchasMLPU(machinelearningprocessingunit)andDLPU(deeplearningprocessingunit),inthecameras,edge-basedanalyticscanbemorepower-efficientlyimplementedthanwithaCPUorGPU(graphicsprocessingunit).
BeforeanAI-basedvideoanalyticsapplicationisinstalled,themanufacturer’srecommendationsbasedonknownpreconditionsandlimitationsmustbecarefullystudiedandfollowed.Everysurveillanceinstallationisunique,andtheapplication’sperformanceshouldbeevaluatedateachsite.Ifthequalityisfoundto
belowerthanexpected,investigationsshouldbemadeonaholisticlevel,andnotfocusonlyontheanalyticsapplicationitself.Theperformanceofvideoanalyticsisdependentonmanyfactorsrelatedtocamerahardware,cameraconfiguration,videoquality,scenedynamics,andillumination.Inmanycases,knowingtheimpactofthesefactorsandoptimizingthemaccordinglymakesitpossibletoincreasevideoanalyticsperformanceintheinstallation.
AsAIisincreasinglyappliedinsurveillance,theadvantagesofoperationalefficiencyandnewusecasesmustbebalancedwithamindfuldiscussionaboutwhenandwheretoapplythetechnology.
Introduction
AI,artificialintelligence,hasbeendevelopedanddebatedeversincethefirstcomputerswereinvented.Whilethemostrevolutionaryincarnationsarenotyethere,AI-basedtechnologiesarewidelyusedtodayforcarryingoutclearlydefinedtasksinapplicationssuchasvoicerecognition,searchengines,andvirtualassistants.AIisalsoincreasinglyemployedinhealthcarewhereitprovidesvaluableresourcesin,forexample,x-raydiagnosticsandretinascananalysis.
AI-basedvideoanalyticsisoneofthemostdiscussedtopicsinthevideosurveillanceindustryandexpectationsarehigh.ThereareapplicationsonthemarketthatuseAIalgorithmstosuccessfullyspeedupdataanalysisandautomaterepetitivetasks.Butinawidersurveillancecontext,AItodayandinthenearfutureshouldbeviewedasjustoneelement,amongseveralothers,intheprocessofbuildingaccuratesolutions.
Thiswhitepaperprovidesatechnologicalbackgroundonmachinelearninganddeeplearningalgorithmsandhowtheycanbedevelopedandappliedforvideoanalytics.ThisincludesabriefaccountofAIaccelerationhardwareandtheprosandconsofrunningAI-basedanalyticsontheedgecomparedtoonaserver.ThepaperalsotakesalookathowthepreconditionsforAI-basedvideoanalyticsperformancecanbeoptimized,takingawidescopeoffactorsintoaccount.
AI,machinelearning,anddeeplearning
Artificialintelligence(AI)isawideconceptassociatedwithmachinesthatcansolvecomplextaskswhiledemonstratingseeminglyintelligenttraits.DeeplearningandmachinelearningaresubsetsofAI.
Artificialintelligence
Machinelearning
Deeplearning
Machinelearning
MachinelearningisasubsetwithinAIthatusesstatisticallearningalgorithmstobuildsystemsthathavetheabilitytoautomaticallylearnandimproveduringtrainingwithoutbeingexplicitlyprogrammed.
Inthissection,wedistinguishbetweentraditionalprogrammingandmachinelearninginthecontextofcomputervision—thedisciplineofmakingcomputersunderstandwhatishappeninginascenebyanalyzingimagesorvideos.
Traditionallyprogrammedcomputervisionisbasedonmethodsthatcalculateanimage’sfeatures,forexample,computerprogramslookingforpronouncededgesandcornerpoints.Thesefeaturesneedtobemanuallydefinedbyanalgorithmdeveloperwhoknowswhatisimportantintheimagedata.Thedeveloperthencombinesthesefeaturesforthealgorithmtoconcludewhatisfoundinthescene.
Machinelearningalgorithmsautomaticallybuildamathematicalmodelusingsubstantialamountsofsampledata–trainingdata–togaintheabilitytomakedecisionsbycalculatingresultswithout
specificallybeingprogrammedtodoso.Thefeaturesarestillhand-craftedbuthowtocombinethesefeaturesislearnedbythealgorithmitselfthroughexposuretolargeamountsoflabeled,orannotated,trainingdata.Inthispaper,werefertothistechniqueofusinghand-craftedfeaturesinlearnedcombinations,asclassicalmachinelearning.
Inotherwords,foramachinelearningapplicationweneedtotrainthecomputertogettheprogramwewant.Dataiscollectedandthenannotatedbyhumans,sometimesassistedwithpre-annotationbyservercomputers.Theresultisfedintothesystemandthisprocessgoesonuntiltheapplicationhaslearnedenoughtodetectwhatwewanted,forexample,aspecifictypeofvehicle.Thetrainedmodelbecomestheprogram.Notethatwhentheprogramisfinishedthesystemdoesnotlearnanythingnew.
Traditionalprogramming:
Dataiscollected.Programcriteriaaredefined.Theprogramiscoded(byahuman).Done.
Machinelearning:
Dataiscollected.Dataislabeled.Themodelundergoesaniterativetrainingprocess.Thefinalizedtrainedmodelbecomestheprogram.Done.
TheadvantageofAIovertraditionalprogramming,whenbuildingacomputervisionprogram,istheabilitytoprocessextensivedata.Acomputercangothroughthousandsofimageswithoutlosingfocus,whereasahumanprogrammerwillgettiredandunfocusedafterawhile.Thatway,theAIcanmaketheapplicationsubstantiallymoreaccurate.However,themorecomplicatedtheapplication,theharderitisforthemachinetoproducethewantedresult.
Deeplearning
Deeplearningisarefinedversionofmachinelearninginwhichboththefeatureextractionandhowtocombinethesefeatures,indeepstructuresofrulestoproduceanoutput,arelearnedinadata-drivenmanner.Thealgorithmcanautomaticallydefinewhatfeaturestolookforinthetrainingdata.Itcanalsolearnverydeepstructuresofchainedcombinationsoffeatures.
Thecoreofthealgorithmsusedindeeplearningisinspiredbyhowneuronsworkandhowthebrainusesthesetoformhigher-levelknowledgebycombiningtheneuronoutputsinadeephierarchy,oranetwork,
ofchainedrules.Thebrainisasysteminwhichthecombinationsthemselvesarealsoformedbyneurons,erasingthedistinctionbetweenfeatureextractionandthecombinationoffeatures,makingthemthesameinsomesense.Thesestructuresweresimulatedbyresearchersintosomethingcalledartificialneuralnetworks,whichisthemostwidelyusedtypeofalgorithmindeeplearning.Seetheappendixofthisdocumentforabriefoverviewofneuralnetworks.
Usingdeeplearningalgorithms,itispossibletobuildintricatevisualdetectorsandautomaticallytrainthemtodetectverycomplexobjects,resilienttoscale,rotation,andothervariations.
Thereasonbehindthisflexibilityisthatdeeplearningsystemscanlearnfromamuchlargeramountofdata,andmuchmorevarieddata,thanclassicalmachinelearningsystems.Inmostcases,theywillsignificantlyoutperformhand-craftedcomputervisionalgorithms.Thismakesdeeplearningespecially
suitedforcomplexproblemswherethecombinationoffeaturescannoteasilybeformedbyhumanexperts,suchasimageclassification,languageprocessing,andobjectdetection.
Objectdetectionbasedondeeplearningcanclassifycomplexobjects.Inthisexample,theanalyticsapplicationcannotonlydetectvehicles,butalsoclassifythetypeofvehicle.
Classicalmachinelearningvs.deeplearning
Whiletheyaresimilartypesofalgorithms,adeeplearningalgorithmtypicallyusesamuchlargersetoflearnedfeaturecombinationsthanaclassicalmachinelearningalgorithmdoes.Thismeansthatdeeplearning-basedanalyticscanbemoreflexibleandcan-iftrainedto-learntoperformmuchmorecomplextasks.
Forspecificsurveillanceanalytics,however,adedicated,optimizedclassicalmachinelearningalgorithmcanbesufficient.Inawellspecifiedscope,itcanprovidesimilarresultsasadeeplearningalgorithmwhilerequiringlessmathematicaloperationsandcanthereforebemorecost-efficientandlesspowerconsumingtouse.Itfurthermorerequiresmuchlesstrainingdataandthisgreatlyreducesthedevelopmenteffort.
Thestagesofmachinelearning
Thedevelopmentofamachinelearningalgorithmfollowsaseriesofstepsanditerations,roughlyvisualizedbelow,beforeafinalizedanalyticsapplicationcanbedeployed.Attheheartofananalyticsapplicationis
oneormorealgorithms,forexampleanobjectdetector.Inthecaseofdeeplearningbasedapplicationsthecoreofthealgorithmisthedeeplearningmodel.
Preparation:Definingthepurposeoftheapplication.
Training:Collectingtrainingdata.Annotatingthedata.Trainingthemodel.Testingthemodel.Ifqualityisnotasexpected,thepreviousstepsaredoneagaininaniterativeimprovementcycle.
Deployment:Installingandusingthefinishedapplication.
Datacollectionanddataannotation
TodevelopanAI-basedanalyticsapplicationyouneedtocollectlargeamountsofdata.Invideosurveillance,thistypicallyconsistsofimagesandvideoclipsofhumansandvehiclesorotherobjectsofinterest.Inordertomakethedatarecognizableforamachineorcomputeradataannotationprocessisnecessary,wheretherelevantobjectsarecategorizedandlabeled.Dataannotationismainlyamanualandlabor-intensetask.Theprepareddataneedstocoveralarge-enoughvarietyofsamplesthatarerelevantforthecontextwheretheanalyticsapplicationwillbeused.
Training
Training,orlearning,iswhenthemodelisfedannotateddataandatrainingframeworkisusedtoiterativelymodifyandimprovethemodeluntilthedesiredqualityisreached.Inotherwords,themodelisoptimizedtosolvethedefinedtask.Trainingcanbedoneaccordingtooneofthreemainmethods.
Supervisedlearning:themodellearnstomakeaccuratepredictions
Unsupervisedlearning:Themodellearnstoidentifyclusters
Reinforcementlearning:Themodellearnsfrommistakes
Supervisedlearning
Supervisedlearningisthemostusedmethodinmachinelearningtoday.Itcanbedescribedaslearningbyexamples.Thetrainingdataisclearlyannotated,meaningthattheinputdataisalreadypairedwiththedesiredoutputresult.
Supervisedlearninggenerallyrequiresaverylargeamountofannotateddataandtheperformanceofthetrainedalgorithmisdirectlydependentonthequalityofthetrainingdata.Themostimportantqualityaspectistouseadatasetthatrepresentsallpotentialinputdatafromarealdeploymentsituation.Forobjectdetectors,thedevelopermustmakesuretotrainthealgorithmwithawidevarietyofimages,withdifferentobjectsinstances,orientations,scales,lightsituations,backgrounds,anddistractions.Onlyifthetrainingdataisrepresentativefortheplannedusecase,thefinalanalyticsapplicationwillbeabletomakeaccuratepredictionsalsowhenprocessingnewdata,unseenduringthetrainingphase.
Unsupervisedlearning
Unsupervisedlearningusesalgorithmstoanalyzeandgroupunlabeleddatasets.Thisisnotacommontrainingmethodinthesurveillanceindustry,becausethemodelrequiresalotofcalibrationandtestingwhilethequalitycanstillbeunpredictable.
Thedatasetsmustberelevantfortheanalyticsapplicationbutdonothavetobeclearlylabeledormarked.Themanualannotationworkiseliminated,butthenumberofimagesorvideosneededforthetrainingmustbegreatlyincreased,byseveralordersofmagnitude.Duringthetrainingphase,theto-be-trainedmodelisidentifying,supportedbythetrainingframework,commonfeaturesinthedatasets.Thisenablesitto,duringthedeploymentphase,groupdataaccordingtopatternswhilealsoallowingittodetectanomalieswhichdonotfitintoanyofthelearnedgroups.
Reinforcementlearning
Reinforcementlearningisusedin,forexample,robotics,industrialautomation,andbusinessstrategyplanning,butduetotheneedforlargeamountsoffeedback,themethodhaslimiteduseinsurveillancetoday.Reinforcementlearningisabouttakingsuitableactiontomaximizethepotentialrewardinaspecificsituation,arewardthatgetslargerwhenthemodelmakestherightchoices.Thealgorithmdoesnotusedata/labelpairsfortraining,butisinsteadoptimizedbytestingitsdecisionsthroughinteractionwiththeenvironmentwhilemeasuringthereward.Thegoalofthealgorithmistolearnapolicyforactionsthatwillhelpmaximizethereward.
Testing
Oncethemodelistrained,itneedstobethoroughlytested.Thissteptypicallycontainsanautomatedpartcomplementedwithextensivetestinginreal-lifedeploymentsituations.
Intheautomatedpart,theapplicationisbenchmarkedwithnewdatasets,unseenbythemodelduringitstraining.Ifthesebenchmarksarenotwheretheyareexpectedtobe,theprocessstartsoveragain:newtrainingdataiscollected,annotationsaremadeorrefinedandthemodelisretrained.
Afterreachingthewantedqualitylevel,afieldteststarts.Inthistest,theapplicationisexposedtorealworldscenarios.Theamountandvariationdependonthescopeoftheapplication.Thenarrowerthescope,thelessvariationsneedtobetested.Thebroaderthescope,themoretestsareneeded.
Resultsareagaincomparedandevaluated.Thisstepcanthenagaincausetheprocesstostartover.Anotherpotentialoutcomecouldbetodefinepreconditions,explainingaknownscenarioinwhichtheapplicationisnotoronlypartlyrecommendedtobeused.
Deployment
Thedeploymentphaseisalsocalledinferenceorpredictionphase.Inferenceorpredictionistheprocessofexecutingatrainedmachinelearningmodel.Thealgorithmuseswhatitlearnedduringthetrainingphasetoproduceitsdesiredoutput.Inthesurveillanceanalyticscontext,theinferencephaseistheapplicationrunningonasurveillancesystemmonitoringreallifescenes.
Toachievereal-timeperformancewhenexecutingamachinelearningbasedalgorithmonaudioorvideoinputdata,specifichardwareaccelerationisgenerallyrequired.
Edge-basedanalytics
High-performancevideoanalyticsusedtobeserverbasedbecausetheyrequiredmorepower,andcooling,thanacameracouldoffer.ButalgorithmdevelopmentandincreasingprocessingpowerofedgedevicesinrecentyearshavemadeitpossibletorunadvancedAI-basedvideoanalyticsontheedge.
Thereareobviousadvantagesofedgebasedanalyticsapplications:theyhaveaccesstouncompressedvideomaterialwithverylowlatency,enablingrealtimeapplicationswhileavoidingtheadditionalcostandcomplexityofmovingdataintothecloudforcomputations.Edgebasedanalyticsalsocomewithlowerhardwareanddeploymentcostssincelessserverresourcesareneededinthesurveillancesystem.
Someapplicationsmaybenefitfromusingacombinationofedgebasedandserverbasedprocessing,withpreprocessingonthecameraandfurtherprocessingontheserver.Suchahybridsystemcanfacilitatecost-efficientscalingofanalyticsapplicationsbyworkingonseveralcamerastreams.
Hardwareacceleration
Whileyoucanoftenrunaspecificanalyticsapplicationonseveraltypesofplatforms,usingdedicatedhardwareaccelerationachievesamuchhigherperformancewhenpowerislimited.Hardwareacceleratorsenablepower-efficientimplementationofanalyticsapplications.Theycanbecomplementedbyserverandcloudcomputeresourceswhensuitable.
GPU(graphicsprocessingunit).GPUsweremainlydevelopedforgraphicsprocessingapplicationsbutarealsousedforacceleratingAIonserverandcloudplatforms.Whilesometimesalsousedinembeddedsystems(edge),GPUsarenotoptimal,fromapowerefficiencystandpoint,formachinelearninginferencetasks.
MLPU(machinelearningprocessingunit).AnMLPUcanaccelerateinferenceofspecificclassicalmachinelearningalgorithmsforsolvingcomputervisiontaskswithveryhighpowerefficiency.Itisdesignedforreal-timeobjectdetectionofalimitednumberofsimultaneousobjecttypes,forexample,humansandvehicles.
DLPU(deeplearningprocessingunit).Cameraswithabuilt-inDLPUcanaccelerategeneraldeeplearningalgorithminferencewithhighpowerefficiency,allowingforamoregranularobjectclassification.
AIisstillinitsearlydevelopment
ItistemptingtomakeacomparisonbetweenthepotentialofanAIsolutionandwhatahumancanachieve.Whilehumanvideosurveillanceoperatorscanonlybefullyalertforashortperiodoftime,acomputercankeepprocessinglargeamountsofdataextremelyquicklywithoutevergettingtired.
ButitwouldbeafundamentalmisunderstandingtoassumethatAIsolutionswouldreplacethehuman
operator.Therealstrengthliesinarealisticcombination:takingadvantageofAIsolutionstoimproveandincreasetheefficiencyofahumanoperator.
Machinelearningordeeplearningsolutionsareoftendescribedashavingthecapabilitytoautomaticallylearnorimprovethroughexperience.ButAIsystemsavailabletodaydonotautomaticallylearnnewskillsafterdeploymentandwillnotrememberspecificeventsthathaveoccurred.Toimprovethesystem’sperformance,itneedstoberetrainedwithbetterandmoreaccuratedataduringsupervisedlearningsessions.Unsupervisedlearningtypicallyrequiresalotofdatatogenerateclustersandisthereforenotusedinvideosurveillanceapplications.Itisinsteadusedtodaymainlyforanalyzinglargedatasetstofindanomalies,forexampleinfinancialtransactions.Mostapproachesthatarepromotedas“self-learning”withinvideosurveillancearebasedonastatisticaldataanalysisandnotonactuallyretrainingthedeeplearningmodels.
HumanexperiencestillbeatsmanyAI-basedanalyticsapplicationsforsurveillancepurposes.Especiallythosewhicharesupposedtoperformverygeneraltasksandwherecontextualunderstandingiscritical.Amachinelearningbasedapplicationmightsuccessfullydetecta“runningperson”ifspecificallytrainedforitbutunlikeahumanwhocanputthedataintocontext,theapplicationhasnounderstandingofwhythepersonisrunning–tocatchthebusorfleefromthenearbyrunningpoliceofficer?DespitepromisesfromcompaniesapplyingAIintheiranalyticsapplicationsforsurveillance,theapplicationcannotyetunderstandwhatitseesonvideowithremotelythesameinsightasahumancan.
Forthesamereason,AI-basedanalyticsapplicationscanalsotriggerfalsealarmsormissalarms.Thiscouldtypicallyhappeninacomplexenvironmentwithalotofmovement.Butitcouldalsobeabout,forexample,apersoncarryingalargeobject—effectivelyobstructingthehumancharacteristicstotheapplication,makingacorrectclassificationlesslikely.
AI-basedanalyticstodayshouldbeusedinanassistingway,forexample,toroughlydeterminehowrelevantanincidentisbeforealertingahumanoperatortodecideabouttheresponse.Thisway,AIisusedtoreachscalabilityandthehumanoperatoristheretoassesspotentialincidents.
Considerationsforoptimalanalyticsperformance
TonavigatethequalityexpectationsofanAI-basedanalyticsapplication,itisrecommendedtocarefullystudyandunderstandtheknownpreconditionsandlimitations,typicallylistedintheapplication’sdocumentation.
Everysurveillanceinstallationisuniqueandtheapplication’sperformanceshouldbeevaluatedateachsite.Ifthequalityisnotattheexpectedoranticipatedlevel,itisstronglyrecommendedtonotonlyfocustheinvestigationontheapplicationitself.Allinvestigationsshouldbemadeonaholisticlevelbecausetheperformanceofananalyticsapplicationdependsonsomanyfactors,mostofwhichcanbeoptimizedifweareawareoftheirimpact.Thesefactorsinclude,forexample,camerahardware,videoquality,scenedynamics,illuminationlevel,aswellascameraconfiguration,position,anddirection.
Imageusability
Imagequalityisoftensaidtodependonhighresolutionandhighlightsensitivityofthecamera.Whiletheimportanceofthesefactorscannotbequestioned,therearecertainlyothersthatarejustasinfluentialfortheactualusabilityofanimageoravideo.Forexample,thebestqualityvideostreamfromthemostexpensivesurveillancecameracanbeuselessifthesceneisnotsufficientlylitatnight,ifthecamerahasbeenredirected,orifthesystemconnectionisbroken.
Theplacementofthecamerashouldbecarefullyconsideredbeforedeployment.Forvideoanalyticstoperformasexpected,thecameraneedstobepositionedtoenableaclearview,withoutobstacles,oftheintendedscene.
Imageusabilitymayalsodependontheusecase.Videothatlooksgoodtoahumaneyemaynothavetheoptimalqualityfortheperformanceofavideoanalyticsapplication.Infact,manyimageprocessingmethodsthatarecommonlyusedtoenhancevideoappearanceforhumanviewingarenotrecommendedwhenusingvideoanalytics.Thismayinclude,forexample,appliednoisereductionmethods,widedynamicrangemethods,orautoexposurealgorithms.
VideocamerastodayoftencomewithintegratedIRilluminationwhichenablesthemtoworkincompletedarkness.Thisispositiveasitmayenablecamerastobeplacedondifficult-lightsitesandreducetheneedforinstallingadditionalillumination.However,ifheavyrainorsnowfallareexpectedonasite,itishighlyrecommendednottorelyonlightcomingfromthecameraorfromalocationveryclosetothecamera.
Toomuchlightmaybedirectlyreflectedbacktothecamera,againstraindropsandsnowflakes,makingtheanalyticsunabletoperform.Withambientlight,ontheotherhand,thereisabetterchancethattheanalyticswilldeliversomeresultsevenindifficultweather.
Detectiondistance
ItisdifficulttodetermineamaximumdetectiondistanceofanAI-basedanalyticsapplication—anexactdatasheetvalueinmetersorfeetcanneverbethewholetruth.Imagequality,scenecharacteristics,weatherconditions,andobjectpropertiessuchascolorandbrightnesshaveasignificantimpactonthedetectiondistance.Itisevident,forexample,thatabrightobjectagainstadarkbackgroundduringasunnydaycanbevisuallydetectedatmuchlongerdistancesthanadarkobjectonarainyday.
Thedetectiondistancealsodependsonthespeedoftheobjectstobedetected.Toachieveaccurateresults,avideoanalyticsapplicationneedsto“see”theobjectduringasufficientlylongperiodoftime.Howlongthatperiodneedstobedependsontheprocessingperformance(framerate)oftheplatform:thelowertheprocessingperformance,thelongertheobjectneedstobevisibleinordertobedetected.Ifthecamera’sshuttertimeisnotwellmatchedwiththeobjectspeed,motionblurappearingintheimagemayalsolowerthedetectionaccuracy.
Fastobjectsmaybemoreeasilymissediftheyarepassingbyclosertothecamera.Arunningpersonlocatedfarfromthecamera,forexample,mightbewelldetected,whileapersonrunningveryclosetothecameraatthesamespeedmaybeinandoutofthefieldofviewsoquicklythatnoalarmistriggered.
Inanalyticsbasedonmovementdetection,objectsmovingdirectlytowardsthecamera,orawayfromit,presentanotherchallenge.Detectionwillbeespeciallydifficultforslow-movingobjects,whichwillonlycauseverysmallchangesintheimagecomparedtomovementacrossthescene.
Ahigherresolutioncameratypicallydoesnotprovidealongerdetectiondistance.Theprocessingcapabilitiesneededforexecutingamachinelearningalgorithmareproportionaltothesizeoftheinputdata.Thismeansthatth
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