新能源汽车专业英语2版 课件19 - 10.3 环境感知技术

回顾10.1WhatisanIntelligentVehicle?什么是智能汽车？likeahumanthathaveeyes,brainandfeetandcan“see”,"think“and"judge"and"walk"

10.2ConnectedandAutonomousVehicles网联汽车和自动驾驶汽车theabilitytoestablishareliabletwowaycommunicationchannelbetweenthevehicleandvehicleorinfrastructure

本次课学习内容本次课学习目标10.3.1IntelligentVisualPerception智能视觉感知10.3.2Ultrasonicsensor，Millimeter-WaveRadarandLaserRadar超声波传感器、毫米波雷达与激光雷达10.3.3SensorFusionTechnology传感器融合技术1.Intelligentvehiclevisionperceptionsystem：componentsandfunction2.Principleoflaserradar3.FunctionandarchitecturesofSensorFusion10.3EnvironmentPerceptionTechnology环境感知技术讲授新课NewWordsandPhrases10.3EnvironmentPerceptionTechnology环境感知技术perception[pə'sepʃn]n.知觉;觉察pickup['pɪkʌp]n.收集，传感，皮卡recognition[ֽrekəg'nɪʃn]n.认识，识别collision[kə'lɪʒn]n.碰撞，冲突vision['vɪʒn]n.视力，视觉algorithm['ælgərɪðəm]n.运算法则，算法scatter['skætə(r)]vt.（使）散开，（使）分散10.3EnvironmentPerceptionTechnology环境感知技术photoelectric[ֽfəʊtəʊɪ'lektrɪk]adj.光电的peripheral[pə'rɪfərəl]adj.周围的map[mæp]n.地图；vt.绘制地图coordination[kəʊֽɔ:dɪ'neɪʃn]n.协调，和谐all-round[ɔ:l

raʊnd]adj.全面的，综合性的real-time['ri:l'taɪm]adj.（计算机）即时处理的，实时的corresponding[ֽkɒrə'spɒndɪŋ]adj.相当的，对应的gyroscope['dʒaɪrəskəʊp]n.陀螺仪yaw[jɔ:]n.偏航10.3EnvironmentPerceptionTechnology环境感知技术visualperception视觉感知imagesensor图像传感器millimeter-waveradar毫米波雷达laserradar激光雷达blindspotmonitoring盲区监测lanechangeassist变道辅助laneholdassist车道保持辅助10.3EnvironmentPerceptionTechnology环境感知技术lanedeparturewarning车道偏离预警parkassist驻车辅助driverlesscar无人驾驶汽车detectionsignal探测信号reflectedsignal反射信号lasertransmitter激光发射器laserreceiver激光接收器visiblelight可见光infraredlight红外光10.3EnvironmentPerceptionTechnology环境感知技术directdetectionlaserradar直接探测激光雷达laserimagingradar成像激光雷达imagingsystem成像系统connectedandautomatedvehicle(CAV)网联与自动驾驶汽车prioriknowledge先验知识high-definition(HD)map高精地图centralizedfusionarchitecture集中式融合架构distributedfusionarchitecture分布式融合架构hybridfusionarchitecture混合式融合架构10.3EnvironmentPerceptionTechnology环境感知技术10.3.1IntelligentVisualPerception智能视觉感知Visualperceptioncombinestheimageinformationpickupandprocessing,recognitionandunderstandingintoawhole.Oncethecarhasintelligentvisualfunction,itisthesameasthecarhasbotheyesandmind.Suchavehiclecannaturallyreplacethedriveronthevehicletoobserveandcaptureallkindsofinformationaroundit,sothatitcaneffectivelyavoidrear-endcollisions,avoidobstaclesandpreventpedestriansfromaccidentalinjury.Anintelligentvehiclevisualperceptionsystemincludestwoparts:hardwaresystemandsoftwarealgorithm.Amongthem,thehardwaresystemismainlycomposedofimagesensorsandon-boardembeddedsystems(on-boardcomputer)(seeFigure10.6).InFigure10.6,videocamerasasimagesensorsareusedtodetecttrafficlights,pedestrians,cyclists,stationaryormovingobstaclesandthevehiclesthatmaybeencounteredintheprocessofmoving.10.3EnvironmentPerceptionTechnology环境感知技术10.3EnvironmentPerceptionTechnology环境感知技术Figure10.6Basicconfigurationofadriverlessvehicle10.3EnvironmentPerceptionTechnology环境感知技术ThemostrecentversionsoftypicalTeslavehicles(e.g.,Model3)areequippedwitheightsurroundcamerastocovera360°FOVaroundthevehicleasshowninFigure10.7.Amongthem,twoforward-lookingsidecamerasareplacedonthecenterpillars,twobackward-lookingsidecamerasareplacedbetweenthefrontdoorandthefrontwheel,onerear-viewcameraisatthebackofthevehicleclosetothetrunkhandle,andthreeforward(wideangle,main,andnarrowfield)camerasareinsidethevehicleatthetopofthefrontwindshieldclosetotherear-viewmirror.10.3EnvironmentPerceptionTechnology环境感知技术10.3EnvironmentPerceptionTechnology环境感知技术UltrasonicSensorUltrasonicwaveisamechanicalwavewithaveryshortwavelength(generallylessthan2cminair).Thelowerbandofultrasonicwaveisbeyondtheauditoryrangeofthehumanear.Ultrasonicsensorsworkusingthecharacteristicsofultrasonicwaves.Anultrasonicsensorismainlycomposedoftransmitter,receiver,datastorageunitandmicrocontroller.10.3.2UltrasonicSensor，Millimeter-WaveRadarandLaserRadar超声波传感器、毫米波雷达与激光雷达10.3EnvironmentPerceptionTechnology环境感知技术Boththetransmitterandthereceiveraremountedonthesamesideofthesensorcircuitboard.Thetransmitteremitsultrasonicwaves(emittingwaves)ataspecificfrequency.Whenultrasonicwaveencountersthedetectionobject(obstacle),itwillbereflectedbackbythedetectedobject.Whenthereceiverreceivesthereturnedultrasonicwave(reflectedwave),themicrocontrollercalculatesthedistancebetweentheultrasonicsensorandthedetectedobjectbasedontheTOF(timeofflight)oftheultrasonicwave.10.3EnvironmentPerceptionTechnology环境感知技术Theadvantagesofultrasonicsensorsincludesimplestructure,smallsizeandlowcost;strongpenetrationinsevereweatherconditions;andinsensitivitytolightandcolor,thismakingthemsuitableforuseinthedark.Itsmaindisadvantageisshortdetectiondistance,lessfunction(onlyranging),andslowrangingspeed.Ultrasonicsensorsaremainlyusedforparkingassistancesystemandlateralassistsystem.10.3EnvironmentPerceptionTechnology环境感知技术InOctober2016,Teslaannouncedthatitwouldhaveupdatedhardwarekitsonallmodels,with12ultrasonicsensorsimprovingthedetectionrange,forwardradarprovidingmoreinformation,andeightsurroundcamerasprovidinga360-degreeviewwithin250meters（seeFigure10.7）.Millimeter-WaveRadarAmillimeterwaveisanelectromagneticwavewithawavelengthof1-10mmandafrequencyrangeof30-300GHz.Millimeter-waveradarisaradarthatworksinthemillimeterband.10.3EnvironmentPerceptionTechnology环境感知技术Theadvantagesofmillimeter-waveradararelongdetectiondistance,highresolution,fastresponsespeed,goodadaptabilitytoextremeweatherconditions（i.e.rain,snowandfog）andstronganti-interferenceability.Itsdisadvantagesarethatthecoverageareaisscalloped,sothereareblindspots,andtrafficsignalsandtrafficsignscannotbeidentified.Millimeter-waveradarismainlyusedinadaptivecruise,frontcollisionwarning，automaticemergencybraking,lanechangeassistanceandfrontvehicleandpedestriandetection.10.3EnvironmentPerceptionTechnology环境感知技术Thecomponentsofmillimeter-waveradarmainlyincludetransmitter,receiver,signalprocessorandantenna.Thetransmittercontinuouslytransmitsthemillimeterwavepulsesignaltoobject,thereceiverreceivesthemillimeterwave(echo)reflectedfromtheobjectthroughtheantenna,thesignalprocessorprocessesthesignalandcalculatestheTOF(timeofflight)ofthemillimeterwavepulse,soastoobtainthedistancebetweentheradarandtheobject(ranging).Bycalculatingthefrequencychangeofthereturnedmillimeter-wavesignals,themovementspeedoftheobjectrelativetotheradarisobtained(speedmeasurement).10.3EnvironmentPerceptionTechnology环境感知技术Theazimuthangleoftheobjectcanbecalculatedbythephasedifferenceofmillimeter-wavesignalsreceivedbymeansoftheparallelantennaandreflectedbythesameobject.Millimeter-waveradars(usinga"three-in-the-frontandone-in-the-back"configurationmethod，inFigure10.6）areusedtodetectfixedobstaclesinalongdistance,andappliedtoblindspotmonitoring,lanechangeassist,laneholdassist,lanedeparturewarning,andparkassistsystems.10.3EnvironmentPerceptionTechnology环境感知技术LaserradarAlaserradarisaradarsystemthatusesalaserbeamtodetectthelocationandspeedofatarget.Theprincipleoflaserradaristotransmitadetectionsignaltothetarget(laserbeams),thenthetargetreflectedsignal(targetecho)iscomparedwiththetransmittedsignal,andtherelevantinformationofthetarget(forexample,theparameterssuchasthetargetdistance,height,speed,evenshape,etc.)canbeobtainedafterproperprocessing.Thelaserradarismadeupofalasertransmitter,alaserreceiverandaninformationprocessingsystem.10.3EnvironmentPerceptionTechnology环境感知技术Thelasercanbedividedintovisiblelightwave,shortwaveinfraredlight,mediumandlongwaveinfraredlightandlongwaveinfraredlight.Theprincipleoflaserradarisveryclosetothatofthemillimeterwaveradar.However,theformeruseslaserasasignalsourceandlaserpulsesemittedbylaserscausescatteringtoobjects,suchastrees,roads,bridgesandbuildingsontheground.Thisisthebasicprincipleofthedirectdetectionlaserradar.10.3EnvironmentPerceptionTechnology环境感知技术Whenthetargetiscontinuouslyscannedbyapulsedlaser,thedataofallthetargetpointscanalsobeobtained.Afterthat,theaccurate3Dimagecanbeobtainedbyusingthisdata.Thisisthebasicprincipleofthelaserimagingradar.Directdetectionradarandlaserimagingradararealllikelytobeappliedtointelligentcarsordriverlesscars.Theformerisusedtodetectthedistanceandspeedofobstaclesaroundthevehicle,andthelatterisusedformappingobjects.10.3EnvironmentPerceptionTechnology环境感知技术Laserimagingradar(Figure10.7)isacombinationoflaserradarandphotoelectricimagingsystem.Thelaserimagingradarisusedtoaccuratelymapthe3Dimagesintheperipheral200mrange.Figure10.7Laserimagingradar10.3EnvironmentPerceptionTechnology环境感知技术10.3.3SensorFusionTechnology传感器融合技术Toestimatethesurroundingenvironmentoftheconnectedandautomatedvehicle(CAV),somesensorssuchascameras,LiDAR,andmillimeter-wavesensorareutilizedinsomecombinationway.ThesesensorscouldcontributerelevantinformationtoafusionelectroniccontrolunitoftheCAV.Toprovideredundantfunctionality,andincreasetherobustnessofCAVperceptionandlocalization,multipletechniquestoobtainandmergedataareemployed.10.3EnvironmentPerceptionTechnology环境感知技术Inadditiontothesereal-timesensordata,aprioriknowledgeoftheenvironmentcanbeprovidedbyhigh-definition(HD)mapswiththepotentialtoshowinformationabouttheimmediatesurroundingssuchaslanewidth,roadwaycurvature,andtheroadgradient.Byprovidingthesedatainadvance,theprioriinformationfromHDmapsmayreducethereal-timecomputationalloadontheCAVsincetheinformationcanbeprocessedandsynthesizedbeforethevehiclereachesagivenlocation.Itmayalsoobviatetheneedforcertainreal-timesensingcapabilities,potentiallyreducingoverallhardwarecostsand/orprocessingtime.10.3EnvironmentPerceptionTechnology环境感知技术CentralizedFusionArchitectureCentralizedfusionarchitecture(asshowninFigure10.9),alsoknownaslow-levelfusionorsignal-levelfusion,isfundamentallythesimplestofthethreearchitectures.Inthistypeofarchitecture,allsensordataareprocessedinonecentralprocessor.Thus,thedatafusionalgorithmisusedtomanipulatetherawdata,notprocesseddata.Therefore,flaweddatabecomeseasytobedetectedsincetherearefewerprocessorsactingondata,andallrawdataareprocessedtogether.10.3EnvironmentPerceptionTechnology环境感知技术Itisimportanttonotethatthesingle-pointprocessingofcentralizedfusionarchitecturerequiresspatialandtemporalalignmentofsensors.Ifthisalignmentforanysensorisbiasedorskewed,rawdatafromnon-correspondingpointsinspaceortimecouldproduceerroneousstateestimationresults.TheMultipleHypothesisTracking(MHT)algorithmisanexemplarydatafusionalgorithmoftenusedwithacentralizedfusionarchitecture.StateestimationusingMHTisachievedbyeitherrevisingthepreviouslypredictedstateinaprocessknownastrack-orientedMHTorbyevaluatingallpossiblestatestrackingglobalhypothesesbyhypothesis-orientedMHT.10.3EnvironmentPerceptionTechnology环境感知技术Figure10.9Acentralizedfusionarchitecture10.3EnvironmentPerceptionTechnology环境感知技术Thesetechniquesarewellsuitedtothecentralizedarchitecturebecause,sincerawdataareavailablethroughasingleprocessor,thefusionalgorithmhasaccesstoalloftherawdatacollectedbythesystem.Althoughitisusefulforthefusionalgorithmtohaveaccesstoalloftherawdata,thisdoescreatetheneedformorecomplexfusionalgorithmsandcomputationalpowersincenoneofthedataispreprocessedpriortoenteringthecentralizedprocessor.10.3EnvironmentPerceptionTechnology环境感知技术DistributedFusionArchitectureAdistributedfusionarchitectureisalsoknownashigh-levelfusionordecision-levelfusion.Inthisapproach,theinputdatatothecentralprocessorfromeachsensorarepreprocessed.Thepreprocessingactivitycanoccurinthetime,frequency,orpixel-baseddomain.Thedegreeofpreprocessingcanvaryfromsimplenoisefilteringtofullobjectidentificationandclassification.Figure10.10presentsanexampleofthedistributedfusionhighlightingthelocalpreprocessingpriortospatialandtemporalalignmentandfusion.10.3EnvironmentPerceptionTechnology环境感知技术Figure10.10Adistributedfusionarchitecture10.3EnvironmentPerceptionTechnology环境感知技术Thedistributedfusionarchitectureapproachcontrastswiththecentralizedapproach,loweringthecomputationaldemandonthefusioncenterbytakingadvantageofpreprocessingstepsforportionsofthedata.Explicitspatialandtemporalali