汽车英文文献

1Ahighspeedtri-visionsystemforautomotiveapplicationsMarcAnthonyAzzopardi&IvanGrech&JacquesLeconteAbstractPurposeCamerasareexcellentwaysofnon-invasivelymonitoringtheinteriorandexteriorofvehicles.Inparticular,highspeedstereovisionandmultivisionsystemsareimportantfortransportapplicationssuchasdrivereyetrackingorcollisionavoidance.Thispaperaddressesthesynchronisationproblemwhichariseswhenmultivisioncamerasystemsareusedtocapturethehighspeedmotioncommoninsuchapplications.MethodsAnexperimental,high-speedtri-visioncamerasystemintendedforreal-timedrivereye-blinkandsaccademeasurementwasdesigned,developed,implementedandtestedusingprototype,ultra-highdynamicrange,automotive-gradeimagesensorsspecificallydevelopedbyE2V(formerlyAtmel)GrenobleSAaspartoftheEuropeanFP6project–SENSATION(advancedsensordevelopmentforattentionstress,vigilanceandsleep/wakefulnessmonitoring).ResultsThedevelopedsystemcansustainframeratesof59.8Hzatthefullstereovisionresolutionof1280×480butthiscanreach750Hzwhena10kpixelRegionofInterest(ROI)isused,withamaximumglobalshuttespeedof1/48000sandashutterefficiencyof99.7%.ThedatacanbereliablytransmitteduncompressedoverstandardcopperCamera-Link®cablesover5metres.Thesynchronisationerrorbetweentheleftandrightstereoimagesislessthan100psandthishasbeenverifiedbothelectricallyandoptically.Synchronisationisauto-maticallyestablishedatboot-upandmaintainedduringresolutionchanges.Athirdcamerainthesetcanbeconfiguredindependently.Thedynamicrangeofthe10bitsensorsexceeds123dBwithaspectralsensitivityextendingwellintotheinfra-redrange.ConclusionThesystemwassubjectedtoacomprehensivetestingprotocol,whichconfirmsthatthesalientrequire-mentsforthedrivermonitoringapplicationareadequatelymetandinsomerespects,exceeded.Thesynchronizationtechniquepresentedmayalsobenefitseveralotherauto-motivestereovisionapplicationsincludingnearandfar-fieldobstacledetectionandcollisionavoidance,roadconditionmonitoringandothers.KeywordsSynchronisation.High-speedautomotivemultivision.Activesafety.Drivermonitoring.Sensors21IntroductionOverthecomingyears,oneoftheareasofgreatestresearchanddevelopmentpotentialwillbethatofautomotivesensorsystemsandtelematics[1,2].Inparticular,thereisasteeplygrowinginterestintheutilisationofmultiplecameraswithinvehiclestoaugmentvehicleHuman-MachineInterfacing(HMI)forsafety,comfortandsecurity.Forexternalmonitoringapplications,camerasareemergingasviablealternativestosystemssuchRadio,SoundandLight/LaserDetectionandRanging(RADAR,SODAR,LADAR/LIDAR).Thelatteraretypicallyrathercostlyandeitherhavepoorlateralresolutionorrequiremechanicalmovingparts.Forvehiclecabinapplications,camerasoutshineothertechniqueswiththeirabilitytocollectlargeamountsofinformationinahighlyunobtrusiveway.Moreover,camerascanbeusedtosatisfyseveralapplicationsatoncebyre-processingthesamevisiondatainmultipleways,therebyreducingthetotalnumberofsensorsrequiredtoachieveequivalentfunctionality.However,automotivevisionstillfacesseveralopenchallengesintermsofoptoelectronic-performance,size,reliability,powercon-sumption,sensitivity,multi-camerasynchronisation,inter-facingandcost.Inthispaper,severaloftheseproblemsareaddressed.Asanexample,driverheadlocalisation,pointofgazedetectionandeyeblinkratemeasurementisconsideredforwhichthedesignofadash-board-mountableautomotivestereovisioncamerasystemispresented.ThiswasdevelopedaspartofalargeFP6IntegratedProject-SENSATION(AdvancedSensorDevelopmentforAttention,Stress,VigilanceandSleep/WakefulnessMonitoring).Theoverarchinggoalofextendabletomultivisionsystems[5–8].Thecamerasystemisbuiltaroundamatchedsetofprototype,ultra-highdynamicrange,automotive-grade,imagesensorsspecificallydevelopedandfabricatedbyE2VGrenobleSAforthisapplication.Thesensorwhichisanoveltyinitsownright,istheAT76C410ABACMOSmonochromeautomotiveimagesensor.Thissensorimple-mentsaglobalshuttertoallowdistortion-freecaptureoffastmotion.Italsoincorporatesanon-chipMulti-ROIfeaturewithuptoeightRegionsOfInterest(ROI)withpre-programmingfacilityandallowsfastswitchingfromoneimagetoanother.Inthisway,severalreal-timeparallelimagingprocessingtaskscanbecarriedoutwithonesensor.EachROIisindependentlyprogrammableon-the-flywith3respecttointegrationtime,gain,sub-sampling/binning,position,widthandheight.Afairlycomprehensiveseriesof“benchtests”wereconductedinordertotestthevalidityofthenewconceptsandtoinitiallyverifythereliabilityofthesystemacrossvarioustypicalautomotiveoperatingconditions.Additionalrigoroustestingwouldofcoursebeneededtoguaranteeameantimebeforefailure(MTBF)andtodemonstratetheefficacyoftheproposeddesigntechniquesoverstatisticallysignificantproductionquantities.2ApplicationbackgroundThesetofconceivableautomotivecameraapplicationsisanever-growinglistwithsomemarketresearchreportsclaimingover10cameraswillberequiredpervehicle[9].Theincompletelistincludesoccupantdetection,occupantclassification,driverrecognition,drivervigilanceanddrowsinessmonitoring[10],roadsurfaceconditionmoni-toring,intersectionassistance[11],lane-departurewarning[12],blindspotwarning,surroundview,collisionwarning,mit