Download - Face Recognition Vendor Test FRVT 2018 Performance of ... · PDF fileFace Recognition Vendor Test FRVT 2018 Performance of Automated Face Identification Algorithms Concept, Evaluation

FaceRecognitionVendorTestFRVT2018

PerformanceofAutomatedFaceIdentificationAlgorithmsConcept,EvaluationPlanandAPI

VERSION0.5

THISDOCUMENTISOPENFORCOMMENTS:[email protected]

PatrickGrotherMeiNgan

KayeeHanaokaInformationAccessDivision

InformationTechnologyLaboratory

October26,2017

FaceRecognitionVendorTest1:N

NIST Concept,EvaluationPlanandAPI Page2of18

TableofContents11. FRVT2018.........................................................................................................................................................................32

1.1. Scope......................................................................................................................................................................331.2. Audience.................................................................................................................................................................341.3. Schedule.................................................................................................................................................................351.4. Reporting................................................................................................................................................................361.5. VersionControl.......................................................................................................................................................371.6. Background.............................................................................................................................................................481.7. FRVT2018:Changesfrompriorevaluations...........................................................................................................491.8. Relationtothe1:1FRVTevaluation.......................................................................................................................4101.9. Coreaccuracymetrics.............................................................................................................................................4111.10. Applicationrelevance.............................................................................................................................................512

2. Rulesforparticipation......................................................................................................................................................5132.1. Participationagreement.........................................................................................................................................5142.2. Validation................................................................................................................................................................5152.3. Hardwarespecification...........................................................................................................................................5162.4. Operatingsystem,compilation,andlinkingenvironment......................................................................................6172.5. Softwareanddocumentation.................................................................................................................................6182.6. Runtimebehavior...................................................................................................................................................7192.7. Timelimits..............................................................................................................................................................8202.8. Templatesizelimits................................................................................................................................................821

3. DatastructuressupportingtheAPI..................................................................................................................................9223.1. Requirement...........................................................................................................................................................9233.2. Fileformatsanddatastructures.............................................................................................................................924

4. APIspecification.............................................................................................................................................................13254.1. Namespace...........................................................................................................................................................13264.2. Overview...............................................................................................................................................................13274.3. API.........................................................................................................................................................................1528

29ListofTables30

Table1–Scheduleandallowednumberofsubmissions.........................................................................................................331Table3–Processingtimelimitsinseconds,per640x480colorimage,onasingleCPU.......................................................832Table4–Structureforasingleimage......................................................................................................................................933Table5–LabelsdescribingcategoriesofImages.....................................................................................................................934Table6–Structureforasetofimagesfromasingleperson...................................................................................................935Table7–Structureforapairofeyecoordinates...................................................................................................................1036Table8–Labelsdescribingtemplaterole..............................................................................................................................1037Table9–Enrollmentdatasettemplatemanifest...................................................................................................................1138Table10–Labelsdescribinggallerycomposition..................................................................................................................1239Table11–Structureforacandidate......................................................................................................................................1240Table12–Enumerationofreturncodes................................................................................................................................1241Table13–ReturnStatusstructure.........................................................................................................................................1342Table16–Proceduraloverviewofthe1:Ntest.....................................................................................................................1343Table17–Templatecreationinitialization............................................................................................................................1544Table19–Enrollmentfinalization..........................................................................................................................................1645Table21–Identificationsearch.............................................................................................................................................1746Table23–Insertionoftemplateintoagallery......................................................................................................................1847Table24–Removaloftemplatefromagallery.....................................................................................................................184849

50



1. FRVT201851

1.1. Scope52Thisdocumentestablishesaconceptofoperationsandanapplicationprogramminginterface(API)forevaluationofone-53to-manyfacerecognitionalgorithmsappliedtofacesappearingin2Dstillphotographs.Theprimaryfocusofthetestis54cooperativeportraitimages,e.g.mugshots1.Thetestwillincludealsosearchofnon-cooperativeimages.TheAPI55communicatesthetypeofimagetothealgorithm.56

1.2. Audience57

Participationisopentoanyorganizationworldwide,primarilyresearchersanddevelopersofFRalgorithms.WhileNIST58intendstoevaluatestabletechnologiesthatcouldbereadilymadeoperational,thetestisalsoopentoexperimental,59prototypeandothertechnologies.AllalgorithmsmustbesubmittedasimplementationsoftheAPIdefinedinthis60document.Thereisnochargeforparticipation.61

1.3. Schedule62InconsultationwithUSGovernmentcollaborators,NISTwillexecutetheFRVT2018ontheschedulegiveninTable1.Note63thatNISTwillreportresultspubliclyattheendofPhases2and3.TheendofPhase2correspondscloselytotheendof64thefinancialyearandresultsfromtheFRVTarerequiredbythatdate.65

Developersmaysubmitthenumberofalgorithmsidentifiedintherightmostcolumn.66

Table1–Scheduleandallowednumberofsubmissions67Phase Date Milestone Maximumnumberof

implementationsAPIDevelopment

2017-10-26 Draftevaluationplanavailableforpubliccomments 2017-11-16 Finalevaluationplanpublished

Phase1

2018-01-22 Participationstarts:AlgorithmsmaybesenttoNIST 2018-02-16 LastdayforsubmissionofalgorithmstoPhase1 32018-05-23 Interimresultsreleased

Phase2

2018-06-21 LastdayforsubmissionofalgorithmstoPhase2 22018-09-20 Resultsreleased

Phase3

2018-10-19 LastdayforsubmissionofalgorithmstoPhase3 22018-12-19 Releaseoffinalpublicreport

1.4. Reporting68AttheconclusionofPhase1,NISTwillprovideresultsforallalgorithmstoalldevelopers,andtoUSGovernmentpartners.69

AttheconclusionofPhase2,NISTwillpublishresultsforallalgorithmsonitswebsite.70

AttheconclusionofPhase3,NISTwillpublishanInteragencyReportsummarizingtheentireFRVT1:N.71

Important:ThisisanopentestinwhichNISTwillidentifythealgorithmandthedevelopingorganization.Algorithm72resultswillbeattributedtothedeveloper.Resultswillbemachinegenerated(i.e.scripted)andwillincludetiming,73accuracyandotherperformanceresults.Thesewillbepostedalongsideresultsfromotherimplementations.74

NISTmayadditionallyreportresultsinworkshops,conferences,conferencepapersandpresentations,journalarticlesand75technicalreports.76

1.5. VersionControl77Developersmustsubmitaversion.txtfileinthedoc/folderthataccompaniestheiralgorithm–seeSection2.5.3.The78stringinthisfileshouldallowthedevelopertoassociateresultsthatappearinNISTreportswiththesubmittedalgorithm.791TheMEDSdatabaseincludessamplemugshots.



Thisisintendedtoallowend-userstoobtainproductizedversionsoftheprototypessubmittedtoNIST.NISTwillpublish80thecontentsofversion.txt.NISThaspreviouslypublishedMD5hashesofthecorelibrariesforthispurpose.81

1.6. Background82NISThasconductedevaluationsoffacerecognitionprototypessincethefirstFRVTin2000.Until2006,thosetrials83simulatedone-to-manysearchaccuracyusingsetsofone-to-onecomparisons.In2010,insupportoftheFBI’s84procurementofafacesearchcapability,NISTreported[NISTIR7709]accuracyandspeedofend-to-endone-to-many85searchimplementationswithenrolledpopulationsupto1.8million.Usingupdatedalgorithms,thattestwasrepeated86andextendedin2013[NIST8009].Thosetestsfocusedoncooperativeportraitimages.Inlate2017,NISTwillpublishthe87resultsfromtheFaceRecognitionPrizeChallengewhichassessedcapabilityofcontemporarysearchalgorithmsonless88constrainedimages[FRPC2017].89

1.7. FRVT2018:Changesfrompriorevaluations90Givenmassivechangesinfacerecognitionsincethelastone-to-manyevaluationin2013,NISTseekstoassessbenefits91thathaveaccruedtotheuseofthosetechnologieswithcooperativeimages.92

Thefollowingarenewaspects:93

― Effectofincreasedpopulationsize:Nisexpectedtoexceed107representinganorderofmagnitudeincreasinginthe94numberofuniquefaces.95

― Accuracywithencounter-basedgalleries:PriorNISTevaluationsconstructedgalleriesinwhichallknownimagesof96anenrolleewereprovidedtothealgorithmtogether,underasingleidentity.Thissupportedalgorithmswhichmight97fuseimagesortemplates.However,thissubject-basedenrollmentdiffersfromthat(minorityof)operational98deployments–encounter-basedapplications-inwhichmultipleimagesofapersonarepresentinadatabase99withoutanyspecifiedidentityorlink.Thistestwillcompareaccuracyforbothsubject-basedandencounter-based100galleries.Section3.2.6containsnarrativeandAPIsupporttoinformthealgorithmofthegallerytype.101

― Expenseofdeletionandinsertionfunctions:PriorNISTevaluationsconstructedagallerywhichwassearched102withoutanymodification.Thisfacilitatedmeasurementofaccuracyandspeedbutdidnotallowformeasurementof103computationalexpenseofaddingordeletingelementsfromthegallery.Thesefunctionsmaynotbetrivial,for104example,iftheunderlyingimplementationusesfast-searchdatastructures.105

1.8. Relationtothe1:1FRVTevaluation106SinceFebruary2017,NISThasbeenrunninganongoingevaluationofone-to-onefaceverificationalgorithms,FRVT1:1.107Thisallowsanydevelopertosubmitalgorithmsatanytime,onceeverythreecalendarmonths,therebybetteraligning108developmentandevaluationschedules.TheFRVT1:1includessixdifferentdatasets,oneofwhichismugshots,similarto109theprimarysetproposedforinclusionontheFRVT1:Ndefinedherein.Itmaybenefitdeveloperstosubmittheircore1:1110recognitionalgorithmstotheFRVT1:1processbytheFRVT1:Ndeadline.Ifsuchcpu-basedalgorithmsaresubmittedby111January22,wewillpublishresultsbeforethe1:Ndeadline.112

ParticipationintheFRVT1:1isnotrequiredforparticipationinFRVT1:N.113

1.9. Coreaccuracymetrics114Thistestwillexecuteopen-universesearches.Thatis,someproportionofsearcheswillnothaveanenrolledmate.From115thecandidatelistsreturnedbyalgorithms,NISTwillcomputeandreportaccuracymetrics,primarily:116

― Falsenegativeidentificationrate(FNIR)–theproportionofmatedsearcheswhichdonotyieldamatewithinthetop117Rranksandatorabovethreshold,T.118

― Falsepositiveidentificationrate(FPIR)–theproportionofnon-matedsearchesreturningany(1ormore)candidates119atoraboveathreshold,T.120

― Selectivity–thenumberofnon-matedcandidatesreturnedatoraboveathreshold,T.Thisquantityhasavalue121runningfrom0toL,thenumberofcandidatesrequested.Itmaybefractional,asitisestimatedasacountdividedby122thenumberofnon-matesearches.123



ThesequantitiesareestimatedfromcandidatelistsproducedbyrequestingthetopLmostsimilarcandidatestothe124search.Wedonotintendtoexecutesearchesrequestingonlythosecandidatesaboveaspecifiedinputthreshold.125

WewillreportFNIRandFPIRbysweepingthethresholdovertheinterval[0,infinity).Errortradeoffplots(FNIRvs.FPIR,126parametriconthreshold)willbetheprimaryreportingmechanism.127

WewillreportalsoFNIRbysweepingarankRovertheinterval[1,L]toproduce(thecomplementof)thecumulative128matchcharacteristic(CMC).129

1.10. Applicationrelevance130NISTanticipatesreportingFNIRintwoFPIRregimes:131

― Investigationmode:Givencandidatelistsandathresholdofzero,theCMCmetricisrelevanttoinvestigational132applicationswherehumanexaminerswilladjudicatecandidatesindecreasingorderofsimilarity.Thisiscommonin133lawenforcement“leadgeneration”.134

― Identificationmode:Wewillapply(high)thresholdstocandidatelistsandreportFNIRvaluesrelevantto135identificationapplicationswherehumanlaborismatchedtothetolerablenumberoffalsepositivesperunittime.136Thisisusedinduplicatedetectionsearchesforcredentialissuanceand,moreso,insurveillanceapplications.137

Giventhatmultiplealgorithmsmaybesubmitted,developersareencouragedtosubmitvariantstailoredtominimizeFNIR138inthetwoFPIRregimes,andtoexplorethespeed-accuracytradespace.139

2. Rulesforparticipation140

2.1. Participationagreement141Aparticipantmustproperlyfollow,complete,andsubmittheFRVTParticipationAgreement.Thismustbedoneonce,142eitherpriororinconjunctionwiththeveryfirstalgorithmsubmission.Itisnotnecessarytodothisforeachsubmitted143implementationthereafter.144

NOTE OrganizationsthathavealreadysubmittedaparticipationagreementforongoingFRVT1:1donotneedtosend145inanewparticipationagreement,astheirsubmissionofa1:Nalgorithmindicatestheyagreetothesametermsand146conditionsarticulatedinthatagreement.147

NOTE Ifanorganizationupdatestheircryptographicsigningkey,theymustsendanewcompletedparticipation148agreementsubmissionforthisevaluation,withthefingerprintoftheirpublickey.149

150

2.2. Validation151AllparticipantsmustruntheirsoftwarethroughtheprovidedFRVT1:Nvalidationpackagepriortosubmission.The152validationpackagewillbemadeavailableathttps://github.com/usnistgov/frvt.Thepurposeofvalidationistoensure153consistentalgorithmoutputbetweentheparticipant’sexecutionandNIST’sexecution.154

2.3. Hardwarespecification155NISTintendstosupporthighperformancebyspecifyingtheruntimehardwarebeforehand.Thereareseveraltypesof156computerbladesthatmaybeusedinthetesting.Eachmachinehasatleast192GBofmemory.Weanticipatethat16157processescanberunwithouttimeslicing,thoughNISTwillhandleallmultiprocessingworkviafork()2.Participant-158initiatedmultiprocessingisnotpermitted.159

Allimplementationsshalluse64bitaddressing.160

NISTintendstosupporthighlyoptimizedalgorithmsbyspecifyingtheruntimehardware.Thereareseveraltypesof161computersthatmaybeusedinthetesting.Thefollowinglistgivessomedetailsaboutpossiblecomputearchitectures:162

2http://man7.org/linux/man-pages/man2/fork.2.html



― DualIntel®Xeon®X56903.47GHzCPUs(6coreseach)3163

― DualIntel®Xeon®[email protected](10coreseach)4164

― DualIntel®Xeon®[email protected](14coreseach)4165

ThistestwillnotsupporttheuseofGraphicsProcessingUnits(GPUs).TheFRVT1:1activity,whichremainsopen,166documentsrelativeGPUvsCPUspeed.167

2.4. Operatingsystem,compilation,andlinkingenvironment168

Theoperatingsystemthatthesubmittedimplementationsshallrunonwillbereleasedasadownloadablefileaccessible169fromhttp://nigos.nist.gov:8080/evaluations/CentOS-7-x86_64-Everything-1511.iso,whichisthe64-bitversionofCentOS1707.2runningLinuxkernel3.10.0.171

Forthistest,MacOSandWindows-compiledlibrariesarenotpermitted.AllsoftwaremustrununderCentOS7.2.172

NISTwilllinktheprovidedlibraryfile(s)toourC++languagetestdrivers.Participantsarerequiredtoprovidetheirlibrary173inaformatthatisdynamically-linkableusingtheC++11compiler,g++version4.8.5.174

Atypicallinklinemightbe175g++ -std=c++11 -I. -Wall -m64 -o frvt1N frvt1N.cpp -L. –lfrvt1N_acme_0 176

TheStandardC++libraryshouldbeusedfordevelopment.Theprototypesfromthisdocumentwillbewrittentoafile177"frvt1N.h"whichwillbeincludedvia#include.178

Theheaderfileswillbemadeavailabletoimplementersathttps://github.com/usnistgov/frvt.Allalgorithmsubmissions179willbebuiltagainsttheofficiallypublishedheaderfiles–developersshouldnotaltertheheaderfileswhencompilingand180buildingtheirlibraries.181

Allcompilationandtestingwillbeperformedonx86_64platforms.Thus,participantsarestronglyadvisedtoverify182library-levelcompatibilitywithg++(onanequivalentplatform)priortosubmittingtheirsoftwaretoNISTtoavoidlinkage183problemslateron(e.g.symbolnameandcallingconventionmismatches,incorrectbinaryfileformats,etc.).184

2.5. Softwareanddocumentation185

2.5.1. Libraryandplatformrequirements186ParticipantsshallprovideNISTwithbinarycodeonly(i.e.nosourcecode).Theimplementationshouldbesubmittedin187theformofadynamically-linkedlibraryfile.188

ThecorelibraryshallbenamedaccordingtoTable2.Additionalsupplementallibrariesmaybesubmittedthatsupport189this“core”libraryfile(i.e.the“core”libraryfilemayhavedependenciesimplementedintheseotherlibraries).190Supplementallibrariesmayhaveanyname,butthe“core”librarymustbedependentonsupplementallibrariesinorder191tobelinkedcorrectly.TheonlylibrarythatwillbeexplicitlylinkedtotheFRVTtestdriveristhe“core”library.192

IntelIntegratedPerformancePrimitives(IPP)®librariesarepermittediftheyaredeliveredasapartofthedeveloper-193suppliedlibrarypackage.Itistheprovider’sresponsibilitytoestablishproperlicensingofalllibraries.TheuseofIPP194librariesshallnotpreventrunningonCPUsthatdonotsupportIPP.PleasetakenotethatsomeIPPfunctionsare195multithreadedandthreadedimplementationsareprohibited.196

NISTwillreportthesizeofthesuppliedlibraries.1973cat/proc/cpuinforeturnsfpuvmedepsetscmsrpaemcecx8apicsepmtrrpgemcacmovpatpse36clflushdtsacpimmxfxsrssesse2sshttmpbesyscallnxpdpe1gbrdtscplmconstant_tscarch_perfmonpebsbtsrep_goodnoplxtopologynonstop_tscaperfmperfpnipclmulqdqdtes64monitords_cplvmxsmxesttm2ssse3cx16xtprpdcmpciddcasse4_1sse4_2popcntaeslahf_lmidaaratdthermtpr_shadowvnmiflexpriorityeptvpid4cat/proc/cpuinforeturnsfpuvmedepsetscmsrpaemcecx8apicsepmtrrpgemcacmovpatpse36clflushdtsacpimmxfxsrssesse2sshttmpbesyscallnxpdpe1gbrdtscplmconstant_tscarch_perfmonpebsbtsrep_goodnoplxtopologynonstop_tscaperfmperfeagerfpupnipclmulqdqdtes64monitords_cplvmxsmxesttm2ssse3fmacx16xtprpdcmpciddcasse4_1sse4_2x2apicmovbepopcnttsc_deadline_timeraesxsaveavxf16crdrandlahf_lmabm3dnowprefetchidaaratepbplnptsdthermtpr_shadowvnmiflexpriorityeptvpidfsgsbasetsc_adjustbmi1hleavx2smepbmi2ermsinvpcidrtmcqmrdseedadxsmapxsaveoptcqm_llccqm_occup_llc



Table2–Implementationlibraryfilenameconvention198Form libfrvt1N_provider_sequence.endingUnderscoredelimitedpartsofthefilename

libfrvt1N provider sequence ending

Description Firstpartofthename,requiredtobethis.

Singleword,non-infringingnameofthemainproviderEXAMPLE:Acme

Aonedigitdecimalidentifiertostartat0andincrementedby1foreachdistinctalgorithmsenttoNIST.Donotincrementthisnumberwhensubmittingbug-fixedupdates.

.so

Example libfrvt1N_acme_0.so

2.5.2. Configurationanddeveloper-defineddata199Theimplementationundertestmaybesuppliedwithconfigurationfilesandsupportingdatafiles.Thesemightinclude,200forexample,model,calibrationorbackgroundfeaturedata.NISTwillreportthesizeofthesuppliedconfigurationfiles.201

2.5.3. Submissionfolderhierarchy202Participantsubmissionsshallcontainthefollowingfoldersatthetoplevel203

― lib/-containsallparticipant-suppliedsoftwarelibraries204

― config/-containsallconfigurationanddeveloper-defineddata205

― doc/-containsversion.txt,whichdocumentsversioninginformationforthesubmittedsoftwareandanyother206participant-provideddocumentationregardingthesubmission207

― validation/-containsvalidationoutput208

2.5.4. Installationandusage209Theimplementationshallbeinstallableusingsimplefilecopymethods.Itshallnotrequiretheuseofaseparate210installationprogramandshallbeexecutableonanynumberofmachineswithoutrequiringadditionalmachine-specific211licensecontrolproceduresoractivation.Theimplementationshallnotusenorenforceanyusagecontrolsorlimitsbased212onlicenses,numberofexecutions,presenceoftemporaryfiles,etc.Theimplementationshallremainoperableforat213leasttwelvemonthsfromthesubmissiondate.214

2.6. Runtimebehavior215

2.6.1. Modesofoperation216ImplementationsshallnotrequireNISTtoswitch“modes”ofoperationoralgorithmparameters.Forexample,theuseof217twodifferentfeatureextractorsmusteitheroperateautomaticallyorbesplitacrosstwoseparatelibrarysubmissions.218

2.6.2. Interactivebehavior,stdout,logging219Theimplementationwillbetestedinnon-interactive“batch”mode(i.e.withoutterminalsupport).Thus,thesubmitted220libraryshall:221

― Notuseanyinteractivefunctionssuchasgraphicaluserinterface(GUI)calls,oranyothercallswhichrequireterminal222interactione.g.readsfrom“standardinput”.223

― Runquietly,i.e.itshouldnotwritemessagesto"standarderror"andshallnotwriteto“standardoutput”.224

― OnlyifrequestedbyNISTfordebugging,includealoggingfacilityinwhichdebuggingmessagesarewrittentoalog225filewhosenameincludestheproviderandlibraryidentifiersandtheprocessPID.226



2.6.3. Exceptionhandling227Theapplicationshouldincludeerror/exceptionhandlingsothatinthecaseofafatalerror,thereturncodeisstill228providedtothecallingapplication.229

2.6.4. Externalcommunication230ProcessesrunningonNISThostsshallnotside-effecttheruntimeenvironmentinanymanner,exceptformemory231allocationandrelease.Implementationsshallnotwriteanydatatoexternalresource(e.g.server,file,connection,or232otherprocess),norreadfromsuch,norotherwisemanipulateit.Ifdetected,NISTwilltakeappropriatesteps,including233butnotlimitedto,cessationofevaluationofallimplementationsfromthesupplier,notificationtotheprovider,and234documentationoftheactivityinpublishedreports.235

2.6.5. Statelessbehavior236Allcomponentsinthistestshallbestateless,exceptasnoted.Thisappliestofacedetection,featureextractionand237matching.Thus,allfunctionsshouldgiveidenticaloutput,foragiveninput,independentoftheruntimehistory.NIST238willinstituteappropriateteststodetectstatefulbehavior.Ifdetected,NISTwilltakeappropriatesteps,includingbutnot239limitedto,cessationofevaluationofallimplementationsfromthesupplier,notificationtotheprovider,and240documentationoftheactivityinpublishedreports.241

2.6.6. Single-threadrequirementandparallelization242Implementationsmustruninsingle-threadedmode,becauseNISTwillparallelizethetestbydividingtheworkloadacross243manycoresandmanymachines.Implementationsmustensurethattherearenoissueswiththeirsoftwarebeing244parallelizedviathefork()function.245

2.7. Timelimits246TheelementalfunctionsoftheimplementationsshallexecuteunderthetimeconstraintsofTable3.Thesetimelimits247applytothefunctioncallinvocationsdefinedinsection4.Assumingthetimesarerandomvariables,NISTcannotregulate248themaximumvalue,sothetimelimitsare90-thpercentiles.Thismeansthat90%ofalloperationsshouldtakelessthan249theidentifiedduration.Timingwillbeestimatedfromatleast1000separateinvocationsofeachelementalfunction.250

Thetimelimitsapplyperimage.251

Table3–Processingtimelimitsinseconds,per640x480colorimage,onasingleCPU252

Function 1:NTemplateGeneration 11:Nfinalization(ongalleryof1millionenrolledtemplates) 400001:Nsearchfor:

- N=1millionenrolledtemplates- L=100returnedcandidates

25

2.8. Templatesizelimits253NISTanticipatesevaluatingperformancewithNwellinexcessof107.Forimplementationsthatrepresentagalleryin254memorywithalineardatastructure,thememoryofourmachinesimpliesalimitontemplatesizes.Thus,foratemplate255sizeB,thetotalmemoryrequirementwouldbeaboutNB.NISTanticipatesrunningthelargestNvaluesonmachines256equippedwith768GBormemory.WithN=25million,templatesshouldnotexceed32KB.257

TheAPI,however,supportsmulti-stagesearchesandreadaccessofthediskduringthe1:Nsearch.Diskaccesswould258likelybeveryslow.Inallcases,algorithmsshallconformtothesearchdurationlimitsgiveninTable3,withlinearscaling.259



3. DatastructuressupportingtheAPI260

3.1. Requirement261FRVT1:NparticipantsshallimplementtherelevantC++prototypedinterfacesofsection4.C++waschoseninorderto262makeuseofsomeobject-orientedfeatures.263

3.2. Fileformatsanddatastructures264

3.2.1. Overview265

Inthisfacerecognitiontest,anindividualisrepresentedbyK³1two-dimensionalfacialimages.Mostimageswillcontain266exactlyoneface.Inasmallfractionoftheimages,other,smaller,faceswillappearinthebackground.Algorithmsshould267detectoneforegroundface(thebiggestone)ineachimageandproduceonetemplate.268

Table4–Structureforasingleimage269C++codefragment Remarkstypedef struct Image { uint16_t width; Numberofpixelshorizontally uint16_t height; Numberofpixelsvertically uint16_t depth; Numberofbitsperpixel.Legalvaluesare8and24. std::shared_ptr<uint8_t> data; Managedpointertorasterscanneddata.EitherRGBcoloror

intensity.Ifimage_depth==24thispointsto3WHbytesRGBRGBRGB...Ifimage_depth==8thispointstoWHbytesIIIIIII

Label description; Singledescriptionoftheimage.TheallowedvaluesforthisfieldarespecifiedintheenumerationinTable5.

} Image;

AnImagewillbeaccompaniedbyoneofthelabelsgivenbelow.Facerecognitionimplementationsshouldtolerate270Imagesofanycategory.271

Table5–LabelsdescribingcategoriesofImages272LabelasC++enumeration Meaningenum class Label { UNKNOWN=0, Eitherthelabelisunknownorunassigned. ISO, Frontal,intendedtobeinconformitytoISO/IEC19794-5:2005. MUGSHOT, Fromlawenforcementbookingprocesses.Nominallyfrontal. PHOTOJOURNALISM, Theimagemightappearinanewssourceormagazine.Theimagesare

typicallytakenbyprofessionalphotographerandarewellexposedandfocusedbutexhibitposeandilluminationvariations.

EXPLOITATION, Theimageistakenfromachildexploitationdatabase.Thisimageryhashighlyunconstrainedposeandillumination,expressionandresolution.

WILD Unconstrainedimage,takenbyanamateurphotographer,exhibitingwidevariationsinpose,illumination,andresolution.

};

Table6–Structureforasetofimagesfromasingleperson273C++codefragment Remarksusing Multiface = std::vector<Image>; VectorofImageobjects



3.2.2. Datastructureforeyecoordinates274Implementationsshallreturneyecoordinatesofeachfacialimage.Thisfunction,whilenotnecessaryforarecognition275test,willassistNISTinassuringthecorrectnessofthetestdatabase.TheprimarymodeofusewillbeforNISTtoinspect276imagesforwhicheyecoordinatesarenotreturned,ordifferbetweenimplementations.277

TheeyecoordinatesshallfollowtheplacementsemanticsoftheISO/IEC19794-5:2005standard-thegeometric278midpointsoftheendocanthionandexocanthion(seeclause5.6.4oftheISOstandard).279

Sense:Thelabel"left"referstosubject'slefteye(andsimilarlyfortherighteye),suchthatxright<xleft.280

Table7–Structureforapairofeyecoordinates281C++codefragment Remarkstypedef struct EyePair { bool isLeftAssigned; Ifthesubject’slefteyecoordinateshavebeencomputedandassigned

successfully,thisvalueshouldbesettotrue,otherwisefalse. bool isRightAssigned; Ifthesubject’srighteyecoordinateshavebeencomputedandassigned

successfully,thisvalueshouldbesettotrue,otherwisefalse. uint16_t xleft; XandYcoordinateofthecenterofthesubject'slefteye.Iftheeye

coordinateisoutofrange(e.g.x<0orx>=width),isLeftAssignedshouldbesettofalse.

uint16_t yleft;

uint16_t xright; XandYcoordinateofthecenterofthesubject'srighteye.Iftheeyecoordinateisoutofrange(e.g.x<0orx>=width),isRightAssignedshouldbesettofalse.

uint16_t yright;

} EyePair;

3.2.3. Templaterole282Labelsdescribingthetype/roleofthetemplatetobegeneratedwillbeprovidedasinputtotemplategeneration.This283supportsasymmetricalgorithmswheretheenrollmentandrecognitiontemplatesmaydifferincontentandsize.284

Table8–Labelsdescribingtemplaterole285LabelasC++enumeration Meaningenum class TemplateRole { Enrollment_1N, Enrollmenttemplatefor1:Nidentification Search_1N Searchtemplatefor1:Nidentification};

3.2.4. Datatypeforsimilarityscores286Identificationandverificationfunctionsshallreturnameasureofthesimilaritybetweenthefacedatacontainedinthe287twotemplates.Thedatatypeshallbeaneight-bytedoubleprecisionreal.Thelegalrangeis[0,DBL_MAX],wherethe288DBL_MAXconstantislargerthanpracticallyneededanddefinedinthe<climits>includefile.Largervaluesindicatemore289likelihoodthatthetwosamplesarefromthesameperson.290

Providersarecautionedthatalgorithmsthatnativelyproducefewuniquevalues(e.g.integerson[0,127])willbe291disadvantagedbytheinabilitytosetathresholdprecisely,asmightberequiredtoattainafalsepositiveidentification292rateofexactly0.0001,forexample.293

3.2.5. Filestructureforenrolledtemplatecollection294Tosupportthis1:Ntest,NISTwillconcatenateenrollmenttemplatesintoasinglelargefile,theEDB(forenrollment295database).TheEDBisasimplebinaryconcatenationofproprietarytemplates.Thereisnoheader.Thereareno296delimiters.TheEDBmaybemanygigabytesinlength.297



Thisfilewillbeaccompaniedbyamanifest;thisisanASCIItextfiledocumentingthecontentsoftheEDB.Themanifest298hastheformatshownasanexampleinTable9.IftheEDBcontainsNtemplates,themanifestwillcontainNlines.The299fieldsarespace(ASCIIdecimal32)delimited.Therearethreefields.Strictlyspeaking,thethirdcolumnisredundant.300

Important:Ifacalltothetemplategenerationfunctionfails,ordoesnotreturnatemplate,NISTwillincludetheTemplate301IDinthemanifestwithsize0.Implementationsmusthandlethisappropriately.302

Table9–Enrollmentdatasettemplatemanifest303Fieldname TemplateID TemplateLength PositionoffirstbyteinEDBDatatyperequired std::string uint64_t uint64_tExamplelinesofamanifestfileappeartotheright.Lines1,2,3andNappear.

90201744 1024 0person01 1536 10247456433 512 2560... subject12 1024 307200000

304TheEDBschemeavoidsthefilesystemoverheadassociatedwithstoringmillionsofsmallindividualfiles.305

3.2.6. GalleryType306

307Figure1–Illustrationofconsolidatedversusunconsolidatedenrollmentdatabase5308

Figure1illustratestwotypesofgalleries:309

― Consolidated:Thedatabaseisformedbyenrollingallimagesofasubjectunderacommonidentitylabel.Theresult310isagallerywithNidentitiesandNtemplates.Thistypeofgallerypresentsuswiththecleanestexperimentaldesign,311“oneneedleinahaystack”scenario.Itallowsalgorithmstoperformimageandfeaturelevelfusion.Operationallyit312requireshighintegritybiographicalinformationtomaintain.313

― Unconsolidated:Thedatabaseisformedbyenrollingphotographswithoutregardtowhetherthesubjectalreadyhas314alreadybeenenrolledornot.Underthisscheme,differentimagesofthesamepersoncanexistinthegalleryunder315differentsubjectidentifiers,thatis,thereareNidentities,andM>Ndatabaseentries.316

Duringgalleryfinalization,algorithmswillbeprovidedwithanenumeratedlabelfromTable10whichspecifiesthetypeof317gallerybeingprocessed.318

5ThefaceimagescontainedinthisfigurearefromthepubliclyavailableSpecialDatabase32-MultipleEncounterDataset(MEDS).https://www.nist.gov/itl/iad/image-group/special-database-32-multiple-encounter-dataset-meds



Table10–Labelsdescribinggallerycomposition319LabelasC++enumeration Meaningenum class GalleryType { Consolidated, Consolidated,subject-basedenrollment Unconsolidated Unconsolidated,event-basedorphoto-basedenrollment};

3.2.7. Datastructureforresultofanidentificationsearch320AllidentificationsearchesshallreturnacandidatelistofaNIST-specifiedlength.Thelistshallbesortedwiththemost321similarmatchingentrieslistfirstwithlowestrank.ThedatastructureshallbethatofTable11.322

Table11–Structureforacandidate323 C++codefragment Remarks1. typedef struct Candidate 2. { 3. bool isAssigned; Ifthecandidatecomputationsucceeded,thisvalueissettotrue.Falseotherwise.

Ifvalueissettofalse,similarityScoreandtemplateIdwillbeignoredentirely.4. std::string templateId; TheTemplateIDfromtheenrollmentdatabasemanifestdefinedinclause3.2.5.5. double similarityScore; Measureofsimilaritybetweentheidentificationtemplateandtheenrolledcandidate.

Higherscoresmeanmorelikelihoodthatthesamplesareofthesameperson.

Analgorithmisfreetoassignanyvalue[0,DBL_MAX]toacandidate.Thedistributionofvalueswillhaveanimpactonthefalse-negativeandfalse-positiveidentificationrates.

6. } Candidate;

3.2.8. DatastructureforreturnvalueofAPIfunctioncalls324

Table12–Enumerationofreturncodes325ReturncodeasC++enumeration Meaningenum class ReturnCode { Success=0, Success ConfigError, Errorreadingconfigurationfiles RefuseInput, Electiverefusaltoprocesstheinput,e.g.becausecannothandlegreyscale ExtractError, Involuntaryfailuretoprocesstheimage,e.g.aftercatchingexception ParseError, Cannotparsetheinputdata TemplateCreationError, Electiverefusaltoproducea“non-blank”template(e.g.insufficientpixels

betweentheeyes) VerifTemplateError, Formatching,eitherorbothoftheinputtemplateswereresultoffailed

featureextraction FaceDetectionError, Unabletodetectafaceintheimage NumDataError, Theimplementationcannotsupportthenumberofimages TemplateFormatError, Templatefileisinanincorrectformatordefective EnrollDirError, Anoperationontheenrollmentdirectoryfailed(e.g.permission,space) InputLocationError, Cannotlocatetheinputdata–theinputfilesornamesseemincorrect MemoryError, Memoryallocationfailed(e.g.outofmemory) NotImplemented, Functionisnotimplemented VendorError, Vendor-definedfailure.Vendorerrorsshallreturnthiserrorcodeand

documentthespecificfailureintheReturnStatus.infostringfromTable13.};

326327328



Table13–ReturnStatusstructure329C++codefragment Meaningstruct ReturnStatus { ReturnCode code; ReturnCode std::string info; Optionalinformationstring // constructors };

330

4. APIspecification331

PleasenotethatincludedwiththeFRVT1:Nvalidationpackage(availableathttps://github.com/usnistgov/frvt)isa“null”332implementationofthisAPI.Thenullimplementationhasnorealfunctionalitybutdemonstratesmechanicallyhowone333couldgoaboutimplementingthisAPI.334

4.1. Namespace335AlldatastructuresandAPIinterfaces/functioncallswillbedeclaredintheFRVTnamespace.336

4.2. Overview337The1:Nidentificationapplicationproceedsinthreephases:enrollment,finalizationandidentification.Theidentification338phaseincludesseparateprobefeatureextractionandsearchstages.339

Thedesignreflectsthefollowingtestingobjectivesfor1:Nimplementations.340

- supportdistributedenrollmentonmultiplemachines,withmultipleprocessesrunninginparallel- allowrecoveryafterafatalexception,andmeasurethenumberofoccurrences- allowNISTtocopyenrollmentdataontomanymachinestosupportparalleltesting- respecttheblack-boxnatureofbiometrictemplates- extendcompletefreedomtotheprovidertousearbitraryalgorithms- supportmeasurementofdurationofcorefunctioncalls- supportmeasurementoftemplatesize- supportmeasurementoftemplateinsertionandremovaltimesintoanenrollmentdatabase

Table14–Proceduraloverviewofthe1:Ntest341

Phase # Name Description PerformanceMetricstobe

reportedbyNIST

Enrollm

ent

E1 Initialization initializeTemplateCreation(TemplateRole=Enrollment_1N)

Givetheimplementationthenameofadirectorywhereanyprovider-suppliedconfigurationdatawillhavebeenplacedbyNIST.Thislocationwillotherwisebeempty.

Theimplementationispermittedread-onlyaccesstotheconfigurationdirectory.

E2 ParallelEnrollment createTemplate(TemplateRole=Enrollment_1N)

ForeachofNindividuals,passK=1imageoftheindividualtotheimplementationforconversiontoatemplate.Theimplementationwillreturnatemplatetothecallingapplication.

NIST'scallingapplicationwillberesponsibleforstoringalltemplatesasbinaryfiles.Thesewillnotbeavailabletotheimplementationduringthisenrollmentphase.

Multipleinstancesofthecallingapplicationmayrunsimultaneouslyorsequentially.Thesemaybeexecutingondifferentcomputers.

Statisticsofthetimesneededtoenrollanindividual.

Statisticsofthesizesofcreatedtemplates.

Theincidenceoffailedtemplatecreations.

E3 Finalization finalizeEnrollment()

Permanentlyfinalizetheenrollmentdirectory.Thissupports,forexample,adaptation

Sizeoftheenrollmentdatabaseasafunctionof



oftheimage-processingfunctions,adaptationoftherepresentation,writingofamanifest,indexing,andcomputationofstatisticalinformationovertheenrollmentdataset.

Theimplementationispermittedread-write-deleteaccesstotheenrollmentdirectoryduringthisphase.

populationsizeN.

Durationofthisoperation.Thetimeneededtoexecutethisfunctionshallbereportedwiththeprecedingenrollmenttimes.

Prob

eTemplateCreatio

n

S1 Initialization initializeTemplateCreation(TemplateRole=Search_1N)

Givetheimplementationthenameofadirectorywhereanyprovider-suppliedconfigurationdatawillhavebeenplacedbyNIST.Thislocationwillotherwisebeempty.

Theimplementationispermittedread-onlyaccesstotheconfigurationdirectory.

Statisticsofthetimeneededforthisoperation.

S2 Templatepreparation

createTemplate(TemplateRole=Search_1N)

Foreachprobe,createatemplatefromK>=1image.

Theresultofthisstepisasearchtemplate.Multipleinstancesofthecallingapplicationmayrunsimultaneouslyorsequentially.Thesemaybeexecutingondifferentcomputers.


Statisticsofthesizeofthesearchtemplate.

Search

S3 Initialization initializeIdentification()

Telltheimplementationthelocationofanenrollmentdirectory.Theimplementationshouldreadallorsomeoftheenrolleddataintomainmemory,sothatsearchescancommence.

Theimplementationispermittedread-onlyaccesstotheenrollmentdirectoryduringthisphase.


S4 Search identifyTemplate()

Atemplateissearchedagainsttheenrollmentdatabase.

DevelopersshallnotattempttoimprovethedurationoftheidentifyTemplate()functionbyoffloadinganyofitsprocessingintothecreateTemplate()function.


Accuracymetrics-TypeI+IIerrorrates.

Failurerates.

GalleryIn

sertand

Rem

ove

G1 Initialization initializeIdentification()

Telltheimplementationthelocationofanenrollmentdirectory.Theimplementationshouldreadallorsomeoftheenrolleddataintomainmemory,sothatsearchescancommence.

Theimplementationispermittedread-onlyaccesstotheenrollmentdirectoryduringthisphase.

Statisticsofthedurationoftheoperation.

G2 Templateinsertion/removalinto/fromgallery

galleryInsertID()/galleryDeleteID()

galleryInsertID()isexecutedoneormoretimestoinsertatemplatecreatedwithcreateTemplate(TemplateRole=Enrollment_1N)intothegallery.

galleryDeleteID()isexecutedoneormoretimestoremoveatemplatefromthegallery.


G3 Search identifyTemplate()

Atemplateissearchedagainsttheenrollmentdatabase.


Accuracymetrics-TypeI+IIerrorrates.

342

343



4.3. API344

4.3.1. Interface345ThesoftwareundertestmustimplementtheinterfaceIdentInterfacebysubclassingthisclassandimplementing346eachmethodspecifiedtherein.347

C++codefragment Remarks1. Class IdentInterface 2. {

public:

3. static std::shared_ptr<IdentInterface> getImplementation(); FactorymethodtoreturnamanagedpointertotheIdentInterfaceobject.ThisfunctionisimplementedbythesubmittedlibraryandmustreturnamanagedpointertotheIdentInterfaceobject.

4. // Other functions to implement 5. };

Thereisoneclass(static)methoddeclaredinIdentInterface.getImplementation()whichmustalsobe348implemented.Thismethodreturnsasharedpointertotheobjectoftheinterfacetype,aninstantiationofthe349implementationclass.Atypicalimplementationofthismethodisalsoshownbelowasanexample.350

C++codefragment Remarks #include “frvt1N.h”

using namespace FRVT; NullImpl:: NullImpl () { } NullImpl::~ NullImpl () { } std::shared_ptr<IdentInterface> IdentInterface::getImplementation() { return std::make_shared<NullImpl>(); } // Other implemented functions

4.3.2. Initializationoftemplatecreation351Beforeanyfeatureextraction/templatecreationcallsaremade,theNISTtestharnesswillcalltheinitializationfunctionof352Table15.ThisfunctionwillbecalledBEFOREanycallstofork()aremade.353

Table15–Templatecreationinitialization354

Prototype ReturnStatusinitializeTemplateCreation( conststd::string&configDir, InputTemplateRolerole); Input

Description

Thisfunctioninitializestheimplementationundertestandsetsallneededparametersinpreparationfortemplatecreation.ThisfunctionwillbecalledN=1timesbytheNISTapplication,priortoparallelizingM>=1callstocreateTemplate()viafork(). Thisfunctionwillbecalledfromasingleprocess/thread.

InputParameters configDir Aread-onlydirectorycontaininganydeveloper-suppliedconfigurationparametersorrun-timedatafiles.

role AvaluefromtheTemplateRoleenumerationthatindicatestheintendedusageofthetemplatetobegenerated.Inthiscase,eitherEnrollment_1NorSearch_1N.

OutputParameters

None

ReturnValue SeeTable12forallvalidreturncodevalues.



4.3.3. TemplateCreation356AMultifaceisconvertedtoasingletemplateusingthefunctionofTable16.357

Table16–TemplateCreation/FeatureExtraction358

Prototypes ReturnStatuscreateTemplate( constMultiface&faces, InputTemplateRolerole, Inputstd::vector<uint8_t>&templ,std::vector<EyePair>&eyeCoordinates);

OutputOutput

Description TakesaMultifaceandoutputsaproprietarytemplateandassociatedeyecoordinates.Thevectortostorethetemplatewillbeinitiallyempty,anditisuptotheimplementationtopopulateitwiththeappropriatedata.

Note:Intheeventthatmorethanonefaceisdetectedinanimage,featuresshouldbeextractedfromtheforegroundface,thatis,thelargestfaceintheimage.

Forenrollmenttemplates(TemplateRole=Enrollment_1N):Ifthefunctionexecutescorrectly(i.e.returnsasuccessfulreturncode),thetemplatewillbeenrolledintoagallery.TheNISTcallingapplicationmaystoretheresultingtemplate,concatenatemanytemplates,andpasstheresulttotheenrollmentfinalizationfunction(seesection4.3.4).Theresultingtemplatemayalsobeinsertedimmediatelyintopreviouslyfinalizedgallery.Whentheimplementationfailstoproduceatemplate(i.e.returnsanon-successfulreturncode),itshallstillreturnablanktemplate(whichcanbezerobytesinlength).Thetemplatewillbeincludedintheenrollmentdatabase/manifestlikeallotherenrollmenttemplates,butisnotexpectedtocontainanyfeatureinformation.

IMPORTANT:NIST'sapplicationwritesthetemplatetodisk.Anydataneededduringsubsequentsearchesshouldbeincludedinthetemplate,orcreatedfromthetemplatesduringtheenrollmentfinalizationfunctionofsection4.3.4.

Foridentification/probetemplates(TemplateRole=Search_1N):TheNISTcallingapplicationmaycommitthetemplatetopermanentstorage,ormaykeepitonlyinmemory(thedeveloperimplementationdoesnotneedtoknow).Ifthefunctionreturnsanon-successfulreturnstatus,theoutputtemplatewillnotbeusedinsubsequentsearchoperations.

InputParameters

face InputMultifacerole Labeldescribingthetype/roleofthetemplatetobegenerated.Inthiscase,itwilleitherbe

Enrollment_1NorSearch_1N.OutputParameters

templ Theoutputtemplate.Theformatisentirelyunregulated.Thiswillbeanemptyvectorwhenpassedintothefunction,andtheimplementationcanresizeandpopulateitwiththeappropriatedata.

eyeCoordinates Thefunctionshallreturntheestimatedeyecentersfortheinputfaceimage.ReturnValue SeeTable12forallvalidreturncodevalues.

4.3.4. Finalization359Afteralltemplateshavebeencreated,thefunctionofTable17willbecalled.Thisfreezestheenrollmentdata.Afterthis360calltheenrollmentdatasetwillbeforeverread-only.361

Thefunctionallowstheimplementationtoconduct,forexample,statisticalprocessingofthefeaturedata,indexingand362datare-organization.Thefunctionmayalterthefilestructure.Itmayincreaseordecreasethesizeofthestoreddata.363Nooutputisexpectedfromthisfunction,exceptareturncode.364

Implementationsshallnotmovetheinputdata.Implementationsshallnotpointtotheinputdata.Implementations365shouldnotassumetheinputdatawillbereadableafterthecall.Implementationsmust,ataminimum,copytheinput366dataorotherwiseextractwhatisneededforsearch.367

Table17–Enrollmentfinalization368

Prototypes ReturnStatusfinalizeEnrollment( conststd::string&enrollmentDir, Inputconststd::string&edbName, Inputconststd::string&edbManifestName, InputGalleryTypegalleryType); Input



Description Thisfunctiontakesthenameofthetop-leveldirectorywheretheenrollmentdatabase(EDB)anditsmanifesthavebeenstored.Thesearedescribedinsection3.2.5.Theenrollmentdirectorypermissionswillberead+write.

Thefunctionsupportspost-enrollment,developer-optional,book-keepingoperations,statisticalprocessinganddatare-orderingforfastin-memorysearching.Thefunctionwillgenerallybecalledinaseparateprocessafteralltheenrollmentprocessesarecomplete.

Thisfunctionshouldbetolerantofbeingcalledtwoormoretimes.Secondandthirdinvocationsshouldprobablydonothing.

Thisfunctionwillbecalledfromasingleprocess/thread.

InputParameters

enrollmentDir Thetop-leveldirectoryinwhichenrollmentdatawasplaced.Thisvariableallowsanimplementationtolocateanyprivateinitializationdataitelectedtoplaceinthedirectory.

edbName Thenameofasinglefilecontainingconcatenatedtemplates,i.e.theEDBofsection3.2.5.Whilethefilewillhaveread-write-deletepermission,theimplementationshouldonlyalterthefileifitpreservesthenecessarycontent,inotherfilesforexample.Thefilemaybeopeneddirectly.Itisnotnecessarytoprependadirectoryname.ThisisaNIST-providedinput–implementersshallnotinternallyhard-codeorassumeanyvalues.

edbManifestName ThenameofasinglefilecontainingtheEDBmanifestofsection3.2.5.Thefilemaybeopeneddirectly.Itisnotnecessarytoprependadirectoryname.ThisisaNIST-providedinput–implementersshallnotinternallyhard-codeorassumeanyvalues.

galleryType AlabelfromTable10specifyingthecompositionofthegallery.

OutputParameters

None


369

4.3.5. SearchInitialization370ThefunctionofTable18willbecalledoncepriortooneormorecallsofthesearchingfunctionofTable19.Thefunction371mightsetstaticinternalvariablessothattheenrollmentdatabaseisavailabletothesubsequentidentificationsearches.372ThisfunctionwillbecalledBEFOREanycallstofork()aremade.373

Table18–Identificationinitialization374

Prototype ReturnStatusinitializeIdentification( conststring&configDir, Inputconststring&enrollmentDir); Input

Description ThisfunctionreadswhatevercontentispresentintheenrollmentDir,forexampleamanifestplacedtherebythefinalizeEnrollment()function.Thisfunctionwillbecalledfromasingleprocess/thread.

InputParameters configDir Aread-onlydirectorycontaininganydeveloper-suppliedconfigurationparametersorrun-timedatafiles.

enrollmentDir Theread-onlytop-leveldirectoryinwhichenrollmentdatawasplaced.ReturnValue SeeTable12forallvalidreturncodevalues.

4.3.6. Search375ThefunctionofTable19comparesaproprietaryidentificationtemplateagainsttheenrollmentdataandreturnsa376candidatelist.377

Table19–Identificationsearch378

Prototype ReturnStatusidentifyTemplate( conststd::vector<uint8_t>&idTemplate, Inputconstuint32_tcandidateListLength, Inputstd::vector<Candidate>&candidateList, Outputbool&decision); Output



Description

Thisfunctionsearchesatemplateagainsttheenrollmentset,andoutputsalistofcandidates.ThecandidateListvectorwillinitiallybeempty,andtheimplementationshallpopulatethevectorwithcandidateListLengthentries.

InputParameters idTemplate AtemplatefromcreateTemplate(TemplateRole=Search_1N)-Ifthevaluereturnedbythatfunctionwasnon-zerothecontentsofidTemplatewillnotbeusedandthisfunction(i.e.identifyTemplate)willnotbecalled.

candidateListLength ThenumberofcandidatesthesearchshouldreturnOutputParameters

candidateList Avectorcontaining"candidateListLength"objectsofcandidates.Thedatatypeisdefinedinsection3.2.6.Eachcandidateshallbepopulatedbytheimplementation.Thecandidatesshallappearindescendingorderofsimilarityscore-i.e.mostsimilarentriesappearfirst.

decision Abestguessatwhetherthereisamatewithintheenrollmentdatabase.Iftherewasamatefound,thisvalueshouldbesettotrue,Otherwise,false.ManysuchdecisionsallowasinglepointtobeplottedalongsideaDET.

ReturnValue SeeTable12forallvalidreturncodevalues.379

NOTE: Ordinarilythecallingapplicationwillsettheinputcandidatelistlengthtooperationallytypicalvalues,say0£L£380200,andL<<N.WewillmeasurethedependenceofsearchdurationonL.381

4.3.7. Galleryinsertionandremovaloftemplates382Thefunctionsofthissectioninsertanewtemplateinto,andremovesanexistingtemplatefrom,afinalizedgallery,383respectively.384

Table20–Insertionoftemplateintoagallery385

Prototype ReturnStatusgalleryInsertID( conststd::vector<uint8_t>&templ, Inputconststd::string&id); Input

Description

Thisfunctioninsertsatemplatewithanassociatedidintoanexistingfinalizedgallery.InvocationofthisfunctionwillalwaysbeprecededbyacalltoinitializeIdentification(),whichwillprovidethelocationofthefinalizedgallerytobeloadedintomemory.OneormorecallstoidentifyTemplate()maybemadeaftercallingthisfunction.

ThetemplateIDwillnotexistinthedatabasealready,soa1:Nduplicatesearchisnotnecessary.


InputParameters templ AtemplatecreatedviacreateTemplate(TemplateRole=Enrollment_1N)id Anidentifierassociatedwiththeenrollmenttemplate


Table21–Removaloftemplatefromagallery386

Prototype ReturnStatusgalleryDeleteID( conststd::string&id); Input

Description

Thisfunctiondeletesanexistingtemplatefromafinalizedgallery.InvocationofthisfunctionwillalwaysbeprecededbyacalltoinitializeIdentification(),whichwillprovidethelocationofthefinalizedgallery.OneormorecallstoidentifyTemplatemaybemadebeforeandaftercallingthisfunction.

ThetemplateIDwillexistinthedatabase.


InputParameters id AnidentifierassociatedwiththeenrollmenttemplateReturnValue SeeTable12forallvalidreturncodevalues.387

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