最新Using Blackboard Systems for Polyphonic Transcription教学讲义PPT.ppt

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1、UsingBlackboardSystemsforPolyphonicTranscriptionOutlineIntrotopolyphonictranscriptionIntrotoblackboardsystemsKeithMartin’sworkKunioKashino’sworkRecentcontributionsConclusionPolyphonicTranscriptionRepresentanaudiosignalasascoreMustsegregatenotesbelongingtodifferentvoicesProblems:variatio

2、nsoftimbrewithinavoice,voicecrossing,identificationofcorrectoctaveNosuccessfulgeneralpurposesystemtodateBlackboardSystems“Blackboard”isacentraldataspaceUsuallyarrangedinhierarchysothatinputisatlowestlevelandoutputisathighest“Experts”arecalled“knowledgesources”KSsgenerallyconsistofasetof

3、heuristicsandapreconditionwhosesatisfactionresultsinahypothesisthatiswrittenonblackboardEachKSformshypothesesbasedoninformationfromfrontendofsystemandhypothesespresentedbyotherKSsBlackboardSystemsProblemissolvedwhenallKSsaresatisfiedwithallhypothesesonblackboardtowithinagivenmarginoferr

4、orEliminatesneedforglobalcontrolmoduleEachKScanbeeasilyupdatedandnewKSscanbeaddedwithlittledifficultyCombinestop-downandbottom-upprocessingBlackboardSystemsMusichasanaturallyhierarchalstructurethatlendsitselfwelltoblackboardsystemsAllowintegrationofdifferenttypesofexpertise:signalproces

5、singKSsatlowlevelhumanperceptionKSsatmiddlelevelmusicalknowledgeKSsatupperlevelBlackboardSystemsLimitation:givingupperlevelKSstoomuchspecializedknowledgeandinfluencelimitsgeneralityoftranscriptionsystemsIdealsystemwouldnotuseknowledgeabovethelevelofhumanperceptionandthemostrudimentaryun

6、derstandingofmusicCurrenttrendistoincreasesignificanceofupper-levelmusicalKSsinordertoincreasesuccessrateKeithMartin(1996a)“ABlackboardSystemforAutomaticTranscriptionofSimplePolyphonicMusic”Usedablackboardsystemtotranscribeafour-voiceBachchoralewithappropriatesegregationofvoicesLimitedi

7、nputsignaltosynthesizedpianoperformancesGavesystemonlyrudimentarymusicalknowledge,althoughchoiceofBachchoraleallowedtheuseofgenerallyunacceptableassumptionsbylowerlevelKSsKeithMartin(1996a)Front-endsystemusedshort-timeFouriertransformoninputsignalEquivalenttoafilterbankthatisag