Automated Transcription of Polyphonic Piano Music A Brief Literature Review

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Automated Transcription of Polyphonic Piano
MusicA Brief Literature Review

• Catherine Lai
• MUMT-611 MIR
• February 17, 2005

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Outline of Presentation

• Introduction
• transcription of polyphonic music
• targeted on specific instruments
• Current state-of-the-art various approaches
• Recent published piano transcription systems
• Dixon, 2000
• Raphael, 2002
• Monti and Sandler, 2002
• Marolt, 2004
• Discussion and Conclusion
• Links to examples of transcription of piano music
  recordings
• Bibliography

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Introduction

• Transcription of polyphonic music
• acoustical waveform --gt parametric representation
• extract pitches, starting times, durations
• First attempt by Moorer, 1975
• note range limitation
• two voices constraint
• Martin, 1996
• piano transcription system up to four voices
• chorale style of J.S. Bach (long durations with
  block chords)
• Future systems tackled limitations
• targeted system on specific instruments
• Focus of this literature review
• automated transcription of polyphonic piano music

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Current State-of-the-Art Various Approaches

• Automated transcription of polyphonic piano music
• input audio files containing polyphonic piano
  music
• output MIDI representing pitch, timing, volume
• Simon Dixon, 2000. On the Computer Recognition
  of Solo Piano Music
• standard SP, adaptive peak-picking, pattern
  matching
• Christopher Raphael, 2002. Automatic
  Transcription of Piano Music
• HMM
• Monti and Sandler, 2002. Automatic Polyphonic
  Piano Note Extraction Using Fussy Logic in a
  Blackboard System
• blackboard algorithm
• Matija Marolt, 2004 A connectionist approach to
  automatic transcription of polyphonic music
• neural network models

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Published Piano Transcription SystemSimon
Dixon, 2000. On the computer recognition of solo
piano music standardized SP approach

• 1st processing stage
• low-filtering --gt down-sampling signal (12kHz)
• Time-frequency representation
• STFT --gt power spectrum --gt spectral peak
  extraction (local maxima gt threshold, adaptive
  peak-picking algorithm)
• frequency tracks --gt grouping partials --gt
  musical notes
• Evaluation 13 Mozart piano sonata performed by a
  concert pianist
• Bösendorfer SE290 computer-monitored piano --gt
  MIDI
• Results Nno. correctly i.d. notes FPno. note
  reported not played FNno. notes played not
  reported by system incorrectly I.d. note FP
  and FN
• score N/(FP FN N)
• recognition accuracy of 70-80
• Future development
• accuracy of dynamic and offset times

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Published Piano Transcription SystemChristopher
Raphael, 2002. Automatic transcription of piano
musicHMM

• HMM- trained likelihood model
• statistical pattern recognition and machine
  learning for structures
• Process
• segment signal to frames extract features
  (vector) from frames assign label for content
  description
• Precise vector features
• total energy (play or silent)
• local burstiness (attack, steady behavior)
• pitch configuration
• Label
• sound pitches collection and re-articulation
  (attack, sustain, rest)
• Model setup
• hidden process (label process) observable
  process (feature vector)
• generate reasonable hypotheses for each frame and
  construct search graph of the hypotheses

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Published Piano Transcription SystemChristopher
Raphael, 2002. Automatic transcription of piano
musicHMM

• Experiment
• Mozart piano sonata
• limitations on range (c two octave below middle c
  to the f to two and a half octave above middle c)
• number of voices 4 or less
• Evaluation
• borrowed from speech evaluation of Word Error
  Recognition Rate
• Error Rate 100 (Insertions Deletions
  Substitutions) / (Total Words in Truth Sentence)
• preliminary results have a Note Error Rate of
  39
• 184 substitutions, 241 deletions, 108 insertions
  out of 1360 notes
• Future improvement
• simple additions may yield better results
• likelihood of chord sequence
• informative note onsets acoustic cues

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Published Piano Transcription System Monti and
Sandler 2002. Automatic polyphonic piano note
extraction using fussy logic in a blackboard
system Blackboard algorithm

• Implementation
• Polyphonic Note Recognition using a Fuzzy
  Inference System (FIS) as part of the Knowledge
  Sources (KSs) in a Blackboard system
• Blackboard model arrangement
• hierarchy of data abstraction level
• KSs dictate advancement and is
• activated by Scheduler
• FIS
• take spectral peaks not selected
• create new Note Candidates
• evaluate Candidate by features
• fundamental of note
• harmonic rate
• difference bt max peak in
• spectrum and Candidates fundamental energy

Blackboard system (Monti and Sandler, 2002)
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Published Piano Transcription System Monti and
Sandler 2002. Automatic polyphonic piano note
extraction using fussy logic in a blackboard
system Blackboard algorithm

• Evaluation
• 14 piano pieces by various composer including
  Beethoven, Mozart, Debussy, Ravel, and Scarlatti
• Results Ncorrectly i.d. notes FPnote not
  played FNnotes not reported by sys
• score N/(FP FN N) Dixons
• detection success rate 45 correct
• 75 correctly detected note / total transcribed
  notes

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Published Piano Transcription System Matija
Marolt, 2004 A connectionist approach to
automatic transcription of polyphonic piano
music. Neural networks approach

• New model based on networks of adaptive
  oscillators was proposed and implemented in SONIC
  to partial tracking and note recognition

5.adaptive oscillators try to synchronize to
signals in output freq channels of the auditory
model by adjusting its phase and frequency 6.
When synchronized to the output freq indicate the
freq is periodic and a partial with feq sim to
filter present
1. acoustical waveform --gttime-feq space with an
auditory model 2. auditory model output set of
freq channel 3. periodicity in frequency
channels is related to pitch perception 4. use
adaptive oscillators to calculate periodicity in
frequency channels
76 neural networks others tested multilayer
perception, radial basis function, etc.
Marolt, 2004
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Published Piano Transcription System Matija
Marolt, 2004 A connectionist approach to
automatic transcription of polyphonic piano
music. Neural networks approach

• Evaluation
• tested on synthesized and real recordings of
  various genre
• Results
• synthesized recoding around 90 of all notes
• real recording results not as good (not
  available)
• most common error (gt 50) octaves and rapidly
  played notes (e.g.arpeggios, trills)
• greatest challenge very expressive playing
• Chopins Nocturnes
• quiet and almost inaudible left hand
• Further Development
• detecting repeated notes

Marolt, 2004
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Discussion and Conclusion

• Various approaches proposed
• standard S.P. techniques HMM blackboard
  algorithm neural networks
• Common mistakes
• octave, rapid passages, and quiet notes
• Difficulties
• lack standard set of test examples
• evaluation function
• various constraints and formula -- gt comparison
  difficult

Piano transcription system Performance results
Dixon 70-80 correct
SONIC 80-95 correct
Raphael 39 wrong
Monti and Sandler 74 correct
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Links to examples of transcription of piano music
recordings

• http//lgm.fri.uni-lj.si/matic/SONIC.html
  (Marolt)
• http//www.ai.univie.ac.at/simon/ (Dixon)

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Bibliography

• Dixon, S. 2000. On the Computer Recognition of
  Solo Piano Music. Australasian Computer Music
  Conference. 31-7.
• Marolt, M. 2004. A connectionist approach to
  automatic transcription of polyphonic piano
  music. IEEE Transactions on Multimedia 6, no. 3
  (June) 439-49.
• Martin, K. 1996. A blackboard system for
  automatic transcription of simple polyphonic
  music. MIT Media Laboratory Perceptual Computing
  Section Technical Report No. 385.
• Montipi, G, and M. Sandler. 2002. Automatic
  Polyphonic Piano Note Extraction Using Fuzzy
  Logic in a Blackboard System. Proceedings of the
  International Conference on Digital Audio
  Effects. 39-44.
• Moorer, J. 1975. On the segmentation and analysis
  of continuous musical sound by digital computer.
  Ph.D. thesis, Stanford University, CCRMA.
• Raphael, C. 2002. Automatic Transcription of
  Piano Music. Proceedings of the International
  Conference on Music Information Retrieval.

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