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Computer Music Researches in NTUEE. Shyh-Kang Jeng Department of Electrical Engineering/ Graduate Institute of Communication Engineering National Taiwan University. Research Areas of Shyh-Kang Jeng. Computer Music (JCMG) Agent Systems and Multimedia (JAMG)
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Computer Music Researchesin NTUEE Shyh-Kang Jeng Department of Electrical Engineering/ Graduate Institute of Communication Engineering National Taiwan University
Research Areas of Shyh-Kang Jeng • Computer Music (JCMG) • Agent Systems and Multimedia (JAMG) • Electromagnetic Theory and Applications (JEMG)
Outline • Sound Output and Separation • Sound Synthesis • Music Information Retrieval • Music Perception
Advantages of Interactive 3-D Sound System • Sound Localization • Spatial Impression • Fast Computer & DSP • It‘s very cheap!!!
What is HRTF ? • HRTF(Head Related Transfer Functions) 在自由聲場下,聲音傳遞至人耳耳道的轉移函數,為達成聽覺虛擬實境最重要的關鍵. • 3D Sound=HRTF*(Mono Sound Source) • Getting HRTF -- By Measurement or Simulation
仰角 0 ° 清大的 HRTF 麻省理工 HRTF 方位角 0 °和 可以辨認 :一人 可以辨認 :四人 180 °時的比較 不能辨認 :四人 不能辨認 :一人 方位角 0 °時 可以辨認 :四人 可以辨認 :四人 不能辨認 :一人 不能辨認 :一人 方位角 90 °時 均可辨認 均可辨認 方位角 180 °時 可以辨認 :四人 可以辨認 :四人 不能辨認 :一人 不能辨認 :一人 方位角 270 °時 均可辨認 均可辨認 HRTF的聽覺比較
10 unit : m 8 6 z - a x i s 4 2 0 10 8 6 4 2 0 -2 -4 10 8 6 -6 4 2 0 -8 -2 -4 -6 -10 -8 y - a x i s -10 x - a x i s Virtual Concert Hall
VIESS Architecture irc2 simulation Room environment HRTFL filter Sound source (*.wav file) RTF filter HRTFR filter
Weak Strong VIESS Demonstration Room environment irc2 simulation Sound Source (*.wav file) RTF filter Original
歌曲人聲消除 • 原音 軟體消音 自製消音
Outline • Sound Output and Separation • Sound Synthesis • Music Information Retrieval • Music Perception
Physical Modeling Synthesis • Synthesize sound of a musical instrument through computation based on its sound-generation model • The artificial instrument can have the same parameters as the real instrument • Expressivity of control is unlimited
吹管樂器樂音之物理模式合成 • Titanic
Outline • Sound Output and Separation • Sound Synthesis • Music Information Retrieval • Music Perception
Music Retrieval Service Key-Melody Notes Key-MelodySearching Unit MIDI Files The Best Match Desired Music MIDI Sequencer
Example of Melody Contour DS(1st Measure of “Moon River”) <MelodyContour> <Contour> 67 4 –1 –1 –1 –1 1</Contour> <Meter> <Numerator>3</Numerator> <Denominator>4<Denominator> <Meter> <Beat> 1 4 5 7 8 9 10</Beat> <MelodyContour>
Edit Distance Computation • p={0 0 -4 2 0 0 -3} q={0 0 0 2 2 -2}
Music Query System Prototype Put the note into the piano bar Choose what kinds of notes Message Board
Outline • Sound Output and Separation • Sound Synthesis • Music Information Retrieval • Music Perception
Rhythm Recognition Pitch Recognition Timbre Recognition Chord Recognition Time-frequency analysis Pattern recognition Integrated Recognition Model STFT Constant-Q Wavelet
Slope of the Attack Violin Flute AcousticPiano Trumpet String Ensembles AcousticGuitar
Results of Timbre Recognition Unit in Monophonic Environments Total Recognition rate = 80.56%
Results of Timbre Recognition Unit in Polyphonic Environments Total Recognition rate = 49.07%
Cochlea Cerebral Cortex Perception Neural Network Wavelet Transform Recognized Chords Models of Chord Classification
Transcription Example Original Transcription Result
2.5 2 Magnitude 1.5 1 0.5 0 0 200 400 600 800 1000 1200 1400 Frequency(Hz) 5 4.5 4 3.5 3 Magnitude 2.5 2 1.5 1 0.5 0 0 200 400 600 800 1000 1200 1400 Frequency (Hz) The Octave Problem
Digital audio signal Constant-Q transform Spectral peaks 64 Spectral peaks for every 64 samples Grouping Series G1 Series i Series C8 sustained or silent Onset/offset detection off on Series i Octave detector for series i Pitch(es) clear Pitch memory for series i Pitch Detection System
Octave Detection Example Original Test Results
Beat Tracking System • Off-line method • Input signal sampling rate : 8 kHz • Platform : MATLAB