6-3 EPD in Frequency Domain (IGW鴘榭)

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(請注意：中文版本並未隨英文版本同步更新！)

有聲音訊在頻譜上會有重複的諧波結構，因此我們也可以使用頻譜的變異數或是 Entropy 來進行端點偵測，相關論文及投影片請見此連結。

（待續） Here are two examples to show spectra of audio signals:

Example 1: epdShowSpec01.m

waveFile='SingaporeIsAFinePlace.wav'; au=myAudioRead(waveFile); time=(1:length(au.signal))/au.fs; subplot(211); plot(time, au.signal); axis([min(time), max(time), -1, 1]); ylabel('Amplitude'); title(waveFile); subplot(212); frameSize=256; overlap=frameSize/2; [S,F,T]=spectrogram(au.signal, frameSize, overlap, 4*frameSize, au.fs); magSpec=abs(S); specgram=log(magSpec); imagesc(T, F, specgram); axis xy xlabel('Time (sec)'); ylabel('Freq (Hz)'); audioPlayButton(au); colormap jet;

Example 2: epdShowSpec02.m

waveFile='noisy4epd.wav'; au=myAudioRead(waveFile); time=(1:length(au.signal))/au.fs; subplot(211); plot(time, au.signal); axis([min(time), max(time), -1, 1]); ylabel('Amplitude'); title(waveFile); subplot(212); frameSize=256; overlap=frameSize/2; [S,F,T]=spectrogram(au.signal, frameSize, overlap, 4*frameSize, au.fs); magSpec=abs(S); specgram=log(magSpec); imagesc(T, F, specgram); axis xy xlabel('Time (sec)'); ylabel('Freq (Hz)'); audioPlayButton(au); colormap jet;

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Audio Signal Processing and Recognition (音訊處理與辨識)