maad.features.temporal_activity
- maad.features.temporal_activity(s, dB_threshold=3, mode='fast', Nt=512)[source]
Compute the acoustic activity index in temporal domain.
Acoustic activity corresponds to the portion of the waveform above a threshold [1] [2]
Three values are computed with this function:
ACTfract : proportion (fraction) of points above the threshold
ACTcount : number of points above the threshold
ACTmean : mean value (in dB) of the portion of the signal above the threhold
- Parameters:
- s1D array of floats
audio to process (wav)
- dB_thresholdscalar, optional, default is 3dB
data >Threshold is considered to be an activity
- modestr, optional, default is “fast”
Select the mode to compute the envelope of the audio waveform
- “fast”The sound is first divided into frames (2d) using the
function _wave2timeframes(s), then the max of each frame gives a good approximation of the envelope.
- “Hilbert”estimation of the envelope from the Hilbert transform.
The method is slow
- Ntinteger, optional, default is 512
Size of each frame. The largest, the highest is the approximation.
- Returns:
- ACTfract :ndarray of scalars
proportion (fraction) of points above the threshold for each frequency bin
- ACTcount: ndarray of scalars
number of points above the threshold for each frequency bin
- ACTmean: scalar
mean value (in dB) of the portion of the signal above the threhold
References
[1]Towsey, Michael (2013), Noise Removal from Waveforms and Spectrograms Derived from Natural Recordings of the Environment. Queensland University of Technology, Brisbane. https://eprints.qut.edu.au/61399/4/61399.pdf
[2]QUT : https://github.com/QutEcoacoustics/audio-analysis. Michael Towsey, Anthony Truskinger, Mark Cottman-Fields, & Paul Roe. (2018, March 5). Ecoacoustics Audio Analysis Software v18.03.0.41 (Version v18.03.0.41). Zenodo. http://doi.org/10.5281/zenodo.1188744
Examples
>>> import maad >>> s, fs = maad.sound.load('../data/spinetail.wav') >>> ACTfract, ACTcount, ACTmean = maad.features.temporal_activity (s, 6) >>> print('ACTfract: %2.2f / ACTcount: %2.0f / ACTmean: %2.2f' % (ACTfract, ACTcount, ACTmean)) ACTfract: 0.37 / ACTcount: 620 / ACTmean: 24.41