maad.features.spectral_cover

maad.features.spectral_cover(Sxx, fn, dB_threshold=3, flim_LF=(0, 1000), flim_MF=(1000, 10000), flim_HF=(10000, 20000))[source]

Compute the proportion (cover) of the spectrogram above a threshold for three bandwidths : low frequency band (LF), medium frequency band (MF) and high frequency band (HF) [1] [2].

Parameters:

Sxx2D array of floats: Spectrogram 2D in dB. Usually, better to work with spectrogram without stationnary noise in order to measure only acoustic activity above the background noise
fn1d ndarray of floats: frequency vector
dB_thresholdscalar, optional, default is 3dB: data >Threshold is considered to be an activity
flim_LFtupple, optional, default is (0,1000): Low frequency band in Hz
flim_MFtupple, optional, default is (1000,10000): mid frequency band in Hz
flim_HFtupple, optional, default is (10000,20000): high frequency band in Hz

Returns:

LFC :scalar: Proportion of the LF bandwidth of the spectrogram with activity above the threshold
MFC: scalar: Proportion of the MF bandwidth of the spectrogram with activity above the threshold
HFC: scalar: Proportion of the HF bandwidth of the spectrogram with activity above the threshold

References

[1]

TOWSEY, Michael W. The calculation of acoustic indices derived from long-duration recordings of the natural environment. 2017. https://eprints.qut.edu.au/110634/1/QUTePrints110634_TechReport_Towsey2017August_AcousticIndices%20v3.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/cold_forest_daylight.wav')
>>> Sxx_power, tn, fn, ext = maad.sound.spectrogram (s, fs)  
>>> Sxx_noNoise= maad.sound.median_equalizer(Sxx_power, display=True, extent=ext) 
>>> Sxx_dB_noNoise = maad.util.power2dB(Sxx_noNoise)
>>> LFC, MFC, HFC = maad.features.spectral_cover(Sxx_dB_noNoise, fn) 
>>> print('LFC: %2.2f / MFC: %2.2f / HFC: %2.2f' % (LFC, MFC, HFC)) 
LFC: 0.15 / MFC: 0.19 / HFC: 0.13