soundecology (version 1.3.3)

ndsi: Normalized Difference Soundscape Index

Description

Normalized Difference Soundscape Index (NDSI) from REAL and Kasten, et al. 2012. The NDSI seeks to "estimate the level of anthropogenic disturbance on the soundscape by computing the ratio of human-generated (anthrophony) to biological (biophony) acoustic components found in field collected sound samples" (Kasten, et al. 2012).

Tested with Matlab code courtesy of S. Gage.

Usage

ndsi(soundfile, fft_w = 1024, anthro_min = 1000, anthro_max = 2000, 
	bio_min = 2000, bio_max = 11000)

Arguments

soundfile

an object of class Wave loaded with the function readWave of the tuneR package.

fft_w

FFT window size.

anthro_min

minimum value of the range of frequencies of the anthrophony.

anthro_max

maximum value of the range of frequencies of the anthrophony.

bio_min

minimum value of the range of frequencies of the biophony.

bio_max

maximum value of the range of frequencies of the biophony.

Value

Returns a list with one object per channel

ndsi_left

NDSI value for the left channel

ndsi_right

NDSI value for the right channel

biophony_left

value for the biophony for the left channel

anthrophony_left

value for the anthrophony for the left channel

biophony_right

value for the biophony for the right channel

anthrophony_right

value for the anthrophony for the right channel

Details

The bin size is determined as the difference between anthro_max and anthro_min, by default 1000 Hz.

References

Remote Environmental Assessment Laboratory. http://www.real.msu.edu

Kasten, Eric P., Stuart H. Gage, Jordan Fox, and Wooyeong Joo. 2012. The Remote Environmental Assessment Laboratory's Acoustic Library: An Archive for Studying Soundscape Ecology. Ecological Informatics 12: 50-67. doi: 10.1016/j.ecoinf.2012.08.001

Examples

# NOT RUN {
	data(tropicalsound)
	NDSI <- ndsi(tropicalsound)
	print(NDSI$ndsi_left)
	
	summary(NDSI)
	
# }