seewave (version 1.6.4)

diffenv: Difference between two amplitude envelopes

Description

This function estimates the surface difference between two amplitude envelopes.

Usage

diffenv(wave1, wave2, f, envt = "hil", msmooth = NULL, ksmooth = NULL,
plot = FALSE, lty1 = 1, lty2 = 2, col1 = 2, col2 = 4, cold = 8,
xlab = "Time (s)", ylab = "Amplitude", ylim = NULL, legend = TRUE, ...)

Value

• The difference is returned. This value is without unit. When plot is TRUE, both envelopes and their difference surface are plotted on the same graph.

Details

Envelopes of both waves are first transformed as probability mass functions (PMF). Envelope difference is then computed according to: $$D = \frac{\sum{|env1-env2|}}{2}, with D \in [0,1].$$

References

Sueur, J., Pavoine, S., Hamerlynck, O. & Duvail, S. (2008) - Rapid acoustic survey for biodiversity appraisal. PLoS ONE, 3(12): e4065.

See Also

env, corenv, diffspec, diffwave

Examples

data(tico) ; tico <- tico@left
data(orni) ; orni <- orni@left
# selection in tico of two waves with similar duration
tico2<-tico[1:length(orni)]
diffenv(tico2,orni,f=22050,plot=TRUE)
# smoothing the envelope gives a better graph but slightly changes the result
diffenv(tico2,orni,f=22050,msmooth=c(20,0),plot=TRUE)