seewave (version 1.4.1)

diffspec: Surface difference between two frequency spectra

Description

This function calculates the difference between the surfaces of two frequency spectra.

Usage

diffspec(spec1, spec2, f, dB = FALSE, plot = FALSE, type = "l",
lty1 = 1, lty2 = 2, col1 = 2, col2 = 4, cold = 8,
flab = "Frequency (kHz)", alab = "Amplitude",
flim = c(0, f/2000), alim = c(0, 1.1), ...)

Arguments

spec1

a first data set resulting of a spectral analysis obtained with spec or meanspec (not in dB).

spec2

a second data set resulting of a spectral analysis obtained with spec or meanspec (not in dB).

f

sampling frequency of waves used to obtain spec1 and spec2 (in Hz).

dB

logical, if TRUE return the spectra and their surface difference in dB (by default FALSE).

plot

logical, if TRUE plots both spectra and their surface difference (by default FALSE).

type

plot type, see plot.

lty1

line type of spec1 if type="l".

lty2

line type of spec2 if type="l".

col1

colour of spec1.

col2

colour of spec2.

cold

colour of the surface difference.

flab

title of the frequency axis.

alab

title of the amplitude axis.

flim

the range of frequency values.

alim

range of amplitude axis.

...

other plot graphical parameters.

Value

• The surface difference is returned. This value is without unit, spectra being scaled between 0 and 1. If dB is TRUE, the same value is returned in dB. When plot is TRUE, both spectra and their difference surface are plotted on the same graph.

Details

This method can be used as a relative distance estimation between different spectra.

See Also

spec, meanspec, corspec

Examples

a<-noise(f=8000,d=1)
b<-synth(f=8000,d=1,cf=2000)
c<-synth(f=8000,d=1,cf=1000)
speca<-spec(a,f=8000,wl=512,at=0.5,plot=FALSE)
specb<-spec(b,f=8000,wl=512,at=0.5,plot=FALSE)
specc<-spec(c,f=8000,wl=512,at=0.5,plot=FALSE)
diffspec(speca,speca,f=8000)
#[1] 0 => similar spectra of course !
diffspec(speca,specb,f=8000)
#[1] 85.40181 => different spectra
diffspec(speca,specc,f=8000,plot=TRUE)
#[1] 0.1139283