specprop: Spectral properties

Description

This function returns a list of statistical properties of a frequency spectrum.

Usage

specprop(spec, f=NULL,
str = FALSE, flim=NULL, mel=FALSE,
plot = FALSE, type = "l", xlab=NULL, ylab = NULL,
col.mode = 2, col.quartiles = 4, ...)

Value

A list of 15 values is returned

mean: mean frequency (see mean)
sd: standard deviation of the mean (see sd)
sem: standard error of the mean
median: median frequency (see median)
mode: mode frequency, i.e. the dominant frequency
Q25: first quartile (see quantile)
Q75: third quartile (see quantile)
IQR: interquartile range (see IQR)
cent: centroid, see note
skewness: skewness, a measure of asymmetry, see note
kurtosis: kurtosis, a measure of peakedness, see note
sfm: spectral flatness measure (see sfm)
sh: spectral entropy (see sh)
prec: frequency precision of the spectrum

Arguments

spec: a data set resulting of a spectral analysis obtained with spec or meanspec (not in dB).
f: sampling frequency of spec (in Hz).
str: logical, if TRUE returns the results in a structured table.
flim: a vector of length 2 to specifgy the frequency limits of the analysis (in kHz)
mel: a logical, if TRUE the (htk-)mel scale is used.
plot: if 1 returns the spectrum , if 2 returns the cumulative spectrum, both of them with the first quartile, the third quartile, the median and the mode plotted (by default FALSE).
type: if plot is TRUE, type of plot that should be drawn. See plot for details (by default "l" for lines).
xlab: label of the x axis.
ylab: label of the y axis.
col.mode: colour of the mode segments (by default blue).
col.quartiles: colour of the quartiles segments (by default red).
...: other arguments to be passed to plot

Author

Jerome Sueur and Caroline Simonis, and a patch by Jesse Ross (Dec. 2012)

Details

The spectrum is converted in a probability mass function (PMF).
If a selected value has to be selected with $, the argument str has to be set to FALSE.

Examples

Run this code

data(orni)
a<-meanspec(orni,f=22050,plot=FALSE)
specprop(a,f=22050)
# to get a single measure of the list
specprop(a,f=22050)$mode
# to get the results structured
specprop(a,f=22050,str=TRUE)
# to limit the analysis between 4 and 6 kHz
specprop(a,f=22050,flim=c(4,6),str=TRUE)
# plots
specprop(a,f=22050,plot=1)
specprop(a,f=22050,plot=2)
# (htk-)mel scale
require(tuneR)
mel <- melfcc(orni, nbands = 256, dcttype = "t3", fbtype = "htkmel", spec_out=TRUE)
melspec.mean <- apply(mel$aspectrum, MARGIN=2, FUN=mean)
specprop(melspec.mean, f=22050, mel=TRUE)
# be aware that flim is always given in kHz even if mel=TRUE
specprop(melspec.mean, f=22050, flim=c(4,6), mel=TRUE, plot=TRUE)

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