Momocs (version 1.0.0)

rfourier: Radii variation Fourier transform

Description

rfourier computes radii variation Fourier analysis from a matrix or a list of coordinates.

Usage

rfourier(x, ...)
"rfourier"(x, nb.h, smooth.it = 0, norm = FALSE, verbose = TRUE, ...)
"rfourier"(x, nb.h = 40, smooth.it = 0, norm = TRUE, verbose = TRUE, ...)

Arguments

x

A list or matrix of coordinates or an Out object

...

useless here

nb.h

integer. The number of harmonics to use. If missing 99pc harmonic power is used.

smooth.it

integer. The number of smoothing iterations to perform.

norm

logical. Whether to scale the outlines so that the mean length of the radii used equals 1.

verbose

logical. Whether to display diagnosis messages.

Value

A list with following components:

• an vector of $a_{1->n}$ harmonic coefficients
• bn vector of $b_{1->n}$ harmonic coefficients
• ao ao harmonic coefficient.
• r vector of radii lengths.

Details

see the JSS paper for the maths behind.

References

Claude, J. (2008) Morphometrics with R, Use R! series, Springer 316 pp.

See Also

Other rfourier: rfourier_i, rfourier_shape

Examples

data(bot)
coo <- coo_center(bot[1]) # centering is almost mandatory for rfourier family
coo_plot(coo)
rf  <- rfourier(coo, 12)
rf
rfi <- rfourier_i(rf)
coo_draw(rfi, border='red', col=NA)