Momocs (version 1.0.0)

rfourier_i: Inverse radii variation Fourier transform

Description

rfourier_i uses the inverse radii variation transformation to calculate a shape, when given a list with Fourier coefficients, typically obtained computed with rfourier.

Usage

rfourier_i(rf, nb.h, nb.pts = 120)

Arguments

rf

A list with ao, an and bn components, typically as returned by rfourier.

nb.h

integer. The number of harmonics to calculate/use.

nb.pts

integer. The number of points to calculate.

Value

A list with components:

x

vector of x-coordinates.

y

vector of y-coordinates.

angle

vector of angles used.

r

vector of radii calculated.

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_shape, rfourier

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)