Introduction

The FourierDescriptors package provides methods for creating, manipulating and visualizing Fourier descriptors, a representational scheme used to describe closed planar contours. The images most easily described using Fourier descriptors are useful as stimuli for experiments in psychology and neuroscience.

Installation

This package is being submitted to CRAN. When it propagates through the mirrors, you can install it using a simple call to install.packages():

install.packages('FourierDescriptors')

For the time being, please install it using the included source package by downloading this repository and running:

R CMD INSTALL FourierDescriptors_*.tar.gz

Basic Usage Example

library('FourierDescriptors')

fd1 <- create.fourier.descriptor()
print(fd1)
plot(fd1)

fd2 <- random.fourier.descriptor(32, 2)
plot(fd2)

Please Note

• Only even-numbered frequencies can have non-zero amplitudes. Otherwise the described curve will not be closed.

Examples for Gaining Intuition about the Amplitude Spectrum

library('FourierDescriptors')

plot(create.fourier.descriptor(amplitude = c(0, 0, 0, 0)))

plot(create.fourier.descriptor(amplitude = c(0, 1, 0, 0)))

plot(create.fourier.descriptor(amplitude = c(0, 0, 0, 1)))

plot(create.fourier.descriptor(amplitude = c(0, 1, 0, 1)))

plot(random.fourier.descriptor(24,
                               non.zero.frequencies = 4,
                               generating.function = function() {runif(1)}),
     steps = 360 * 10)