pliman (version 2.1.0)

efourier_error: Erros between the original and reconstructed outline

Description

Computes the sum of squared distances between the original data and reconstructed outline. It allows examining reconstructed outlines with the addition of successive contributing harmonics indicated in the argument nharm.

Usage

efourier_error(
  x,
  nharm = NULL,
  type = c("error", "outline", "deviations"),
  plot = TRUE,
  ncol = NULL,
  nrow = NULL
)

Value

A list with the objects:

• dev_points A list with the deviations (distances) from original and predicted outline for each pixel of the outline.

• data.frame object with the minimum, maximum and average deviations (based on the outline points).

If x is an object of class efourier_lst, a list will be returned.

Arguments

x

An object computed with efourier().

nharm

An integer or vector of integers indicating the number of harmonics to use. If not specified the number of harmonics used in x is used.

type

The type of plot to produce. By default, a line plot with the sum of squared distances (y-axis) and the number of harmonics (x-axis) is produced. If type = "outline" is used, a plot with the original polygon and the constructed outline is produced. If type = "deviations" is used, a plot with the deviations from the original outline and reconstructed outline (y-axis) and points along the outline (x-axis) is produced.

plot

A logical to inform if a plot should be produced. Defaults to TRUE.

ncol, nrow

The number of rows or columns in the plot grid. Defaults to NULL, i.e., a square grid is produced.

Examples

library(pliman)
ef <-
  contours[[1]] |>
  efourier(nharm = 30)

efourier_error(ef)

efourier_error(ef,
               nharm = 30,
               type = "outline")

efourier_error(ef,
               nharm = c(1, 4, 20),
               type = "deviations")