getKMeanColors {colordistance}

Fit pixels to clusters using KMeans clustering

Description

Uses KMeans clustering to determine color clusters that minimize the sum of distances between pixels and their assigned clusters. Useful for parsing common color motifs in an object.

Usage

getKMeanColors(
  path,
  n = 10,
  sample.size = 20000,
  plotting = TRUE,
  lower = c(0, 0.55, 0),
  upper = c(0.24, 1, 0.24),
  iter.max = 50,
  nstart = 5,
  return.clust = TRUE,
  color.space = "rgb",
  from = "sRGB",
  ref.white
)

Arguments

path

Path to an image (JPG or PNG).

n

Number of KMeans clusters to fit. Unlike getImageHist, this represents the actual final number of bins, rather than the number of breaks in each channel.

sample.size

Number of pixels to be randomly sampled from filtered pixel array for performing fit. If set to FALSE, all pixels are fit, but this can be time-consuming, especially for large images.

plotting

Logical. Should the results of the KMeans fit (original image + histogram of colors and bin sizes) be plotted?

lower

RGB triplet specifying the lower bounds for background pixels. Default upper and lower bounds are set to values that work well for a bright green background (RGB [0, 1, 0]).

upper

RGB triplet specifying the upper bounds for background pixels. Default upper and lower bounds are set to values that work well for a bright green background (RGB [0, 1, 0]). Determining these bounds may take some trial and error, but the following bounds may work for certain common background colors:

• Black: lower=c(0, 0, 0); upper=c(0.1, 0.1, 0.1)

• White: lower=c(0.8, 0.8, 0.8); upper=c(1, 1, 1)

• Green: lower=c(0, 0.55, 0); upper=c(0.24, 1, 0.24)

• Blue: lower=c(0, 0, 0.55); upper=c(0.24, 0.24, 1)

If no background filtering is needed, set bounds to some non-numeric value (NULL, FALSE, "off", etc); any non-numeric value is interpreted as NULL.

iter.max

Inherited from kmeans. The maximum number of iterations allowed.

nstart

Inherited from kmeans. How many random sets should be chosen?

return.clust

Logical. Should clusters be returned? If FALSE, results are plotted but not returned.

color.space

The color space ("rgb", "hsv", or "lab") in which to cluster pixels.

from

Display color space of image if clustering in CIE Lab space, probably either "sRGB" or "Apple RGB", depending on your computer.

ref.white

The reference white passed to convertColorSpace; must be specified if using CIE Lab space. See convertColorSpace.

Value

A kmeans fit object.

Examples

colordistance::getKMeanColors(system.file("extdata",
"Heliconius/Heliconius_B/Heliconius_07.jpeg", package="colordistance"), n=3,
return.clust=FALSE, lower=rep(0.8, 3), upper=rep(1, 3))