cie: CIE colour spaces

Description

Calculates coordinates and colorimetric variables that represent reflectance spectra in either the CIEXYZ (1931), CIELAB (1971), or CIELCh (1971) colourspaces.

Usage

cie(vismodeldata, space = c("XYZ", "LAB", "LCh"))

Arguments

vismodeldata

(required) quantum catch color data. Can be either the result from vismodel() or independently calculated data (in the form of a data frame with three columns representing trichromatic viewer).

space

(required) Choice between XYZ (default), LAB, or LCh colour models.

Value

Object of class colspace containing:

X, Y, Z: Tristimulus values.
x, y, z: Cartesian coordinates, when using space = XYZ.
L, a, b: Lightness, L, and colour-opponent a (redness-greenness) and b (yellowness-blueness) values, in a Cartesian coordinate space. Returned when using space = LAB.
L, a, b, C, h: Lightness, L, colour-opponent a (redness-greenness) and b (yellowness-blueness) values, as well as chroma C and hue-angle h (degrees), the latter of which are cylindrical representations of a and b from the CIELAB model. Returned when using space = LCh.

References

Smith T, Guild J. (1932) The CIE colorimetric standards and their use. Transactions of the Optical Society, 33(3), 73-134.

Westland S, Ripamonti C, Cheung V. (2012). Computational colour science using MATLAB. John Wiley & Sons.

Stockman, A., & Sharpe, L. T. (2000). Spectral sensitivities of the middle- and long-wavelength sensitive cones derived from measurements in observers of known genotype. Vision Research, 40, 1711-1737.

CIE (2006). Fundamental chromaticity diagram with physiological axes. Parts 1 and 2. Technical Report 170-1. Vienna: Central Bureau of the Commission Internationale de l Eclairage.

Examples

Run this code

# NOT RUN {
data(flowers)
vis.flowers <- vismodel(flowers, visual = "cie10", illum = "D65", vonkries = TRUE, relative = FALSE)
flowers.ciexyz <- colspace(vis.flowers, space = "ciexyz")
flowers.cielab <- colspace(vis.flowers, space = "cielab")
flowers.cielch <- colspace(vis.flowers, space = "cielch")
# }