aqp (version 2.1.0)

rgb2munsell: sRGB to Munsell Color Conversion

Description

Convert sRGB color coordinates to the closest n Munsell chips in the munsell lookup table. This function will be replaced by col2Munsell() in aqp 2.1.

Usage

rgb2munsell(color, colorSpace = c("CIE2000", "LAB", "sRGB"), nClosest = 1)

Value

an (NA-padded) data.frame containing hue, value, chroma, and distance (dE00 when colorSpace = 'CIE2000', Euclidean distance otherwise) to nearest matching color.

Arguments

color

a data.frame or matrix object containing sRGB coordinates in the range of (0,1)

colorSpace

distance metric (colorspace) to use for finding the closest chip: CIE2000 is the most accurate but requires farver >= 2.0.3, Euclidean distance in CIELAB is a close second, while Euclidean distance in sRGB is not at all accurate and should only be used for demonstration purposes.

nClosest

number of closest Munsell colors to return (valid range is 1-20)

Author

D.E. Beaudette

References

http://ncss-tech.github.io/AQP/ http://www.brucelindbloom.com/index.html?ColorCalcHelp.html https://www.munsellcolourscienceforpainters.com/MunsellAndKubelkaMunkToolbox/MunsellAndKubelkaMunkToolbox.html http://www.cis.rit.edu/mcsl/online/munsell.php

Examples

# keep examples from using more than 2 cores
data.table::setDTthreads(Sys.getenv("OMP_THREAD_LIMIT", unset = 2))

# Munsell notation to sRGB triplets [0-1] 
color <- munsell2rgb(
  the_hue = c('10YR', '2.5YR', '5YR'), 
  the_value = c(3, 5, 2.5), 
  the_chroma = c(5, 6, 2), 
  return_triplets = TRUE
)

# result is a data.frame
color

# back-transform sRGB -> closest Munsell color
# sigma is the dE00 color contrast metric
rgb2munsell(color)