col2Munsell: Convert colors into Munsell Notation

In ncss-tech/aqp: Algorithms for Quantitative Pedology

Convert colors into Munsell Notation

Description

Lookup the n closest Munsell chips from the munsell lookup table from various color notations. This function replaces rgb2munsell().

Usage

col2Munsell(col, space = c("sRGB", "CIELAB"), nClosest = 1)

Arguments

col	character vector of colors, data.frame or matrix of color coordinates in sRGB or CIELAB color space
space	character, one of sRGB or CIELAB, defines the input color system
nClosest	integer, number of closest Munsell colors to return (valid range is 1-20)

Value

an (NA-padded) data.frame containing hue, value, chroma, and CIE delta-E 2000 color contrast metric between source and nearest matching color(s).

Note

This function is fully vectorized and will pad output with NA-records when NA are present in color.

Author(s)

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

# vector of named R colors
col2Munsell(c('red', 'green', 'blue'))

# sRGB matrix in the range of 0-255
col2Munsell(cbind(255, 0, 0))

# sRGB matrix in the range of 0-1
col2Munsell(cbind(1, 0, 0))

# 10YR 5/6 in CIELAB
col2Munsell(
  cbind(51.4337, 9.917916, 38.6889), 
  space = 'CIELAB'
)

# 2.5YR 6/8 in hex notation
col2Munsell("#D18158FF")

# 7.5YR 8/1 in sRGB {0, 1}
col2Munsell(
  cbind(0.8240707, 0.7856834, 0.7541048)
)

# 7.5YR 8/1 in sRGB {0, 255}
col2Munsell(
  cbind(0.8240707, 0.7856834, 0.7541048) * 255
)

# multple colors in CIELAB
col2Munsell(
  parseMunsell(c('10BG 6/6', '2.5YR 4/6'), returnLAB = TRUE),
  space = 'CIELAB'
)

# data.frame input
col2Munsell(
  data.frame(r = 1, g = 0, b = 0),
  space = 'sRGB'
)

# 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 of sRGB {0, 1}
color

# back-transform sRGB -> closest Munsell color
# sigma is the dE00 color contrast metric
col2Munsell(color, space = 'sRGB')

ncss-tech/aqp documentation built on April 19, 2024, 5:38 p.m.