This function creates colors of class “LAB”;
a subclass of the virtual “color” class.
Usage
LAB(L, A, B, names)
Arguments
L,A,B
these arguments give the L, A and B coordinates of
the colors. The values can be provided in separate L,
A and B vectors or in a three-column matrix
passed as L.
names
a vector of names for the colors (by default the
row names of L are used).
Details
The L, A and B values give the coordinates of
the colors in the CIE L*a*b* space.
This is a transformation of the 1931 CIE XYZ space which attempts to
produce perceptually based axes.
Luminance takes values between 0 and 100, and the other coordinates
take values between -100 and 100. The a and b coordinates
measure positions on green/red and blue/yellow axes.
Value
An object of class “LAB” which inherits from class “color.”
Author(s)
Ross Ihaka
See Also
RGB,
HSV,
XYZ,
LAB,
polarLAB,
LUV,
polarLUV.
Examples
## Show the LAB space
set.seed(1)
x <- RGB(runif(1000), runif(1000), runif(1000))
y <- as(x, "LAB")
head(x)
head(y)
plot(y)