grDevices::convertColor has arguments 'from' and 'to' which can take on value
'XYZ'. Can someone confirm that 'XYZ' is the same as the CIE chromaticity
coordinates that are also sometimes refered to as 'xyY' in the literature? Or
are these the CIE tristimulus values? It looks to me like the
On 12/06/2013 2:45 PM, Bryan Hanson wrote:
grDevices::convertColor has arguments 'from' and 'to' which can take on value
'XYZ'. Can someone confirm that 'XYZ' is the same as the CIE chromaticity
coordinates that are also sometimes refered to as 'xyY' in the literature? Or
are these the CIE
Bryan Hanson hanson at depauw.edu writes:
grDevices::convertColor has arguments 'from' and 'to' which can
take on value 'XYZ'. Can
someone confirm
that 'XYZ' is the same as the CIE chromaticity coordinates
are also sometimes refered to
as 'xyY' in
the literature? Or are these the CIE
Ken, I followed your suggestion and perhaps I don't understand what to expect
from convertColor or maybe I'm not using it correctly. Consider the following
tests:
D65 - c(0.3127, 0.329, 0.3583) # D65 chromaticity coordinates
X - D65[1]*D65[3]/D65[2] # conversion per brucelindbloom.com
Y -
You seem to treating the input values as xyY when they should be XYZ
(case matters).
So, I would do something like this
D65 - c(0.3127, 0.329, 0.3583)
X - 100 * D65[1]
Y - 100 * D65[2]
Z - 100 * D65[3]
XYZ - data.frame(X = X, Y = Y, Z = Z)
convertColor(XYZ, from = XYZ, to = sRGB)
[,1]
Thank you Ken.
90% of my problem was missing the factor of 100. I was just inputing xyY as a
test, I wasn't sure whether the docs were being clear about nomenclature.
Speaking thereof, the D65 values used in the example: I thought they were
chromaticity coordinates, but apparently they are
If they sum to 1 then they are one and the same. Look at how
chromaticity coordinates are defined in terms of the tristimulus
values.
Quoting Bryan Hanson han...@depauw.edu:
Thank you Ken.
90% of my problem was missing the factor of 100. I was just
inputing xyY as a test, I wasn't sure
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