colorSpec is an R package providing an S3 class with methods for color spectra. It supports the standard calculations with spectral properties of light sources, materials, cameras, eyes, scanners, etc. And it works well with the more general action spectra.
When a spectrum is contructed, a quantity
is required,
though it can be changed after contruction.
The colorSpec quantities are typically not the same as the SI quantities;
they are more general.
There are 14 quantities, which then defined the 4 basic spectrum types
,
as given in this table from the User Guide.
colorSpectype
quantity
metric
comments
examples(objects, files, functions)
light
energy
radiometric
radiometric quantities are conventional in colorimetry
D65.1nmpos1-20x.scopeBlueFlame.txt
photons
actinometric
for color calculations, actinometric units are automatically converted to radiometric
F96T12 Airam-GR8E.txtresponsivity.light
energy->electrical
radiometric
RGB camera response
Flea2.RGBRed-Epic-Dragon.txt
energy->neural
eye response
xyz1931.1nmluminsivity.1nmOsmia-rufa.txt
energy->action
examples are erythemal action, melatonin suppression, etc.
erythemalSpectrum()
photons->electrical
actinometric
silicon sensors usually use quantum efficiency as measure of responsivity
Zyla_sCMOS.txtFoveonX3.txt
photons->neural
response units might be photocurrent, or spikes/sec, etc.
HigherPasserinesphotons->action
photosynthesis is an example
BeanPhotosynthesis.txt
material
reflectance
NA
this is the diffuse reflectance
CC_Avg20_spectrum_XYY.txt
transmittanceabsorbance
NA
for color calculations, absorbance is automatically converted to transmittance
HoyaHematoxylin.txtatmosphere2003
responsivity.material
material->electricalmaterial->neuralmaterial->action
NA
a spectrum of this type typically comes from both a light source and a camera
scanner.ACES (a standard for scanning film)Table 2.1. The types of spectra and their quantities
The quantity
is used to label plots,
and to make sense out of the arguments in the function product()
.
The function invert()
implements a method in
Davis G (2019). “A Centroid for Sections of a Cube in a Function Space, with application to Colorimetry.” ArXiv e-prints. 1811.00990, https://arxiv.org/abs/1811.00990.
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