View source: R/colorSpec.radiometric.R
radiometric | R Documentation |
Convert a colorSpec object to have quantity that is radiometric (energy of photons) - to prepare it for colorimetric calculations. Test an object for whether it is radiometric.
## S3 method for class 'colorSpec' radiometric( x, multiplier=1, warn=FALSE ) ## S3 method for class 'colorSpec' is.radiometric( x )
x |
a colorSpec object |
multiplier |
a scalar which is multiplied by the output, and intended for unit conversion |
warn |
if |
If the quantity
of x
does not start with 'photons'
then the quantity is not actinometric
and so x
is returned unchanged.
Otherwise x
is actinometric (photon-based).
If type(x)
is 'light'
then
the most common actinometric unit of photon count is
(μmole of photons) = (6.02214 x 10^{17} photons).
The conversion equation is:
E = Q * 10^{-6} * N_A * h * c / λ
where E is the energy of the photons,
Q is the photon count,
N_A is Avogadro's constant,
h is Planck's constant, c is the speed of light,
and λ is the wavelength in meters.
The output energy unit is joule.
If the unit of Q
is not (μmole of photons),
then the output should be scaled appropriately.
For example, if the unit of photon count is exaphotons,
then set multiplier=1/0.602214
.
If the quantity(x)
is 'photons->electrical'
,
then the most common actinometric unit of responsivity to light is quantum efficiency (QE).
The conversion equation is:
R_e = QE * λ * e / (h * c)
where R_e is the energy-based responsivity,
QE is the quantum efficiency,
and e is the charge of an electron (in C).
The output responsivity unit is coulombs/joule (C/J) or amps/watt (A/W).
If the unit of x
is not quantum efficiency,
then multiplier
should be set appropriately.
If the quantity(x)
is
'photons->neural'
or 'photons->action'
,
the most common actinometric unit of photon count is
(μmole of photons) = (6.02214 x 10^{17} photons).
The conversion equation is:
R_e = R_p * λ * 10^6 / ( N_A * h * c)
where R_e is the energy-based responsivity, R_p is the photon-based responsivity. This essentially the reciprocal of the first conversion equation.
The argument multiplier
is applied to the right side of all the above
conversion equations.
radiometric()
returns a colorSpec object with
quantity
that is
radiometric (energy-based) and not actinometric (photon-based).
If type(x)
is a material type
('material'
or 'responsivity.material'
)
then x
is returned unchanged.
If quantity(x)
starts with 'energy'
,
then is.radiometric()
returns TRUE
, and otherwise FALSE
.
To log the executed conversion equation,
execute cs.options(loglevel='INFO')
.
Wikipedia. Photon counting. https://en.wikipedia.org/wiki/Photon_counting
quantity
,
type
,
F96T12
,
cs.options
,
actinometric
sum( F96T12 ) # the step size is 1nm, from 300 to 900nm # [1] 320.1132 photon irradiance, (micromoles of photons)*m^{-2}*sec^{-1} sum( radiometric(F96T12) ) # [1] 68.91819 irradiance, watts*m^{-2}
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