colorSpec (version 0.5-3)

radiometric: force a colorSpec object to be radiometric

Description

convert a colorSpec object to have quantity that is radiometric (power of photons) - to make it ready for colorimetric calculations

Usage

## S3 method for class 'colorSpec':
radiometric( x )

Arguments

x
a colorSpec object

Value

  • radiometric returns a colorSpec object with quantity that is radiometric (power of photons) and not actinometric (number of photons).

source

Wikipedia. Photon counting. http://en.wikipedia.org/wiki/Photon_counting

Details

If the quantity starts with 'power' then x is returned unchanged. And if the type of x is 'material' or 'responsivity.material' then x is returned unchanged. Otherwise, the quantity starts with 'photons' so the quantity of x is actinometric (proportional to number of photons/sec). If the type is 'light' then the most common actinometric unit of photon flux is ($\mu$mole of photons)/sec. The conversion equation is: $$p = x * (10^{-6} * N_A * h * c / \lambda)$$ where $p$ is proportional to the power of photons, $x$ is the photon flux, $N_A$ is Avogadro's constant, $h$ is Planck's constant, $c$ is the speed of light, and $\lambda$ is the wavelength in meters. The output power unit is watts. If the unit of x is not ($\mu$mole of photons)/sec, then the output should be scaled appropriately. For example, if the photon flux is exaphotons/sec, then divide the output by 0.6022. If the type is 'responsivity.light', then the most common actinometric unit of responsivity to light is quantum efficiency (QE). The conversion equation is: $$r = x * \lambda * e / (h * c)$$ where $r$ is the responsivity, $x$ is the quantum efficiency, and $e$ is the charge of an electron (in C). The output responsivity unit is amps/watt (A/W) or coulombs/joule (C/J). If the unit of x is not quantum efficiency, then the output should be scaled appropriately.

See Also

quantity, type, F96T12

Examples

Run this code
sum( F96T12 ) 
# [1] 320.1132  photon irradiance, (micromoles of photons)*m^{-2}

sum( radiometric(F96T12) )
# [1] 68.91819  irradiance, watts*m^{-2}

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