The function computes the product of x with luminsivity.1nm.
This product is an Mx4 matrix, where M is the number of spectra in x.
There are 3 columns for photopic vision, and 1 column for scotopic vision.
These columns are multiplied by the appropriate conversion factors
and the resulting Mx4 matrix is returned.
The 5 power-based input quantities and corresponding photometric outputs are:
| radiant power [\(watt\)] | ---> | luminous flux [\(lumen\)] |
| irradiance [\(watt*m^{-2}\)] | ---> | illuminance [\(lumen*m^{-2} = lux\)] |
| radiant exitance [\(watt*m^{-2}\)] | ---> | luminous exitance [\(lumen*m^{-2} = lux\)] |
| radiant intensity [\(watt*sr^{-1}\)] | ---> | luminous intensity [\(lumen*sr^{-1} = candela\)] |
| radiance [\(watt*sr^-1*m^{-2}\)] | ---> | luminance [\(candela*m^{-2} = nit\)] |
The 2 common energy-based input quantities and corresponding photometric outputs are:
| radiant energy [\(joule\)] | ---> | luminous energy [\(talbot = lumen-second\)] |
| radiant exposure [\(joule*m^{-2}\)] | ---> | luminous exposure [\(talbot*m^{-2} = lux-second\)] |
and there are 3 more obtained by integrating over time.
For example "time-integrated radiance" ---> "time integrated luminance".
But I have not been able to find names for these 3.
The talbot is the unofficial name for a lumen-second.