andibarg / photometry-converter

Converts between photometric units (lumen, candela) and radiometric units (milliwatt).

photometry-converter

Converts between photometric and radiometric units. Supports luminous intensity (in candela), lumious flux (in lumen) and radiant flux/optical power (in milliwatt). Takes into account the spectral emission and beam profile of a light source. See labsphere technical guide for details about the theory.

Installation

$ git clone https://github.com/andibarg/photometry-converter.git
$ cd photometry-converter

Usage

The following example code converts from milliwatt to lumen to candela. The spectrum is a gaussian peak around 457 nm with a bandwith of 27 nm. The beam profile is according to Lambert's cosing law.

import photometry_converter as pc

mW = 827
specdata = pc.gauss_emission(cwvl=457,sbw=27)
beamdata = pc.lambert()

lm = pc.mW2lm(mW, specdata)
cd = pc.lm2cd(lm, beamdata)

Alternatively, you can create a class instance. In the following example the beam profile is specified via the apexangle:

import photometry_converter as pc

led = pc.source(name = 'Blue LED',
                mW = 827,
                specdata = pc.gauss_emission(cwvl=457,sbw=27),
                apexangle = 120)
led.mW2lm()
led.lm2cd()

led.lm
led.cd

The example conversion above may be complemented by the following figures, which show the emission spectrum and the beam profile of the light source: