About

About
This table enables to specify the parameters of the light source to be used in the radiometry calculation(s).

The available light sources are either punctual and isotropic or lambertian with different shapes. As a reminder, isotropic sources have a uniform intensity whatever the direction and lambertian sources have a uniform radiance whatever the direction. More details about isotropic and lambertian sources are provided in the "photometry" tutorial.

The type of source can be selected by clicking on the related radio button. It is either punctual, circular, rectangular, cylindrical or annular. A light source is defined by its power and eventually by its dimension(s). The dimension(s) can be entered in the dedicated cells. The source (if it is punctual) or its center (if it is lambertian) are located at the origin of the object surface.

If the selected source is punctual isotropic or if "no" is selected in the grey body cell, the source power is defined in the related power cell. It is distributed on the different wavelengths activated in the wavelengths table. The power for each individual wavelength is then proportionnal to its weight.

If the source is lambertian, it can be considered as a grey body by selecting "yes" in the grey body cell. In this case, the power used in the calculations is no more the one entered in the power cell related to the concerned source type. it is calculated from its area, its temperature and its emissivity (see the source table tutorial).