Photometric measurements bias the radiant power at each wavelength with a luminosity function, which models human spectral sensitivity, to account for this variation. The photopic sensitivity function ...

Various optical systems or geometries can be used to perform light measurements. For instance, the total power [flux] of a light source can be measured in all directions, in a specific direction or ...

A nanocandela (ncd) is a unit of luminous intensity in the International System of Units (SI), equivalent to one billionth of a candela (cd). The candela measures the light emitted by a source in a ...