Glossary
- Isotropic light source: light source emitting with a constant intensity whichever the direction
- Intensity ( radiometry ): power emitted by a light source per unit of solid angle ; same term used in photometry
- Aperture : diaphragm limiting the number of light rays that are able to propagate
- Optical system: in geometrical optics, assembly of optical components for redirecting the light in a controlled manner
- Transmission: ratio between transmitted radiation power (or intensity or amplitude) and incident radiation power (or intensity or amplitude)