Brightness is a subjective term for the strength or intensity of a visual perception of visible light.
The illuminance Ev (“v” for visual) is the photometric equivalent of the irradiance Ee in radiometry. Photometric quantities and units describe visible light according to the physiological perception of brightness by the human eye. Accordingly, the illuminance is equal to the irradiance in the spectral range of the human eye. Colloquially, it describes the “intensity” […]
The irradiance Ee (“e” for energetic) or radiant flux density is the total power of electromagnetic energy passing through a surface and is a radiometric quantity. It correctly describes the “intensity” of lighting in image processing. The SI unit is W/m² (=power per area) In order to quantify the “intensity” for lighting in the visible […]
