luminance
/ˈljuːmɪnəns/noun
mass noun
1- Physics the intensity of light emitted from a surface per unit area in a given direction【物理】亮度。
1.1
- the component of a television signal which carries information on the brightness of the image（电视信号中的）亮度信号。
词源
late 19th cent. （as a general term meaning 'light, brightness'）： from Latin luminant- 'illuminating'（from the verb luminare） + -ANCE.