luminance signal
1. In television technology, the signal that describes (a) the distribution of brightness levels within the image and (b) the equation for deriving that information from the camera output. [After SMPTE]
2. In composite color television, a signal that has major control of the brightness.
Note: Luminance signal is a linear combination of gamma-corrected primary color signals. [After IEEE 100] [After SMPTE]