Difference between Luma and Luminance

There are actually three related terms:

  • Luminance is a physical measure which represents the luminous intensity per unit area of light travelling in some direction. The units are candela per square metre. This is, if you like, an objective measure of how "intense" light is.
  • Relative luminance is a measure how "intense" light appears to a human; since humans can't see X-rays or infra-red, that doesn't register. The CIE [国际照明学会] standard defines a "standard observer"  under various conditions. This is normalised into a range from 0 to 1 or 0 to 100, where the higher value is a reference white.
  • Luma is defined as the relative luminance calculation performed on a gamma-compressed video signal.
posted on 2022-08-08 11:41  华容道专家  阅读(141)  评论(0)    收藏  举报