Terminology

The appellation acuteness refers carefully to the bulk of ablaze that is emitted per assemblage of time and per assemblage of surface, in units of lux. Note, however, that in abounding fields of science this abundance is alleged beaming emittance, as against to beaming intensity, which is a altered quantity. These distinctions, however, are abundantly extraneous to gamma compression, which is applicative to any array of normalized beeline intensity-like scale.

Luminance can beggarly several things even aural the ambience of video and imaging:

Luminance is the photometric accuracy of an object, demography into annual the wavelength-dependent acuteness of the animal eye (in units of cd/m²);

Luminance (video) is the encoded video "luma" signal, i.e. agnate to the arresting voltage VS.

Luminance (relative) is the luminance arresting acclimated in a color-space encoding, about to a white level.

One contrasts "luminance" in the faculty of blush (no gamma compression) with "luma" in the faculty of video (with gamma compression), and denote luminance by Y and luma by Y′, the prime aspect (′) cogent gamma compression.8

Likewise, accuracy is sometimes activated to assorted measures, including ablaze levels, admitting it added appropriately applies to a abstract beheld attribute.

Gamma alteration is a blazon of ability law action whose backer is the Greek letter gamma (γ). It should not be abashed with the algebraic Gamma function. The lower case gamma, γ, is a constant of the former; the high case letter, Γ, is the name of (and aspect acclimated for) the closing (as in Γ(x)). To use the chat "function" in affiliation with gamma correction, one may abstain abashing by adage "generalized ability law function."

Without context, a amount labeled gamma ability be either the encoding or the adaptation value. Caution have to be taken to accurately interpreting the amount as that to be applied-to-compensate or to be compensated-by-applying its inverse. In accepted parlance, in abounding occasions the adaptation amount (as 2.2) is active as if it were the encoding value, instead of its changed (1/2.2 in this case) which is the absolute amount that have to be activated to encode gamma.