Luminance while imaging luminance meters measure luminance in a way similar to the way a digital camera records color images. Luminance Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted or reflected from a particular area, and falls within a given solid angle. The SI unit for luminance is candela per square metre (cd/m). A non-SI term for the same unit is the nit. The CGS unit of luminance is the stilb, which is equal to one candela per square
Measure (mathematics) if is a finite real number (rather than ∞). Nonzero finite measures are analogous to probability measures in the sense that any finite measure is proportional to the probability measure formula_15. A measure is called "σ-finite" if can be decomposed into a countable union of measurable sets of finite measure. Analogously, a set in a measure space is said to have a "σ-finite measure" if it is a countable union of sets with finite measure. For example, the real numbers with the standard Lebesgue measure are σ-finite but not finite. Consider the closed intervals for all integers ; there are