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
Isotropic measure Isotropic measure In probability theory, an isotropic measure is any mathematical measure that is invariant under linear isometries. It is a standard simplification and assumption used in probability theory. Generally, it is used in the context of measure theory on formula_1-dimensional Euclidean space, for which it can be intuitive to study measures that are unchanged by rotations and translations. An obvious example of such a measure is the standard way of assigning a measure to subsets of "n"-dimensional Euclidean space: Lebesgue measure. An isotropic measure on formula_2 is a (Borel) measure that is absolutely continuous on formula_3 and that is