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Summary
DescriptionEtendue.svg
English: In Optics, the concept of “etendue” is necessary to study luminance and other related quantities.
Σ: a light source with a non-zero area
S: an illuminated surface
dΣ, dS: corresponding differential surface elements
nΣ, nS: unit vectors normal to dΣ, dS
θΣ, θS: angles between nΣ, nS and the line joining dΣ, dS
ΩΣ, ΩS: solid angles subtended at dΣ, dS respectively by dS, dΣ
Español: En óptica, el concepto of “extensión” es necesario para estudiar la luminancia y otras magnitudes relacionadas.
Σ: una fuente de luz con área mayor a cero
S: una superficie iluminada
dΣ, dS: elementos diferenciales de superficie respectivos
nΣ, nS: vectores unitarios normales a dΣ, dS
θΣ, θS: ángulos entre nΣ, nS y la línea recta que une dΣ, dS
ΩΣ, ΩS: ángulos sólidos subtendidos en dΣ, dS respectivamente por dS, dΣ
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