Photometry (optics)

Measurement of visible light

Photometry is a branch of optics that deals with measuring light in terms of its perceived brightness to the human eye. It is concerned with quantifying the amount of light that is emitted, reflected, transmitted, or received by an object or a system. Photometric quantities (e.g., luminous flux) are related to their radiometric analogs (e.g., radiant flux) through standardized luminous efficiency functions that model the spectral sensitivity of the human visual system.

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