luxmetri

Luxmetri is a measurement instrument used to quantify illuminance, the amount of light incident on a surface per unit area, expressed in lux. The term is used in several languages to denote devices that measure light levels and is often synonymous with luxmeter. A luxmetri typically comprises a light-sensitive sensor, a light-path window or optics, some form of spectral weighting to reflect human perception, signal processing electronics, and a display or data port. Handheld models enable field measurements, while fixed or integrated devices are used in lighting-control systems and environment monitoring.

Principle: The sensing element converts incoming radiant flux into an electrical signal. For photometric readings, the sensor output is weighted to resemble the photopic luminous efficiency function, so the result corresponds to perceived brightness in lux. Many units implement cosine correction to maintain accuracy for oblique radiation, and include temperature and spectral content compensation. Calibration is performed against traceable lux standards, and manufacturers provide correction factors for different spectral power distributions and measurement geometries.

Applications and standards: Luxmetri are used in architectural lighting design to verify compliance with illumination targets, in occupational safety to ensure adequate working light, in product testing, displays, and horticultural research where light levels affect growth. In professional use, measurements are reported with stated uncertainty and traceability to national or international standards bodies.