Measurement of 0/45 reflectance factor using nonlinearity corrected array spectroradiometer

The measurement of reflectance factor involves a dynamic range spanning multiple orders of magnitude, and ensuring the linearity of the measurement system is essential for obtaining accurate results. The paper describes an optical configuration capable of reflectance factor measurement and enabling linearity measurement by appropriately modifying it. The linearity calibration facility incorporates a high-temperature blackbody source, an aperture, and a white diffuser together, making the spectral radiance measurement range and relative spectral distribution identical to that of reflectance factor measurements using an integrating sphere light source. This significantly reduces the impact of nonlinearity and spectral stray light, making reflectance factor measurements based on array spectroradiometers more convenient while minimizing measurement uncertainty as much as possible. The 0/45 reflectance factor measurement uncertainty of white diffuse reaches 1.20%-0.54% (k = 2) from 380 nm to 780 nm.