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The Extension of the NIST BRDF Scale from 1100 nm to 2500 nm



Howard W. Yoon, David W. Allen, George P. Eppeldauer, Benjamin K. Tsai


Measurements of bi-directional reflectance factor for diffuse reflectance from 1100 nm to 2500 nm using extended-range indium gallium arsenide (exInGaAs) detectors in the NIST Spectral Tri-function Automated Reference Reflectometer (STARR) facility are described. The determination of bi-directional reflectance factor with low uncertainties requires the exInGaAs radiometer to be characterized for low-noise performance, linearity and spatial uniformity. The instrument characterizations will be used to establish a total uncertainty budget for the reflectance factor. To independently check the bi-directional reflectance factors, measurements also were made in a separate facility in which the reflectance factor is determined using calibrated spectral irradiance and radiance standards. The total combined uncertainties for the diffuse reflectances range from < 1 % at 1100 nm to 2.5 % at 2500 nm. At NIST, these measurement capabilities will evolve into a calibration service for diffuse spectral reflectance in this wavelength region.
Proceedings Title
Conference Dates
August 3-7, 2009
Conference Location
San Diego, CA


Absolute Reflectance, Bi-Directional Reflectance Factors, Infrared, Pressed PTFE


Yoon, H. , Allen, D. , Eppeldauer, G. and Tsai, B. (2009), The Extension of the NIST BRDF Scale from 1100 nm to 2500 nm, SPIE, San Diego, CA, [online], (Accessed July 15, 2024)


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Created August 21, 2009, Updated February 19, 2017