Hemispherical scatter instrument for reflectance function measurement based on the discrete-ordinates method

Mauricio A. Sanchez; William H. Sutton; Carlos P. Borras

doi:10.1117/12.543475

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5 August 2004 Hemispherical scatter instrument for reflectance function measurement based on the discrete-ordinates method

Mauricio A. Sanchez, William H. Sutton, Carlos P. Borras

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Proceedings Volume 5431, Targets and Backgrounds X: Characterization and Representation; (2004) https://doi.org/10.1117/12.543475
Event: Defense and Security, 2004, Orlando, Florida, United States

Abstract

We present a new portable infrared-based hemispherical scatterometer to rapidly and accurately determine out of plane reflectance function (BRDF) of homogeneous surfaces. The position of the 12 detectors has been selected based on angular distribution scheme of the S4 quadrature of the discrete-ordinates method. The reflectance data obtained from this device can be directly applied to radiation transport schemes for problems involving highly accurate surface characterization. With this instrument infrared energy scattering can be performed in multiple directions and sequences at the same time. With measurements for a variety of fire barrier materials used in non-bearing walls we demonstrated the usefulness of this apparatus over a limited range of scattering directions. Verification of the measurements is done by comparing theoretical and experimental data of radiative intensity distribution in fire blanket insulation when impinged by a collimated flux and using an opaque reflector with arbitrary properties but previously determined reflectance function as a radiative boundary. The same equipment can be used to measure other radiative properties for different materials and it has been envisioned as a portable tool for rapid property and surface defects estimation in manufacturing processes.

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Mauricio A. Sanchez, William H. Sutton, and Carlos P. Borras "Hemispherical scatter instrument for reflectance function measurement based on the discrete-ordinates method", Proc. SPIE 5431, Targets and Backgrounds X: Characterization and Representation, (5 August 2004); https://doi.org/10.1117/12.543475

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