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Bidirectional Reflectance (BRDF)

The bidirectional reflectance (BRDF) of a surface is defined as the ratio of the luminous radiance reflected into a unit solid angle to the total incident radiance.

Features and Benefits

BRDF testing can be performed over a wide range of wavelengths by using broad band sources and bandpass filters. Most competitors utilize only laser sources and are restricted to those wavelengths.

The following are features for BRDF measurements made on the standard SOC BRDF goniometer:

  • Wavelengths: 0.4 to 14.0 micron (discrete wavelengths using bandpass filters).
  • Incident Angles: normal incidence to 80° incidence from normal.
  • Reflected Angles: -85 to +85° from normal (in zenith). Full 360° azimuthal (rotational) coverage.
  • Sample size: ½ “ square or diameter up to 10 “ square or diameter.
  • Mapping techniques: In-plane only, In-plane and cross-plane, or Full Hemispherical Mapping (Full Mapping)

SOC has several additional bidirectional reflectometers that are used to obtain bidirectional reflectance data. One such device is unique in that it is designed to measure the direct retroreflection using laser sources. A Michelson interferometer arrangement is used to enable placement of the detector and source on the optical axis opposite the sample. This setup allows the BRDF in the retro direction to be measured using heterodyned detection methods. Wavelengths available for the interferometer are 0.535 and 1.06 microns.



  • Verification of paint and coating
  • Stray light analysis

Energy and Solar Power

  • Determining the specularity (mirror-like qualities) of reflective components.


  • Military defense
  • Aircraft and ground target signature modeling

Remote Sensing

  • Simulator scene generation
  • Ground truth
  • Material mapping