Spectral invariance hypothesis study of polarized reflectance with Ground-based Multiangle SpectroPolarimetric Imager (GroundMSPI)

Christine L. Bradley, Meridith Kathryn Kupinski, David J. Diner, Feng Xu, Russell A Chipman

Research output: Chapter in Book/Report/Conference proceedingConference contribution

11 Scopus citations


Many models used to represent the boundary condition for the separation of atmospheric scattering from the surface reflectance in polarized remote sensing measurements assume that the polarized surface reflectance is spectrally neutral. The Spectral Invariance Hypothesis asserts that the magnitude and shape of the polarized bidirectional reflectance factor (pBRF) is equal for all wavelengths. In order to test this hypothesis, JPL's Ground-based Multiangle SpectroPolarimetric Imager (GroundMSPI) is used to measure polarization information of different outdoor surface types. GroundMSPI measures the linear polarization Stokes parameters (I, Q, U), at three wavelengths, 470 nm, 660 nm, and 865 nm. The camera is mounted on a two-Axis gimbal to accurately select the view azimuth and elevation directions. On clear sky days we acquired day-long scans of scenes that contain various surface types such as grass, dirt, cement, brick, and asphalt and placed a Spectralon panel in the camera field of view to provide a reflectance reference. Over the course of each day, changing solar position in the sky provides a large range of scattering angles for this study. The polarized bidirectional reflectance factor (pBRF) is measured for the three wavelengths and the best fit slope of the spectral correlation is reported. This work reports the range of best fit slopes measured for five region types.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
ISBN (Print)9781628417791
StatePublished - 2015
EventPolarization Science and Remote Sensing VII - San Diego, United States
Duration: Aug 11 2015Aug 12 2015


OtherPolarization Science and Remote Sensing VII
CountryUnited States
CitySan Diego


  • land surface reectance
  • Multiangle Spec-TroPolarimetric Imager (MSPI)
  • pBRDF
  • pBRF
  • spectral invariance
  • spectrally neutral

ASJC Scopus subject areas

  • Applied Mathematics
  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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