Mitigation of image artifacts in LWIR microgrid polarimeter images

Bradley M. Ratliff, J. Scott Tyo, James K. Boger, Wiley T. Black, David M. Bowers, Rakesh Kumar

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

7 Scopus citations

Abstract

Microgrid polarimeters, also known as division of focal plane (DoFP) polarimeters, are composed of an integrated array of micropolarizing elements that immediately precedes the FPA. The result of the DoFP device is that neighboring pixels sense different polarization states. The measurements made at each pixel can be combined to estimate the Stokes vector at every reconstruction point in a scene. DoFP devices have the advantage that they are mechanically rugged and inherently optically aligned. However, they suffer from the severe disadvantage that the neighboring pixels that make up the Stokes vector estimates have different instantaneous fields of view (IFOV). This IFOV error leads to spatial differencing that causes false polarization signatures, especially in regions of the image where the scene changes rapidly in space. Furthermore, when the polarimeter is operating in the LWIR, the FPA has inherent response problems such as nonuniformity and dead pixels that make the false polarization problem that much worse. In this paper, we present methods that use spatial information from the scene to mitigate two of the biggest problems that confront DoFP devices. The first is a polarimetric dead pixel replacement (DPR) scheme, and the second is a reconstruction method that chooses the most appropriate polarimetric interpolation scheme for each particular pixel in the image based on the scene properties. We have found that these two methods can greatly improve both the visual appearance of polarization products as well as the accuracy of the polarization estimates, and can be implemented with minimal computational cost.

Original languageEnglish (US)
Title of host publicationPolarization Science and Remote Sensing III
DOIs
StatePublished - Dec 1 2007
EventPolarization Science and Remote Sensing III - San Diego, CA, United States
Duration: Aug 29 2007Aug 30 2007

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume6682
ISSN (Print)0277-786X

Other

OtherPolarization Science and Remote Sensing III
CountryUnited States
CitySan Diego, CA
Period8/29/078/30/07

Keywords

  • Dead pixel replacement
  • Focal plane array
  • Image processing
  • Interpolation
  • Long-wave infrared
  • Microgrid
  • Polarimeter
  • Polarimetry
  • Remote sensing

ASJC Scopus subject areas

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

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  • Cite this

    Ratliff, B. M., Tyo, J. S., Boger, J. K., Black, W. T., Bowers, D. M., & Kumar, R. (2007). Mitigation of image artifacts in LWIR microgrid polarimeter images. In Polarization Science and Remote Sensing III [668209] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 6682). https://doi.org/10.1117/12.737439