18 August 2005 Combatting infrared focal plane array nonuniformity noise in imaging polarimeters
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Proceedings Volume 5888, Polarization Science and Remote Sensing II; 58880J (2005); doi: 10.1117/12.613075
Event: Optics and Photonics 2005, 2005, San Diego, California, United States
Abstract
One of the most significant challenges in performing infrared (IR) polarimetery is the focal plane array (FPA) nonuniformity (NU) noise that is inherent in virtually all IR photodetector technologies that operate in the midwave IR (MWIR) or long-wave IR (LWIR). NU noise results from pixel-to-pixel variations in the repsonsivity of the photodetectors. This problem is especially severy in the microengineered IR FPA materials like HgCdTe and InSb, as well as in uncooled IR microbolometer sensors. Such problems are largely absent from Si based visible spectrum FPAs. The pixel response is usually a variable nonlinear response function, and even when the response is linearized over some range of temperatures, the gain and offset of the resulting response is usually highly variable. NU noise is normally corrected by applying a linear calibration to the data, but the resulting imagery still retains residual nonuniformity due to the nonlinearity of the photodetector responses. This residual nonuniformity is particularly troublesome for polarimeters because of the addition and subtraction operations that must be performed on the images in order to construct the Stokes parameters or other polarization products. In this paper we explore the impact of NU noise on full stokes and linear-polarization-only IR polarimeters. We compare the performance of division of time, division of amplitude, and division of array polarimeters in the presence of both NU and temporal noise, and assess the ability of calibration-based NU correction schemes to clean up the data.
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Bradley M. Ratliff, Rakesh Kumar, Wiley Black, James K. Boger, J. Scott Tyo, "Combatting infrared focal plane array nonuniformity noise in imaging polarimeters", Proc. SPIE 5888, Polarization Science and Remote Sensing II, 58880J (18 August 2005); doi: 10.1117/12.613075; https://doi.org/10.1117/12.613075
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KEYWORDS
Calibration

Polarimetry

Staring arrays

Signal to noise ratio

Polarization

Infrared imaging

Sensors

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