Infrared polarization ship images and contrast in the MAPTIP experiment

Cooper, Alfred W.; Lentz, William J.; Walker, P.L.

doi:10.1117/12.254208

Cited by 12 publications

(7 citation statements)

References 2 publications

(2 reference statements)

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“…Conversely, at larger wavenumbers the amount of scattered sunlight during the day is strong enough to increase the reflected-background atmosphere component sufficiently that it dominates the water-emitted radiance, resulting in a net positive (horizontal) polarization state. This kind of polarization signature has been measured (Cooper et al 1996), but the exact amount of positive polarization in the shortwave infrared spectral region depends strongly on atmospheric particulate scattering (Shaw 1999).…”

Section: Infrared Sea Surface Polarizationmentioning

confidence: 99%

“…The impact of partially polarized radiance on radiometric measurements depends primarily on how the polarization alters the overall radiance and how the radiometer response varies with polarization. In fact, this relatively small instrument polarization sensitivity coupled with a similarly small amount of sea surface polarization does not present as big a problem in an application such as sea surface temperature (SST) radiometry as it does in a surveillance application where the polarization signature of a target is being measured (e.g., Egan 2000;Fetrow et al 2000;Howe et al 2000;Zeisse et al 1999;Cooper et al 1996). For these direct polarimetry problems, ignoring the instrument polarization sensitivity would result in an error that easily could be as large as the measured polarization value.…”

Section: Effect Of Polarization Sensitivity On Sea Surface Radiometrymentioning

confidence: 99%

“…In some cases, of primarily military interest, the infrared radiance is measured or calculated polarimetrically to increase contrast between man-made objects and the background (Egan 2000;Fetrow et al 2000;Howe et al 2000;Zeisse et al 1999;Cooper et al 1996). These measurements rely on a difference in polarization state between the target and the background, or quite often even assume that the background is unpolarized.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Instrument Polarization Sensitivity on Sea Surface Remote Sensing with Infrared Spectroradiometers

Shaw¹

2002

J. Atmos. Oceanic Technol.

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The sensitivity of Fourier transform infrared spectroradiometers to the polarization state of incident radiance can become significant in radiometric measurements of a partially polarized source such as the sea surface. At off-nadir incidence angles and wavenumbers below about 2750 cm Ϫ1 (wavelengths longer than 3.6 m), radiance from the sea surface is partially vertically polarized, because the vertically polarized sea surface emission exceeds the horizontally polarized background reflection. At larger wavenumbers (wavelengths shorter than 3.6 m), reflected skylight becomes more significant, and the total radiance at off-nadir angles can become horizontally polarized. This paper shows how the inherent polarization sensitivity (Ϫ5%) of a typical Fourier transform infrared instrument leads to radiometric errors that are small (ϳ0.1 K) but significant for radiometrically demanding sea surface remote sensing applications at large incidence angles. For incidence angles below approximately 45Њ, the polarization-induced error for longwave infrared measurements typically is less than approximately 0.05 K and therefore often can be neglected in sea surface radiometry. However, in polarimetric measurements used, for example, to increase contrast between man-made objects and the background, the instrument polarization sensitivity must be considered always.

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Section: Infrared Sea Surface Polarizationmentioning

confidence: 99%

Section: Effect Of Polarization Sensitivity On Sea Surface Radiometrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Effect of Instrument Polarization Sensitivity on Sea Surface Remote Sensing with Infrared Spectroradiometers

Shaw¹

2002

J. Atmos. Oceanic Technol.

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“…), it has been suggested that by examining the polarization state of the IR image forming radiation, one can significantly improve the ability to see objects that are obscured by background clutter (4,5,6).…”

Section: Introductionmentioning

confidence: 99%

Measured Degree of Infrared Polarization for a Variety of Thermal Emitting Surfaces

Gurton¹,

Dahmani²,

Videen³

2004

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Approved for public release; distribution unlimited. ii REPORT DOCUMENTATION PAGEForm Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)June 2004 ARL-TR-3240 SPONSOR/MONITOR'S ACRONYM(S) 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) U.S. Army Research Laboratory 2800 Powder Mill Road Adelphi, MD 20783-1197 SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution unlimited. SUPPLEMENTARY NOTES ABSTRACTWe report on a series of parametric measurements designed to measure the attenuative effects that surface roughness and aerosol contamination play in reducing polarized thermal surface emission. In particular, we measure the spectrally resolved linear degree of polarization (LDOP) for a series of roughened borosilicate (Pyrex 1 ) glass substrates as a function of roughness parameter, Ra, root mean square slope, m, and the angle of observation, θ. Spectrally resolved LDOP is measured over the waveband region 4 to13 µm by a modified Fourier transform IR spectrometer in which a wire-grid polarizer and an achromatic quarter-wave plate are used in conjunction to measure all four Stokes parameters. A second set of measurements is conducted on similar smooth glass substrates that are subjected to varying degrees of dew formation and aerosol contamination. Test substrates are oriented at a high grazing angle of 80 degrees and placed in a closed chamber. Dew or attenuative particulates, i.e., carbon black, potassium bromide, or pollen particles, are allowed to condense/settle on the thermal emitting surface while a band-averaged LDOP is recorded with a long-wave polarimetric IR imaging system. Measured results are then compared with predictive calculations based on a weighted Fresnel relation.

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“…To improve image contrast between ships and the ocean background, Cooper et al 10,11,13 and Walker et al 12 measured polarized images in the 3-5-and 8 -12-m wavelength bands, finding predominantly p polarization for the sea surface ͑Շ10% at 8 -12 m, less at 3-5 m͒. Sun glitter reduced the amount of p polarization and, especially in the short-wave band, often produced s polarization.…”

Section: Introductionmentioning

confidence: 99%

Degree of linear polarization in spectral radiances from water-viewing infrared radiometers

Shaw

1999

Appl. Opt.

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Infrared radiances from water become partially polarized at oblique viewing angles through both emission and reflection. I describe computer simulations that show how the state of polarization for water varies with environmental conditions over a wavelength range of 3-15 microm with 0.05-microm resolution. Polarization at wavelengths longer than approximately 4 microm generally is negative (p, or vertical) and increases with incidence angle up to approximately 75 degrees, beyond which the horizontally polarized reflected atmospheric radiance begins to dominate the surface emission. The highest p polarization (approximately 4-10%) is found in the atmospheric window regions of approximately 4-5 and 8-14 microm. In the 3-5-microm spectral band, especially between 3 and 4 microm, reflected atmospheric radiance usually is greater than surface emission, resulting in a net s polarization (horizontal). The results of these simulations agree well with broadband measurements of the degree of polarization for a water surface viewed at nadir angles of 0-75 degrees.

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Infrared polarization ship images and contrast in the MAPTIP experiment

Cited by 12 publications

References 2 publications

The Effect of Instrument Polarization Sensitivity on Sea Surface Remote Sensing with Infrared Spectroradiometers

The Effect of Instrument Polarization Sensitivity on Sea Surface Remote Sensing with Infrared Spectroradiometers

Measured Degree of Infrared Polarization for a Variety of Thermal Emitting Surfaces

Degree of linear polarization in spectral radiances from water-viewing infrared radiometers

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