Proceedings Article | 4 May 2010
Proc. SPIE. 7664, Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XV
KEYWORDS: Polarimetry, Sensors, Long wavelength infrared, Staring arrays, Target detection, Thermography, Calibration, Polarizers, Infrared imaging, Objectives
We present a comparative study involving five distinctly different polarimetric imaging platforms that are designed
to record calibrated Stokes images (and associated polarimetric products) in either the MidIR or LWIR spectral
regions. The data set used in this study was recorded during April 14-18, 2008, at the Russell Tower Measurement
Facility, Redstone Arsenal, Huntsville, AL. Four of the five camera systems were designed to operate in the LWIR
(approx. 8-12μm), and used either cooled mercury cadmium telluride (MCT) focal-plane-arrays (FPA), or a near-room
temperature microbolometer. The lone MidIR polarimetric sensor was based on a liquid nitrogen (LN2) cooled
indium antimonide (InSb) FPA, resulting in an approximate wavelength response of 3-5μm. The selection of
cameras was comprised of the following optical designs: a LWIR "super-pixel," or division-of-focal plane (DoFP)
sensor; two LWIR spinning-achromatic-retarder (SAR) based sensors; one LWIR division-of-amplitude (DoAM)
sensor; and one MidIR division-of-aperture (DoA) sensor. Cross-sensor comparisons were conducted by examining
calibrated Stokes images (e.g., S0, S1, S2, and degree-of-linear polarization (DOLP)) recorded by each sensor for a
given target at approximately the same test periods to ensure that data sets were recorded under similar atmospheric
conditions. Target detections are applied to the image set for each polarimetric sensor for further comparison, i.e.,
conventional receiver operating characteristic (ROC) curve analysis and an effective contrast ratio are considered.
