Object detection with a field-portable spectropolarimetric imager

Abstract

A relatively compact, lightweight, and programmable spectropolarimetric imager was used to collect spectral and polarization data from various objects and backgrounds, both in the laboratory and in field tests. This imager uses a tellurium dioxide (TeO2) acousto-optic tunable filter and a liquid-crystal retardation plate with a CCD camera. The spectral images were collected 450-1000 nm at 10- or 20-nm intervals at two or four polarization settings for each spectral interval. We analyzed a portion of these data to assess the effectiveness of this system for object detection. We present our measurements and discuss the analysis results.

Performance characterization of VNIR and SWIR spectropolarimetric imagers

“…We developed a compact hyperspectral/polarization imager that provides each spectral image with two linear incident polarizations using an acousto-optic tunable filter (AOTF) in combination with a voltage-controlled liquid crystal variable retarder (LCVR) and investigated development of different types of spectropolarimetric imagers with AOTFs. [1][2][3][4] We also developed a full Stokes polarization imager using an AOTF with two LCVRs. 5 Recently, we developed two separate spectropolarimetric imagers, one operating in the visible-near-infrared (VNIR) spectral region from 450 to 800 nm and the second in the shortwave-infrared (SWIR) region from 1000 to 1600 nm.…”

Compact and static Fourier transform imaging spectropolarimeters using birefringent elements

“…Imaging spectropolarimetry are a valuable technology for performing smart detection and recognition of objects and backgrounds. This technology have already generated intense interest in some fields such as remote sensing [3,4], machine vision [5], and biomedical diagnosis [6], etc. Imaging spectropolarimeter operating in the passive mode is usually employed for ground, airborne and spaceborne remote sensing [7,8].…”

“…LCTF, AOTF, LCVR, rotating retarders or polarizers, etc.) with imaging spectrometers, jitter noise and beam wander from the elements must be considered and minimized [4,5,9,10]. Novel imaging spectropolarimeters based on channeled spectropolarimetry or polarizmetric spectral intensity modulation arouse wide interests due to their snapshot polarimetric imaging capability [11][12][13][14][15][16][17].…”

“…of the interference terms in Eqs (5). can reconstruct input spectral intensity ( , , ) the equal high spectral resolution.…”

Growth of Hg2Cl2 and Hg2Br2 single crystals by physical vapor transport

“…for detection of targets, backgrounds, and stand-off chemical and biological agents [6][7][8], for more than 30 years [9] AO devices are solid-state RF tunable devices that contain no moving parts and are compact, rugged, and highly efficient. High efficiency translates directly into lower operating power, higher sensitivity, and faster data acquisition.…”