Spectro-Polarimetric Imaging for Object Recognition

We have built an all-electronic spectro-polarimetric imaging camera utilizing an acousto-optic tunable filter and a liquid crystal variable retardation plate. This combination of rapidly adjustable parameters allows operation at 30/sec. frame rate, and near real time adaptability to changing target signatures. The spectral capability of the AOTF permits us to apply simultaneous, multiple wavelength filtering which greatly increases selectivity. Electronically agile polarization analysis adds a valuable signature feature for many scenarios. The adjustable retardation gives the capability to analyze and display not only linear polarization, but more generally, elliptical polarization as well. We have developed background suppression algorithms based on spectral and polarization signatures so that a wide variety of targets may be displayed with greatly enhanced contrast.