Calibration and Compensation of Instrumental Errors in Imaging Polarimeters

摘要

The measurement and exploitation of polarization information has become a high priority in a variety of Air Force and DoD remote sensing missions. Polarization provides a useful dimension of information that helps to characterize shape and surface characteristics of interesting targets in optical imagery from the UV through the LWIR and beyond. There are a number of ongoing efforts that are developing specific instruments to quantitatively measure polarization information across a scene. We have discovered that polarization is important, but it can also be quite difficult to measure accurately. Optical systems designed to respond to polarization information are usually more complex than those that respond to spectral information. In addition, most polarimeters require linear combinations of multiple looks at a single pixel in order to infer the polarization parameters. In contrast, most spectral imagers (certain Fourier transform devices excepted) can form the spectrum at a pixel in a single integration time without comparing measurements from different sensors. Because polarization imagers are more complex, uncalibrated instrumental errors can be even more damaging to the quality of the final imagery. This research project was focused on understanding the instrumental effects on imaging polarimeters and compensating for them in the final imagery.