Division of focal plane (DoFP), or integrated microgrid polarimeters, typically consist of a 2 × 2 mosaic of linear polarization filters overlaid upon a focal plane array sensor and obtain temporally synchronized polarized intensity measurements across a scene, similar in concept to a Bayer color filter array camera. However, the resulting estimated polarimetric images suffer a loss in resolution and can be plagued by aliasing due to the spatially-modulated microgrid measurement strategy. Demosaicing strategies have been proposed that attempt to minimize these effects, but result in some level of residual artifacts. In this work we propose a conditional generative adversarial network (cGAN) approach to the microgrid demosaicing problem. We evaluate the performance of our approach against full-resolution division-of-time polarimeter data as well as compare against both traditional and recent microgrid demosaicing methods. We apply these demosaicing strategies to data from both real and simulated visible microgrid imagery and provide an objective criteria for evaluating their performance. We demonstrate that the proposed cGAN approach results in estimated Stokes imagery that is comparable to full-resolution ground truth imagery from both a quantitative and qualitative perspective.
Linear division of focal plane (DoFP), or integrated microgrid polarimeters, provide a measurement strategy for obtaining time-synchronized polarized intensity measurements across a scene. This is accomplished by masking pixels in the focal plane array sensor with a repeating pattern of different linear polarizers. The convention in industry has been to use a repeating
2
×
2
pattern of four linear polarizers with chosen polarizer orientation angles of
{
0
,
45
,
90
,
135
}
∘
. Alternative designs based upon other
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Q
modulation patterns have been proposed that demonstrate improved performance over conventional microgrid arrays due to better utilization of bandwidth in the frequency domain. Here, we develop a model for linear DoFP snapshot polarimeters that provides an in-depth understanding of these devices in both the spatial and frequency domains and relate this model to previously reported generalized DoFP channeled polarimeter models. We then use the model to identify practical modulation patterns and study their performance through empirical simulations based upon data collected from real polarimeters. We demonstrate the validity of the developed model and compare the performance of the identified modulation schemes against a common set of ground truth images. We find that choosing alternative sets of polarizer angles, in conjunction with modulators that improve bandwidth usage, result in the best overall designs that can improve performance over conventional microgrid polarimeters.
I would like to acknowledge the Jamestown Area Foundation for financially supporting me through my bachelor's degrees and masters' degree. The Bruce Higham scholarship awarded to me by the Jamestown Area Foundation was vital to my success here at the University of Dayton. I
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