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Title
Mueller Characterization for Partial Polarimetry
Abstract
Polarization carries information about the geometry, texture, and material of a light-matter interaction beyond what is available through purely radiometric measurements. This information is contained in the Mueller matrix (MM) for a linear light-matter interaction. Characterizing the complete MM requires a minimum of 16 linearly independent polarization measurements, though more measurements are commonly performed for improved robustness to measurement noise. However, performing 16 or more polarization measurements can be prohibitively complex or expensive for many applications. This dissertation work explores the utilization of a priori knowledge of the subset of MMs that will be measured in a given application for the purpose of designing effective partial polarimeters. This a priori information can come in the form of an initial MM characterization of the exact scene to be measured again later or as a more general representation of the polarized scattering response of a material.
Chapter 2 of this dissertation overviews the mathematics and physics utilized in the subsequent chapters. Chapter 3 describes the optimization of polarization generator and analyzer states for maximizing the contrast in a single snapshot of in vivo human eyes. Eyes are both spatially-varying and subject to unconscious random movements, meaning that both spatial- and time-modulation techniques for capturing the MM have significant tradeoffs. Chapter 4 describes a method for efficiently performing and tabulating MM data as a function of scattering geometry. This tabulated data can be used as a lookup table that is interpolated or as the basis for creating analytic models. Chapter 5 introduces an original polarized scattering model which mixes first-surface and diffuse polarized reflection as a function of scattering geometry. Chapter 6 uses the models from the previous Chapter to describe the polarized scattering response of two materials. These models as well as knowledge of the scattering geometries captured within an image are used to estimate a depolarization parameter and to extrapolate the MM image from only four polarization measurements.