Uncertainty-Aware Polarimetric Inverse Rendering for Layered Dielectrics with Credible Intervals, Identifiability, and Coverage Calibration

Edwin R. Hancock1,
1University of York, Deramore Lane, York YO10 5GH, UK
DOI: https://doi.org/10.71448/bcds2121-3
Published: 30/12/2021
Cite this article as: Edwin R. Hancock, . Uncertainty-Aware Polarimetric Inverse Rendering for Layered Dielectrics with Credible Intervals, Identifiability, and Coverage Calibration. Bulletin of Computer and Data Sciences, Volume 2 Issue 1. Page: 17-27.

Abstract

Polarization-based capture recovers material parameters of layered dielectrics, but most pipelines report only point estimates. We introduce a Bayesian inverse-rendering framework that yields posteriors and pixelwise credible intervals for surface roughness r, surface–subsurface balance β, absorption a, and refractive index n. A bounded-support likelihood for DOP, heavytailed residuals for intensity, hierarchical priors, and optional spectral coupling ensure stability across geometries and wavelengths. We derive identifiability diagnostics (Fisher information, profile likelihoods) and validate uncertainty via simulation-based calibration and empirical coverage. On synthetic data and real captures (leaves, fruit, plastics/coatings), our method preserves accuracy, meaningfully uses grazing angles, and exposes regimes where parameters are weakly identifiable—insights invisible to point estimates.

Keywords: Polarimetric imaging, degree of polarization (DOP), layered dielectrics, inverse rendering, Bayesian uncertainty quantification, hierarchical priors, Laplace approximation

Abstract

Polarization-based capture recovers material parameters of layered dielectrics, but most pipelines report only point estimates. We introduce a Bayesian inverse-rendering framework that yields posteriors and pixelwise credible intervals for surface roughness r, surface–subsurface balance β, absorption a, and refractive index n. A bounded-support likelihood for DOP, heavytailed residuals for intensity, hierarchical priors, and optional spectral coupling ensure stability across geometries and wavelengths. We derive identifiability diagnostics (Fisher information, profile likelihoods) and validate uncertainty via simulation-based calibration and empirical coverage. On synthetic data and real captures (leaves, fruit, plastics/coatings), our method preserves accuracy, meaningfully uses grazing angles, and exposes regimes where parameters are weakly identifiable—insights invisible to point estimates.

Keywords: Polarimetric imaging, degree of polarization (DOP), layered dielectrics, inverse rendering, Bayesian uncertainty quantification, hierarchical priors, Laplace approximation
Edwin R. Hancock
University of York, Deramore Lane, York YO10 5GH, UK

DOI

Cite this article as:

Edwin R. Hancock, . Uncertainty-Aware Polarimetric Inverse Rendering for Layered Dielectrics with Credible Intervals, Identifiability, and Coverage Calibration. Bulletin of Computer and Data Sciences, Volume 2 Issue 1. Page: 17-27.

Publication history

Copyright © 2021 Edwin R. Hancock, . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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