Perspective Phase Angle Model for Polarimetric 3D Reconstruction

TL;DR

This paper introduces the perspective phase angle (PPA) model for polarimetric 3D reconstruction, improving accuracy over traditional orthographic models by accounting for perspective projection effects.

Contribution

The paper proposes the PPA model that accurately relates polarization phase angle to surface normals under perspective projection, enabling single-view normal estimation without $ ext{pi}$-ambiguity.

Findings

PPA model outperforms orthographic models in accuracy

Single-view phase angle maps suffice for normal estimation

Model effectively handles large field of view scenarios

Abstract

Current polarimetric 3D reconstruction methods, including those in the well-established shape from polarization literature, are all developed under the orthographic projection assumption. In the case of a large field of view, however, this assumption does not hold and may result in significant reconstruction errors in methods that make this assumption. To address this problem, we present the perspective phase angle (PPA) model that is applicable to perspective cameras. Compared with the orthographic model, the proposed PPA model accurately describes the relationship between polarization phase angle and surface normal under perspective projection. In addition, the PPA model makes it possible to estimate surface normals from only one single-view phase angle map and does not suffer from the so-called $\pi$-ambiguity problem. Experiments on real data show that the PPA model is more accurate for surface normal estimation with a perspective camera than the orthographic model.