Shape reconstruction of heritage assets by polarization information

Three-dimensional modeling of heritage assets poses a challenge when high reflectance and featureless surfaces are involved. Because of the complex reflection characteristics, traditional methods, either passive or active, tend to generate noisy and incomplete reconstruction results. To address this, we introduce in this paper a shape-from-polarization system and modeling strategy for the 3-D reconstruction of heritage assets. As demonstrated, by analyzing polarization properties of reflected light, we can generate by a single image pixel-level-resolution normal and depth maps. We consider two system prototypes involving a point light source but different in the polarizing camera configurations. They provide solutions for different reconstruction requirements and acquisition conditions. Our reconstruction model is common however to both involving a closed set of simple computation steps. Our evaluations demonstrate how the proposed method significantly improves the 3-D surface model completeness and level of detail, showing its suitability and value to reach the goal of a high-resolution survey of heritage assets, where traditional approaches tend to fail.