Polarization-Based Surface Normal Estimation of Black Specular Objects from Multiple Viewpoints

Polarization is physical phenomena of the light which gives rich information of the scene even though it is undetectable by human eyes. In this paper, we analyze the polarization state of the light reflected on black specular objects in order to estimate the surface normal of the objects. Since polarization image of single view is not enough to uniquely determine the surface normal, we observe the object from multiple views. A rough estimate of the object geometry is obtained a priori by space carving so that the polarization state of the reflected light can be analyzed at the same surface point under multiple views. Unlike the photometric stereo or the multiview stereo which cannot estimate the surface normal and the geometry of black specular objects, the proposed method which is based on the polarization analysis and the space carving can estimate the surface normal and the geometry of black specular objects.