Birefringence compensation for single-shot 3D profilometry using a full-Stokes imaging polarimeter

We demonstrate a single-shot uniaxial 3D profilometry system that illuminates a sample with a structured polarization pattern and measures the reflected full-Stokes polarimetric image. Some non-contact 3D measurements require evaluating samples located in a protected environment. For example, this may be a sample under the lid of an acrylic Petri dish, a sample that has a protective film overlay, or products housed inside a plastic container. To deal with these cases, we adapt our measurement system to capture the complete polarization state using a single-shot full-Stokes imaging system consisting of two polarization cameras. This system cannot only measure the dynamic 3D shape at video rate, but can also compensate for any birefringent layers between the illumination arm and the sample under measurement. We present the measurement principles of the system and show the results of a real-time 3D profilometry experiment in which a sample was measured under the lid of an acrylic Petri dish.