An Efficient Polarization Code-Multiplexed 3-D Shape Measurement Method for High-Dynamic Range Objects

The fringe projection profilometry (FPP) method is intensively studied and widely used for its high precision and good antinoise ability. In practical 3-D measurement applications, most metal products do not have the ideal Lambertian surfaces. In addition, too many projected patterns complicate the application of such strategies while improving robustness. We propose a polarization code-multiplexed phase shift (PMPS) method to overcome the above challenges. Our method uses the polarization state of light to assist encoding. The phase is robustly unwrapped with complementary gray-code information in the polarization fringe patterns. Compared with the traditional methods, the PMPS method can efficiently and robustly reconstruct metallic objects under the influence of ambient light with half the number of projected patterns.