Error Model and Two-Phase Correction Method for Indirect Illumination

Phase shifting profilometry (PSP) has the advantages of high accuracy, spatial resolution, and anti-noise ability. However, in addition to random noise, indirect illumination, such as subsurface scattering, inter-reflection, and volume scattering, often occurs in the actual measurement environment, seriously affecting the system accuracy. In this article, a sine series model (SSM) is proposed to simulate the error, which significantly simplifies the computational work. Based on the SSM, a two-phase correction (TPC) method is proposed, where two phases with different frequencies are adopted to suppress the interference caused by indirect illumination and random noise. Moreover, by combining the multiwavelength method to unwrap phase, TPC does not need to project additional patterns. Contrast experiments demonstrate that the proposed TPC method has the performance of reducing the error by 40.8%.