Model-independent nonlinearity rectification algorithm using a phase-probability-equalization-based look-up table

In the fringe projection system, nonlinearities often result in severe artifacts, such as the gamma effect and the phase-shifting error. Most previous methods can only eliminate the nonlinearity of a particular model. Additionally, the problems of coupling nonlinearities are difficult to solve. Therefore, this paper proposes a model-independent nonlinear rectification algorithm. By applying phase probability equalization (PPE) on several complete periods of a flat area, we built a look-up table (LUT) between the phase error and the wrapped phase, and retrieved an accurate phase with the subtraction of a searched phase error. The simulation and experimental results show that, compared with the traditional full-field PPE algorithm, the proposed algorithm is more robust to the object height distributions and has better rectification on incomplete fringe periods. Besides, the proposed algorithm also has higher efficiency because of the characteristics of local processing and noniterative characteristics.