Evaluation method for noise-induced phase error in fringe projection profilometry.

For noise-induced phase error and phase unwrapping reliability in fringe projection profilometry (FPP), a new evaluation method is proposed. By introducing a Gaussian noise model, the maximum variance of the noise-induced phase error and phase unwrapping reliability are directly obtained. According to the proposed evaluation method, the variance of the noise-induced phase error is proportional to the noise variance and inversely proportional to the fringe modulation. The phase unwrapping reliability is not only inversely proportional to the noise-induced phase error, but also inversely proportional to the fringe frequency ratio. This work analyzes and compares three efficient dual-frequency phase unwrapping algorithms. The results show that the wrapped phase accuracy and phase unwrapping reliability based on 4+4 are the best, followed by 3+3 and 3+2. However, 3+2 has the highest measurement efficiency.