Phase-error restraint with the empirical mode decomposition method in phase measurement profilometry

Phase measurement profilometry (PMP) uses a digital projector and a camera for 3D shape measurement. However, the nonlinear response of the measurement system causes the captured perfect sinusoidal fringe patterns to become non-sinusoidal waveforms, which results in phase and measurement errors. We perform a theoretical analysis of the phase error resulting from non-sinusoidal fringe patterns. Based on a derived phase-error expression, the empirical mode decomposition (EMD) method is introduced to restrain nonlinear phase error and improve the precision in evaluating the phase distribution. A computer simulation and experimental results prove that the proposed method can eliminate possible phase-error in PMP.