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.