Triple N-Step Phase Shift Algorithm for Phase Error Compensation in Fringe Projection Profilometry

For fringe projection profilometry (FPP), the nonlinear response of the camera and projector in a 3D measurement system causes the captured fringe to be non-sinusoidal, which results in periodic phase errors. This paper reports a theoretical analysis of the phase error caused by the non-sinusoidal fringe, and proposes a triple N-step phase shift (PS) algorithm. Experimental results demonstrate that the proposed algorithm outperforms the existing double N-step phase shift algorithm in terms of reducing the phase error caused by the non-sinusoidal captured fringe.