Papers by Author: C. Quan

Abstract: In this paper, we describe an optical interferometer applied to 3D inspection of microcomponents. The resulting interference fringes that are related to the deformation and surface contour of MEMS-components are analyzed by the fast Fourier transform (FFT) and 3-step phaseshifting algorithms. Experimental results show the feasibility of the proposed method for 3D deformation and surface contour measurement of micro-components.

Abstract: Phase-shifting technique is an effect way to suppress the zero order diffraction and the conjugate term in digital holography. However the phase-shifting error will influence inevitably the evaluation precision in practice operation. In this paper, the deformation evaluation errors by means of two kinds of four-step phase-shifting algorithms, which are in common use in digital holography, are analyzed and compared by computer simulation. In addition, the phase-shifting errors may cumulate or not according to different phase-shifting techniques, and both cases are considered in this paper. The results based on the digital in-line holography show that the two four-step phase-shifting algorithms possess different sensitivity to the phase-shifting errors, and the preferable one, which is more immune to the phase-shifting errors, is educed in conclusion.