A high level of immunity to vibration required for on-machine measurements is demonstrated by the continuous phaseshifting interferometer described in this work. Phase measurement errors caused by environmental disturbance and mechanical instability are eliminated by Fourier analysis on a few hundreds of fringes captured by a high-speed CMOS camera. For the purpose, phase shifting is applied in a continuous mode. The proposed continuous phase-scanning method is proposed to apply the phase-extraction principle on a specific heterodyne frequency generated from multiple cycles of 2π-scanning by the uniform translation of PZT-driven stage. As a result, inherent drawbacks of conventional PSI algorithms, such as nonlinearity errors of PZT, measurement speed, complexity of phase analysis algorithm, can be overcome effectively. The experimental results about surface measurement of 1" spherical concave mirror show that superior phase reconstruction performance with good quality can be achieved even under severe vibration circumstances simulated by target excitation along a lateral direction.

Date Published: 10 September 2009
PDF: 9 pages
Proc. SPIE 7432, Optical Inspection and Metrology for Non-Optics Industries, 74320O (10 September 2009); doi: 10.1117/12.825793

Published in SPIE Proceedings Vol. 7432:
Optical Inspection and Metrology for Non-Optics Industries
Peisen S. Huang; Toru Yoshizawa; Kevin G. Harding, Editor(s)