We previously proposed the integrated phase-shifting method for the grating projection method using a Ronchi grating to display the height distribution of an object in real-time. The method uses a correlation between a grating brightness with a rectangular distribution and a rectangular function. The brightness of the phase-shifted fringe pattern is integrated on a CCD sensor of a camera during one exposure time and the integrated values are recorded. The theory uses the integration of the brightness at each pixel point during one exposure-time. In the present study, this method is extended to fringe pattern analysis with a cosinusoidal brightness distribution. A theory of the phase-shifting method for high-speed phase shifting is proposed. By integrating the brightness during one exposure time, the equation is modified to obtain accurate phase values. The analyzed phase values from continuous four images immediately before the last exposure time are obtained at very exposure time, i.e. every 1/30 seconds. The application to small displacement analysis of a cantilever and a micro- accelerometer are shown.

Date Published: 13 August 1999
PDF: 8 pages
Proc. SPIE 3744, Interferometry '99: Techniques and Technologies, (13 August 1999); doi: 10.1117/12.357700

Published in SPIE Proceedings Vol. 3744:
Interferometry '99: Techniques and Technologies
Malgorzata Kujawinska; Mitsuo Takeda, Editor(s)