This paper develops a set of projection Moiré system. It projects the grating onto the surface of specimen and forms grid lines of which the pitch is adjustable on large area through light source and projection grating. At the same time, the imaging system images the grid lines precisely onto the reference grating and then the Moiré fringes are formed. The modulation of out-of-plane displacement to grid lines transform into the distortion of Moiré fringes. The greatest advantage of this projection Moiré system is that what the CCD camera captures is the Moiré fringes, not the gird lines. The Moiré fringes can magnify the variation of out-of-plane displacement of the specimen with no distortion and the measuring resolution is improved a lot. Besides, this system is appropriate for large area measurement by using a wide-angle lens in imaging system. The full-field out-of-plane displacement can be acquired through image processing. The measuring resolution of this system can reach 10μm on a large area of 3m*3m.

Date Published: 4 March 2015
PDF: 8 pages
Proc. SPIE 9302, International Conference on Experimental Mechanics 2014, 93021Z (4 March 2015); doi: 10.1117/12.2084679

Published in SPIE Proceedings Vol. 9302:
International Conference on Experimental Mechanics 2014
Chenggen Quan; Kemao Qian; Anand Asundi; Fook Siong Chau, Editor(s)