The determination of 3-D displacement and strain by holographic interferometry for industr'ial applications is a problem still not resolved satisfactorily. Important requirements are: 1) simple optical arrangement requiring only one hologram recording, 2) fully automated fringe evaluation and data processing. The proposed arrangement with quasi-heterodyne (phase shifting) fringe interpolation and video-electronic detection offers fast and automated phase measurement with high accuracy. The 3-D information about the deformation is obtained by moving the TV-camera behind the hologram plate to get different directions of observation. If the object shape is known, the effects of image distortion due to perspective can be corrected by appropriate interpolation of the measured interference phases. In this paper, the optical setup and the data acquisition system will be described. The calculation of vector displacement and strain, including correction of the distortion by perspective, are discussed in detail. Finally, experimental results with an estimation of the accuracy for displacement and strain will be reported.

Date Published: 16 July 1986
PDF: 8 pages
Proc. SPIE 0599, Optics in Engineering Measurement, (16 July 1986); doi: 10.1117/12.952366

Published in SPIE Proceedings Vol. 0599:
Optics in Engineering Measurement
William F. Fagan, Editor(s)