1 March 1974 Speckle-Shearing Interferometric Camera -- A Tool For Measurement Of Derivatives Of Surface-Displacement
Author Affiliations +
Abstract
A camera having a lens with two apertures and equipped with a shearing mechanism is employed to image a specimen which is illuminated by coherent light. With this arrangement, the speckle from one point on the surface is allowed to interfere with the speckle from a neighboring point so that a speckle-grid pattern may be detected in the image plane. By double-exposure or real-time techniques, the speckle-grid pattern corresponding to the deformed state of the specimen is added to the speckle-grid pattern corresponding to the undeformed state of the specimen. The resulting mechanical interference produces a moire-fringe pattern which depicts derivatives of surface-displacements. The camera will be referred to as "Speckle-shearing Interferometric Camera". Three applications of the speckle-shearing interferometric camera are described: (1) mea-surement of slopes of structural deflections, (2) in-plane strain measurement, (3) vibration analy-sis. Experimental demonstrations for each case of the applications are presented. Although the speckle-shearing interferometric camera is based on interferometric principles, it overcomes several of the limitations associated with holographic and speckle interferometries, namely: (1) the setup is simple and does not re-quire laborous alignment of optical components, (2) it does not require stringent mechanical and ambient atmospheric stabilities, (3) coherent requirements of light are greatly relaxed, (4) the sensitivity is greatly reduced, and (5) it does not require differentiation to obtain strains.
© (1974) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yau Y. Hung, Yau Y. Hung, Charles E. Taylor, Charles E. Taylor, } "Speckle-Shearing Interferometric Camera -- A Tool For Measurement Of Derivatives Of Surface-Displacement", Proc. SPIE 0041, Developments in Laser Technology II, (1 March 1974); doi: 10.1117/12.953850; https://doi.org/10.1117/12.953850
PROCEEDINGS
8 PAGES


SHARE
RELATED CONTENT

Versatile electronic speckle pattern interferometry
Proceedings of SPIE (June 29 1998)
Real-Time Moire Holography
Proceedings of SPIE (August 19 1986)
Speckle Shearing Interferometry And Its Application
Proceedings of SPIE (December 12 1983)
Detection of vibrating sound fields using speckle shearography
Proceedings of SPIE (September 27 1999)

Back to Top