1 May 2003 Unified approach for holography and shearography in surface deformation measurement and nondestructive testing
Y.Y. Hung, HuaiMin Shang, Lian Xiang Yang
Author Affiliations +
Holography and shearography are two useful whole-field noncontacting optical tools for nondestructive flaw detection and precision measurements. Holography serves as a displacement transducer since it gives direct measurements on displacements whereas shearography serves as a strain gage since it gives direct measurements on displacement gradients. This paper views holography and shearography and their variations as a single optical technique having the same basic mathematical formulation and instrumentation. A key optical component used in both techniques is a doubly-refractive prism that combines two angularly separated laser rays to interfere at near collinearity, thereby permitting the use of a low-resolution CCD camera for recording the interference pattern. Shearography uses a doubly-refractive prism with small image shearing so that two neighboring points on the test surface are brought to interfere at the image plane of the camera, whereas holography, on the other hand, uses a doubly-refractive prism with large image shearing so that light scattered from two different objects—a test object and a reference surface (serving as a reference beam)—are brought to interfere at the image plane of the camera. Hence, testing and measurements made using holography may also be made using shearography, and vice versa.
©(2003) Society of Photo-Optical Instrumentation Engineers (SPIE)
Y.Y. Hung, HuaiMin Shang, and Lian Xiang Yang "Unified approach for holography and shearography in surface deformation measurement and nondestructive testing," Optical Engineering 42(5), (1 May 2003). https://doi.org/10.1117/1.1567263
Published: 1 May 2003
Lens.org Logo
CITATIONS
Cited by 59 scholarly publications.
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Holography

Shearography

Fringe analysis

Speckle pattern

Digital holography

Prisms

Cameras

Back to Top