Paper
20 November 1989 3-D Displacement Analysis Using Oblique Axis Speckle Photography
E. W. Smith, Y. S. Tan, Y. M. He
Author Affiliations +
Abstract
It is usual, in speckle photography, to set the optical axis of the photographic lens so that it is perpendicular to the surface being investigated. However if the photographic lens is set with its optical axis at an angle to the object surface then it is shown that the accuracy of separating out the in-plane and out-of-plane displacements can be improved. A further benefit is that the whole visual field of the photographic lens can be studied whether the object itself is flat or has a 3-D surface profile. This means that speckle photography can be applied to objects of any shape and of considerable size. Firstly the principle and theory of the oblique axis method is explained. In particular the method of correct focusing is shown; because of this the technique is not possible with simple 35 mm SLR cameras where lens and film planes do not have the necessary movements for differential focusing, none the less the potential of a mono-rail plate camera can be full realized. Secondly the validity of the technique will be seen by presenting results of tests on a simple structure. Finally it will be shown, using automatic fringe analysis, that the method can be applied to large 3-D structures, such as a machine tool.
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
E. W. Smith, Y. S. Tan, and Y. M. He "3-D Displacement Analysis Using Oblique Axis Speckle Photography", Proc. SPIE 1163, Fringe Pattern Analysis, (20 November 1989); https://doi.org/10.1117/12.962799
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KEYWORDS
Speckle

Photography

Cameras

Fringe analysis

Holographic interferometry

Image processing

Image filtering

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