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Proceedings Paper

Electronic fringe projection for profiling large surfaces
Author(s): Robert C. Chang; Christopher W. Carroll
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Paper Abstract

An experimental fringe projection system, composed of a video projector, a CCD camera and a reference plane, has been developed for profiling large diffuse surface. A test object is placed on the reference plane, which is considered to be at zero height. The video projector projects PC generated electronic images as fringes on the surface of the test object. The CCD camera is then used to acquire images of the test surface without viewing through a reference grating. The only constraint on the system's optical setup is non-parallel projecting and viewing axes. This system is easy to setup, adaptable for inspecting difficult sized test objects, and offers high precision phase shifting for phase measurement. However, flexibility in placement of system components introduces geometrical distortions in images of test surfaces, such as translation, rotation, skewing, scaling and perspective. As a result, surface contours can not be determined simply from phases and periods of projected fringes. The current development utilizes a simple calibration procedure to establish quantitative linear geometrical relationships between the camera, projector and reference plane. Those relationships, coupled with phase measurement, are used for determining true perspective surface contours.

Paper Details

Date Published: 6 January 1994
PDF: 9 pages
Proc. SPIE 2348, Imaging and Illumination for Metrology and Inspection, (6 January 1994); doi: 10.1117/12.198838
Show Author Affiliations
Robert C. Chang, Aluminum Co. of America (United States)
Christopher W. Carroll, Carnegie Mellon Research Institute (United States)

Published in SPIE Proceedings Vol. 2348:
Imaging and Illumination for Metrology and Inspection
Donald J. Svetkoff, Editor(s)

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