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Proceedings Paper

Full-field surface profiling using dynamic projected grids
Author(s): Robert J. Beeson
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Paper Abstract

The dynamic grid projection method for measuring 3-dimensional surface profiles utilizes a rotating grid as the structured light source. This technique has several advantages over other triangulation methods, such as the ability to determine the fringe order (and therefore the range) of each image pixel independently, with no relative motion between the sensor and test object. Because of the high data rate required to sample the signal from a rotating grid, dynamic fringe projection methods have typically been limited to single-point measurements using photodiode sensors. Also, the complex signal analysis algorithms used have limited the resolution and speed of the technique. This paper describes a prototype system developed with a photodiode sensor array imager and simplified digital signal processing algorithms. The use of a photodiode array gives the imaging system sufficient bandwidth to measure significant regions of the surface simultaneously. By extracting only the essential elements of the data from each pixel's output, such as the number of fringes crossed and the crossing with the maximum duration, an accurate surface measurement can be made with a simple search algorithm. The theoretical resolution of the system is limited by the speed of the imaging array, the accuracy of the grid's rotation, and the imaging optics.

Paper Details

Date Published: 10 December 1997
PDF: 6 pages
Proc. SPIE 3204, Three-Dimensional Imaging and Laser-based Systems for Metrology and Inspection III, (10 December 1997); doi: 10.1117/12.294442
Show Author Affiliations
Robert J. Beeson, Southwest Research Institute (United States)

Published in SPIE Proceedings Vol. 3204:
Three-Dimensional Imaging and Laser-based Systems for Metrology and Inspection III
Kevin G. Harding; Donald J. Svetkoff, Editor(s)

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