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Proceedings Paper

Very high resolution 3D surface scanning using multi-frequency phase measuring profilometry
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Paper Abstract

Structured light projection is one of the most accurate non-contact methods for scanning surface topologies. The field of view of such a scan may range from millimeters to several meters. One of the most precise and robust methods of structured light is Phase Measuring Profilometry. This method utilizes a sinusoidal pattern that is laterally shifted across a surface. An image is captured at uniform intervals and the “phase” is recovered for each pixel position by correlating across the shifted patterns. In general, the more pattern shifts and the higher the spatial frequency, the more accurate the depth measurement becomes, at each pixel location. However, with a high frequency, ambiguity errors can occur, so a dual frequency approach is commonly used where a low frequency pattern is used for non-ambiguous depth, followed by high frequency pattern. The low frequency result is used to unwrap the high frequency to yield a non-ambiguous and precise phase. If the high frequency is too high, then ambiguity errors will occur. The solution is a multi-frequency method. We present experimental results for several variations of the multi-frequency approach yielding accuracies of 0.127mm standard deviation in depth with 0.92mm pixel spacing. With consumer camera mega pixel technology this equates to a 0.127mm deviation over a field of view of 2 to 3 meters. To achieve this level of accuracy also requires calibration for radial and perspective distortions. Applications for this technology include non-contact surface measurement and robotic and computer vision.

Paper Details

Date Published: 19 May 2005
PDF: 10 pages
Proc. SPIE 5798, Spaceborne Sensors II, (19 May 2005); doi: 10.1117/12.603832
Show Author Affiliations
Veera Ganesh Yalla, Univ. of Kentucky (United States)
Laurence G. Hassebrook, Univ. of Kentucky (United States)

Published in SPIE Proceedings Vol. 5798:
Spaceborne Sensors II
Peter Tchoryk Jr.; Brian Holz, Editor(s)

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