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Proceedings Paper

Combined stereovision and phase shifting method: a new approach for 3D shape measurement
Author(s): Xu Han; Peisen Huang
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Paper Abstract

A new method, which combines the stereovision and phase shifting techniques, is proposed for more accurate 3-D shape measurement. This method uses two cameras and one projector and can eliminate errors caused by inaccurate phase measurement, for example, periodic errors due to the nonlinearity of the projector's gamma curve. The two cameras are set up for stereovision. The projector is used to project phase-shifted fringe patterns onto the object twice with the fringe patterns rotated by 90 degrees in the second time. Fringe images are taken by the two cameras from different directions simultaneously. The resulting phase maps are used to assist stereo matching at the pixel level. The coordinates of the object surface are calculated based on triangulation. Since the phase value at each pixel is used to assist stereo matching only, it does not have to be accurate. This means that the projector does not need to be calibrated, which simplifies the system calibration. Errors due to inaccurate phase measurement are significantly reduced because the two cameras produce phase maps with the same phase errors. This combined method is better than stereovision method alone because it provides higher resolution and easier stereo matching. It is better than the phase shifting method alone because it eliminates the need of accurate phase measurement in order to ensure high measurement accuracy. Experimental results and comparisons with the typical phase shifting method are presented to show the effectiveness and advantages of this newly proposed method.

Paper Details

Date Published: 17 June 2009
PDF: 8 pages
Proc. SPIE 7389, Optical Measurement Systems for Industrial Inspection VI, 73893C (17 June 2009); doi: 10.1117/12.828223
Show Author Affiliations
Xu Han, Stony Brook Univ. (United States)
Peisen Huang, Stony Brook Univ. (United States)


Published in SPIE Proceedings Vol. 7389:
Optical Measurement Systems for Industrial Inspection VI
Peter H. Lehmann, Editor(s)

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