Most 3D laser scanners are based on 3D optical triangulation algorithms, where the location of each 3D point is estimated as the intersection of a camera ray and a plane of light projected by a laser line generator. Since a physical laser line generator projects a sheet of light of finite thickness, inaccurate measurement and errors result from assuming that the plane of light is infinitesimally thin. We propose a new mathematical formulation for 3D optical triangulation based on interval arithmetic, where 3D points are only determined within certain bounds along the camera rays, and multiple measurements are used to tighten these bounds. We propose the Line Segment Cloud as an alternative surface representation to visualize the measurement errors within the proposed framework. We introduce the Iterative Line Segment Tightening algorithm to convert line segment clouds to point clouds, as a preprocessing step prior to surface reconstruction. We describe how to construct a low cost laser line 3D scanner, where the camera is fixed with respect to the object and the laser line generator is mounted on a high resolution motion platform. We describe a GPU-based implementation where the large number of captured images are processed in real time. Finally, we present some experimental results.
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Vision ray metrology: a new versatile tool for the metrology and alignment of optics
A novel Vision ray metrology technique is reported that estimates the geometric wavefront of a measurement sample using the sample-induced deflection in the vision rays. Vision ray techniques are known in the vision community to provide image formation models even when conventional camera calibration techniques fail. This work extends the use of vision rays to the area of optical metrology. In contrast to phase measuring deflectometry, this work relies on differential measurements, and hence, the absolute position and orientation between target and camera do not need to be known. This optical configuration significantly reduces the complexity of the reconstruction algorithms. The proposed vision ray metrology system does not require mathematical optimization algorithms for calibration and reconstruction – the vision rays are obtained using a simple 3D fitting of a line.
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- NSF-PAR ID:
- 10429453
- Date Published:
- Journal Name:
- Proceedings Volume 12223, Interferometry XXI; 1222304 (2022) https://doi.org/10.1117/12.2634327 Event: SPIE Optical Engineering + Applications, 2022, San Diego, California, United States
- Volume:
- 29
- Issue:
- 26
- Page Range / eLocation ID:
- 22
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1117/12.2634327
