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Proceedings Paper

Metric projector camera calibration for measurement applications
Author(s): Jan W. Horbach; Thao Dang
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Paper Abstract

Structured light is widely used for shape measurement of surfaces using the triangulation principle. To fulfill this task, precise information about the optical path is necessary. We propose a novel method for the overall calibration of a setup consisting of a structured light source, a projection screen and a camera. As computer controlled video projectors become cheaper and cheaper, it is reasonable to use these off-the-shelf devices for measurement applications. However, to achieve high accuracy with standard components, a precise calibration of the measurement system is indispensable. Absolute position and orientation of the camera, the projector and the projection screen has to be known. Furthermore, intrinsic calibration of both the camera and the projector is necessary. After acquiring a large set of data points using a versatile phase encoding technique, we estimate the optimal parameters using a bundle adjustment technique. We consider all extrinsic and intrinsic parameters for the optical mapping including a distortion model for the projector and for the camera, respectively. We propose a method which ensures complete knowledge about the optical mapping of each ray observed by the camera. The proposed metric calibration method has also importance for other measurement applications as e.g. shape reconstruction of specular surfaces. Hereby structured light patterns are projected on the screen, and their reflection on the specular surface is observed by the camera.

Paper Details

Date Published: 12 October 2006
PDF: 11 pages
Proc. SPIE 6382, Two- and Three-Dimensional Methods for Inspection and Metrology IV, 63820G (12 October 2006); doi: 10.1117/12.686000
Show Author Affiliations
Jan W. Horbach, Univ. Karlsruhe (Germany)
Thao Dang, Univ. Karlsruhe (Germany)

Published in SPIE Proceedings Vol. 6382:
Two- and Three-Dimensional Methods for Inspection and Metrology IV
Peisen S. Huang, Editor(s)

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