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Proceedings Paper

Surface inspection system for carriage parts
Author(s): Berend Denkena; Wolfram Acker
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Paper Abstract

Quality standards are very high in carriage manufacturing, due to the fact, that the visual quality impression is highly relevant for the purchase decision for the customer. In carriage parts even very small dents can be visible on the varnished and polished surface by observing reflections. The industrial demands are to detect these form errors on the unvarnished part. In order to meet the requirements, a stripe projection system for automatic recognition of waviness and form errors is introduced1. It bases on a modified stripe projection method using a high resolution line scan camera. Particular emphasis is put on achieving a short measuring time and a high resolution in depth, aiming at a reliable automatic recognition of dents and waviness of 10 μm on large curved surfaces of approximately 1 m width. The resulting point cloud needs to be filtered in order to detect dents. Therefore a spatial filtering technique is used. This works well on smoothly curved surfaces, if frequency parameters are well defined. On more complex parts like mudguards the method is restricted by the fact that frequencies near the define dent frequencies occur within the surface as well. To allow analysis of complex parts, the system is currently extended by including 3D CAD models into the process of inspection. For smoothly curved surfaces, the measuring speed of the prototype is mainly limited by the amount of light produced by the stripe projector. For complex surfaces the measuring speed is limited by the time consuming matching process. Currently, the development focuses on the improvement of the measuring speed.

Paper Details

Date Published: 21 April 2006
PDF: 8 pages
Proc. SPIE 6198, Photonics in the Automobile II, 619801 (21 April 2006); doi: 10.1117/12.662572
Show Author Affiliations
Berend Denkena, Univ. Hannover (Germany)
Wolfram Acker, Univ. Hannover (Germany)

Published in SPIE Proceedings Vol. 6198:
Photonics in the Automobile II
Patrick P. Meyrueis; Thomas P. Pearsall, Editor(s)

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