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Optical Engineering

3-D metrology system with internal calibration
Author(s): Daniel Härter; Claas Müller; Holger Reinecke
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Paper Abstract

3-D metrology systems are used from examination and qualification of micro manufacturing techniques to reverse engineering of microstructures. For this purpose, the generation of capable and reliable 3-D coordinates in large numbers is essential. Combining classical triangulation with a new technique of calibrating measurement labels results in high rates of reliable 3-D metrology data. The triangulation setup consists of a stereomicroscope mounted on a 5-axis-gantry to generate all necessary points of view. Measurement labels are projected through one port of the stereomicroscope while their positions are localized through the second port. Providing a calibration rule is defined, the measurement system assigns each localized position to an absolute coordinate. For registration purposes, measurement labels are projected on a semitransparent mirror. Localizing measurement labels simultaneously with an observation and a calibration camera in connection with the working distance defines the calibration rule. By modifying the working distance between calibration camera and stereomicroscope, the measurement volume is scanned. The grid of the calibration camera chip acts as a measurement standard for the measurement labels. This approach features the spatial registration of a huge amount of measurement labels, covering the measurement volume, without building up the optical model of the imaging in a short time.

Paper Details

Date Published: 1 January 2011
PDF: 7 pages
Opt. Eng. 50(1) 013604 doi: 10.1117/1.3530130
Published in: Optical Engineering Volume 50, Issue 1
Show Author Affiliations
Daniel Härter, Albert-Ludwigs-Univ. Freiburg (Germany)
Claas Müller, Albert-Ludwigs-Univ. Freiburg (Germany)
Holger Reinecke, Albert-Ludwigs-Univ. Freiburg (Germany)

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