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Optical Engineering

Systematic pointing errors with retroreflective targets
Author(s): Roland M. Zumbrunn
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Paper Abstract

Accurate target detection is fundamental to many industrial measuring applications. One type of target uses retroreflective material for defining object surface points. In a photogrammetric procedure camera at different positions illuminate these targets, which are imaged onto the CCD array. By intersecting all the lines of sight, the targets are fixed in space. In the past, accuracy improvements have been concentrated mainly on algorithms or sensor calibration, such as better modeling of optical and electronic distortions, and less effort has been spent on potential targeting problems. It is conventionally assumed that the target center is physically fixed and independent of the angle a between the target normal and the line of sight. The author investigates this assumption in the case of retroreflective targets. Tests have revealed a systematic shift of the target center from -30 to +30 μm normal to the line of sight, when the target is viewed from different directions, i.e. -40 deg ≤ α ≤ +40 deg. There is no shift seen for punched targets.

Paper Details

Date Published: 1 September 1995
PDF: 5 pages
Opt. Eng. 34(9) doi: 10.1117/12.201812
Published in: Optical Engineering Volume 34, Issue 9
Show Author Affiliations
Roland M. Zumbrunn, Leica Heerbrugg AG (Switzerland)


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