Another look at volume self-calibration: calibration and self-calibration within a pinhole model of Scheimpflug cameras
| Autor: | Yves Le Sant, Philippe Cornic, Frédéric Champagnat, Guy Le Besnerais, Cédric Illoul, Benjamin Leclaire, Adam Cheminet |
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| Rok vydání: | 2016 |
| Předmět: |
Adapter (computing)
Computer science business.industry Applied Mathematics Scheimpflug principle Astrophysics::Instrumentation and Methods for Astrophysics 01 natural sciences 010305 fluids & plasmas 010309 optics Optics 0103 physical sciences Calibration Pinhole camera model Vector field Pinhole (optics) business Instrumentation Engineering (miscellaneous) Global optimization Camera resectioning |
| Zdroj: | Measurement Science and Technology. 27:094004 |
| ISSN: | 1361-6501 0957-0233 |
| DOI: | 10.1088/0957-0233/27/9/094004 |
| Popis: | We address calibration and self-calibration of tomographic PIV experiments within a pinhole model of cameras. A complete and explicit pinhole model of a camera equipped with a 2-tilt angles Scheimpflug adapter is presented. It is then used in a calibration procedure based on a freely moving calibration plate. While the resulting calibrations are accurate enough for Tomo-PIV, we confirm, through a simple experiment, that they are not stable in time, and illustrate how the pinhole framework can be used to provide a quantitative evaluation of geometrical drifts in the setup. We propose an original self-calibration method based on global optimization of the extrinsic parameters of the pinhole model. These methods are successfully applied to the tomographic PIV of an air jet experiment. An unexpected by-product of our work is to show that volume self-calibration induces a change in the world frame coordinates. Provided the calibration drift is small, as generally observed in PIV, the bias on the estimated velocity field is negligible but the absolute location cannot be accurately recovered using standard calibration data. |
| Databáze: | OpenAIRE |
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