title: Underwater 3D Surface Measurement Using Fringe Projection Based Scanning Devices.
abstract: In this work we show the principle of optical 3D surface measurements based on the fringe projection technique for underwater applications. The challenges of underwater use of this technique are shown and discussed in comparison with the classical application. We describe an extended camera model which takes refraction effects into account as well as a proposal of an effective, low-effort calibration procedure for underwater optical stereo scanners. This calibration technique combines a classical air calibration based on the pinhole model with ray-based modeling and requires only a few underwater recordings of an object of known length and a planar surface. We demonstrate a new underwater 3D scanning device based on the fringe projection technique. It has a weight of about 10 kg and the maximal water depth for application of the scanner is 40 m. It covers an underwater measurement volume of 250 mm × 200 mm × 120 mm. The surface of the measurement objects is captured with a lateral resolution of 150 μm in a third of a second. Calibration evaluation results are presented and examples of first underwater measurements are given.
authors.affiliation: Fraunhofer Institute Applied Optics and Precision Engineering, Albert-Einstein-Str. 7, D-07745 Jena, Germany. Christian.braeuer-burchardt@iof.fraunhofer.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Bräuer-Burchardt
authors.affiliation: Fraunhofer Institute Applied Optics and Precision Engineering, Albert-Einstein-Str. 7, D-07745 Jena, Germany. matthias.heinze@iof.fraunhofer.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Heinze
authors.affiliation: Fraunhofer Institute Applied Optics and Precision Engineering, Albert-Einstein-Str. 7, D-07745 Jena, Germany. ingo.schmidt@iof.fraunhofer.de.
authors.forename: Ingo
authors.initials: I
authors.lastname: Schmidt
authors.affiliation: Fraunhofer Institute Applied Optics and Precision Engineering, Albert-Einstein-Str. 7, D-07745 Jena, Germany. peter.kuehmstedt@iof.fraunhofer.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Kühmstedt
authors.affiliation: Fraunhofer Institute Applied Optics and Precision Engineering, Albert-Einstein-Str. 7, D-07745 Jena, Germany. gunther.notni@iof.fraunhofer.de.|Technical University Ilmenau, Ehrenbergstraße 29, D-98693 Ilmenau, Germany. gunther.notni@iof.fraunhofer.de.
authors.forename: Gunther
authors.initials: G
authors.lastname: Notni
mesh_terms: D000465:Algorithms; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D056127:Hydrobiology; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods*; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water
keywords: fringe projection; underwater 3D-scanner; underwater stereo camera calibration