Optical Measuring Technique For Small Scale Water Surface Waves

Bernd Jahne; Stefan Waas

doi:10.1117/12.961496

6 October 1989 Optical Measuring Technique For Small Scale Water Surface Waves

Bernd Jahne, Stefan Waas

Proceedings Volume 1129, Advanced Optical Instrumentation for Remote Sensing of the Earth's Surface from Space; (1989) https://doi.org/10.1117/12.961496
Event: 1989 International Congress on Optical Science and Engineering, 1989, Paris, France

Abstract

Two active optical techniques have been developed to measure the spatio-temporal structure of small scale waves with wavelength in the range of 2mm to 20 cm. One technique, the imaging slope gauge (ISG), is based on light refraction at the water surface and records im-age sequences of the wave slope at a maximum area of 1 m2. With the other technique, the reflective stereo slope gauge (RSSG), the water surface is illuminated from above by a monochromatic light source. Two CCD-cameras take stereo image sequences of the specular reflexes returned by the water surface. The wave height is calculated from the parallax between the right and left images with a fast multi-grid algorithm. This technique is also suitable for measurements in the field. The new instruments have successfully been used in the world's largest wind/wave facilities (Delft Hydraulics, The Netherlands) in the frame of the international VIERS-1 project. This project inves-tigates the physical mechanisms of radar scatterometry. Besides our research groups the VIERS-1 participants are the Physics and Electronics Laboratory of the Organization for Applied Research (FEL-TNO), Technical Univ. of Delft, the Royal Netherlands Meteorological Inst. (KNMI), Delft Hydraulics (WL), and the Directorate Tidal Waters of the Department of Harbors and Public Works (RWS-DGW). Two-dimensional wavenumber spectra, two-dimensional slope and one-dimensional height distributions calculated from the data of the two instruments are discussed.

Citation Download Citation

Bernd Jahne and Stefan Waas "Optical Measuring Technique For Small Scale Water Surface Waves", Proc. SPIE 1129, Advanced Optical Instrumentation for Remote Sensing of the Earth's Surface from Space, (6 October 1989); https://doi.org/10.1117/12.961496

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