Heidelberg 2006 – scientific programme

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UP: Umweltphysik

UP 9: Poster: Hydrosph
äre

UP 9.5: Poster

Tuesday, March 14, 2006, 14:00–16:00, C

Imaging System for Simultaneous Slope and Height Measurements of Short Wind-Waves — •Roland Rocholz and Bernd Jähne — Institut für Umweltphysik, Heidelberg

A novel imaging system for the measurement of short wind waves named imaging slope/height gauge (ISHG) is described. It is designed for the simultaneous measurement of wave slopes and wave heights with high spatio temporal resolution and a reconstruction of the moving water surface. Gas-exchange experiments and studies of the fluid dynamics at wind wave tanks are the framework of this effort. The technique is based on slope measurement by means of refraction, height measurement using infrared absorption, telecentric illumination, and telecentric imaging. The setup utilizes a programmable, area extended light source and a high speed camera with more than 1000 frames/s. In order to measure both components of the wave slope and the water height, the position-dependent intensity of the light source is varying between four distinct states. The telecentric illumination suppresses the influence of height variations on slope measurement. The telecentric imaging keeps the image magnification constant, even in the presence of higher wave amplitudes.