Triangulation methods for height profile measurements on instationary water surfaces

Abstract

The precise measurement of water surface models or profiles plays an important role in experimental hydromechanics. Conventional gauge-based techniques often come with a large instrumental effort and a limited spatial resolution. The paper shows an e‰cient non-contact photogrammetric technique for the measurement of water-surface profiles, which is based on an extension of the well-known laser light sheet projection technique. While the original laser lightsheet triangulation technique is limited to surfaces with di¤use reflection properties, the developed technique is capable of measuring on reflecting instationary surfaces. This article presents the basic principle, potential and limitations of the method. Several evolution steps of the system with di¤erent applicability and di¤erent complexity are shown. A double projection plane system capable of simultaneously measuring water surface height and tilt profiles marks the ceiling of the development. Besides the geometrical models of different levels of complexity, system calibration procedures are described. The applicability of the techniques and their accuracy potential are shown in several practical tests.