22 June 2015 System for deflection measurements of floating dry docks
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In this paper we introduce a system for deflection measurement of floating dry docks. The system contains two measurement channels observing opposite directions of the dock. It also includes set of reference marks, an industrial computer and a display. Each channel contains CMOS camera with long focal-length lens. Reference marks are implemented as IR LED arrays with 940 nm working wavelength for better performance within bad weather conditions (e.g. fog, rain, high humidity etc.). In the paper we demonstrate results of an analysis of different optical schemes for coupling the oppositely directed channels of the measurement unit and show that the scheme with two image sensors with separated lenses is an optimal option, because it allows usage of nonequidistant location of reference marks and demonstrates the least value of parasitic shift caused by rotations of the measuring unit. The developed system was tested both on specially-designed setup and in real infrastructure of a floating dry dock. The conducted tests proved that a measuring error of the system is smaller than ± 1.5 mm within the measurement range of ± 150 mm when deflection of 100 m dock is measured. Obtained results showed that the system demonstrates an ability to work in a harsh environment including poor weather conditions.
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Alexey A. Gorbachev, Alexey A. Gorbachev, Anton V. Pantyushin, Anton V. Pantyushin, Mariya G. Serikova, Mariya G. Serikova, Valery V. Korotaev, Valery V. Korotaev, Aleksandr N. Timofeev, Aleksandr N. Timofeev, } "System for deflection measurements of floating dry docks", Proc. SPIE 9525, Optical Measurement Systems for Industrial Inspection IX, 95254C (22 June 2015); doi: 10.1117/12.2184925; https://doi.org/10.1117/12.2184925


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