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ISSN 2029-7092 online
ISBN 978-609-457-690-4 CD
ISBN 978-609-457-640-9
 Environmental Protection

Damian Wierzbicki, Michalina Wilińska

Liquid crystal tunable filters in detecting water pollution

Conference Information: 9th International Conference on Environmental Engineering, MAY 22-23, 2014 Vilnius, LITHUANIA
Source: ICEE-2014 - International Conference on Environmental Engineering
Book Series: International Conference on Environmental Engineering (ICEE) Selected papers
ISSN: ISSN 2029-7092 online
ISBN: 978-609-457-640-9 / 978-609-457-690-4 CD
Year: 2014
Publisher: Vilnius Gediminas Technical University Press Technika

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In this article a methodology for determining the transmission of two electronically tunable interference filters Varispec CRI-VIS and CRI-SNIR had been described. The aim of the research was to determine the filter transmission values and to compare them with the results provided by the filter’s producer. The tested interference filters are built with the intent of being integrated with panchromatic video cameras (400–1100 nm). As a result of this integration, hyperspectral sensors can be created. The acquired data could then be used to determine spectral reflectance characteristics, and on that basis, a methodology of the detection of physical, chemical and biological pollutants in rivers, coastal zones and flood areas will be elaborated. The precise determination of the filters transmission values is necessary to establish the correct exposure parameters. Thanks to a correct methodology of data acquisition, the collected images could be used for qualitative and quantitative analyses of surface water pollutants. Within the framework of the presented research, laboratory measurements of the filter transmissions were carried out for the CRI-SNIR-10-20 filter (for the interval from 650 nm to 1100 nm) and the CRI-VIS-20-20 filter (for the interval from 400 nm to 720 nm). The main concept of the research was to calibrate a spectroradiometer using a reference panel and then to perform a series of measurements of the light transmitted through the filter which had been tuned to a specific wavelength. The measurements were conducted using Field Spec 3, Field Spec 4 Wide-Res spectroradiometers and a JASCO V670 spectrophotometer. In addition, using a goniometer, an analysis of the influence of the measurement station geometry on the filters transmission values were carried out.

Keywords: environmental protection; water engineering; Liquid crystal tunable filters (LCTF); transmission; water pollution.

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