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Visual Measurement of Water Level under Complex Illumination Conditions

Image-based water level measurement is a visual-sensing technique which automatically inspects the reading of the water line via image processing instead of the human eye. It can be realized easily on an existing video surveillance system and has advantages like low cost, non-contact, as well as res...

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Autores principales: Zhang, Zhen, Zhou, Yang, Liu, Haiyun, Zhang, Lili, Wang, Huibin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6806611/
https://www.ncbi.nlm.nih.gov/pubmed/31554301
http://dx.doi.org/10.3390/s19194141
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author Zhang, Zhen
Zhou, Yang
Liu, Haiyun
Zhang, Lili
Wang, Huibin
author_facet Zhang, Zhen
Zhou, Yang
Liu, Haiyun
Zhang, Lili
Wang, Huibin
author_sort Zhang, Zhen
collection PubMed
description Image-based water level measurement is a visual-sensing technique which automatically inspects the reading of the water line via image processing instead of the human eye. It can be realized easily on an existing video surveillance system and has advantages like low cost, non-contact, as well as results that are verifiable. It has the potential to be widely used in flood and waterlogging monitoring, while facing the challenge that water-line detection under complex natural or artificial illumination conditions is quite difficult in field applications. To handle this problem, a method is proposed assuming that the water line is generally located on the row with the largest local change of gray or edge features in the image of the water gauge. The water line is determined by coarse-to-fine detection of the position of the maximum mean difference (MMD) of the horizontal projections of gray and edge images. Image-based flow-level measurement systems were developed at two measurement sites. In situ comparative experiments were conducted with the float-type stage gauge and other image-based methods. The results show that the fusion of gray and edge features can overcome the shortcomings of single feature methods under complex illumination conditions such as dim light, glares, shadows and artificial night lighting. A coarse-to-fine strategy utilizes the periodicity of the surface pattern distribution of the standard bicolor water gauge, which improves the reliability of water-line detection. The resolution and accuracy of water-level measurement are 1 mm and 1 cm, respectively. In particular, the MMD value is efficient at identifying extremely unfavorable conditions and reducing gross errors.
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spelling pubmed-68066112019-11-07 Visual Measurement of Water Level under Complex Illumination Conditions Zhang, Zhen Zhou, Yang Liu, Haiyun Zhang, Lili Wang, Huibin Sensors (Basel) Article Image-based water level measurement is a visual-sensing technique which automatically inspects the reading of the water line via image processing instead of the human eye. It can be realized easily on an existing video surveillance system and has advantages like low cost, non-contact, as well as results that are verifiable. It has the potential to be widely used in flood and waterlogging monitoring, while facing the challenge that water-line detection under complex natural or artificial illumination conditions is quite difficult in field applications. To handle this problem, a method is proposed assuming that the water line is generally located on the row with the largest local change of gray or edge features in the image of the water gauge. The water line is determined by coarse-to-fine detection of the position of the maximum mean difference (MMD) of the horizontal projections of gray and edge images. Image-based flow-level measurement systems were developed at two measurement sites. In situ comparative experiments were conducted with the float-type stage gauge and other image-based methods. The results show that the fusion of gray and edge features can overcome the shortcomings of single feature methods under complex illumination conditions such as dim light, glares, shadows and artificial night lighting. A coarse-to-fine strategy utilizes the periodicity of the surface pattern distribution of the standard bicolor water gauge, which improves the reliability of water-line detection. The resolution and accuracy of water-level measurement are 1 mm and 1 cm, respectively. In particular, the MMD value is efficient at identifying extremely unfavorable conditions and reducing gross errors. MDPI 2019-09-24 /pmc/articles/PMC6806611/ /pubmed/31554301 http://dx.doi.org/10.3390/s19194141 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Zhang, Zhen
Zhou, Yang
Liu, Haiyun
Zhang, Lili
Wang, Huibin
Visual Measurement of Water Level under Complex Illumination Conditions
title Visual Measurement of Water Level under Complex Illumination Conditions
title_full Visual Measurement of Water Level under Complex Illumination Conditions
title_fullStr Visual Measurement of Water Level under Complex Illumination Conditions
title_full_unstemmed Visual Measurement of Water Level under Complex Illumination Conditions
title_short Visual Measurement of Water Level under Complex Illumination Conditions
title_sort visual measurement of water level under complex illumination conditions
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6806611/
https://www.ncbi.nlm.nih.gov/pubmed/31554301
http://dx.doi.org/10.3390/s19194141
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