The Experts below are selected from a list of 6246 Experts worldwide ranked by ideXlab platform
Michael Schluter - One of the best experts on this subject based on the ideXlab platform.
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quantification of the methane concentration field around pockmarks in lake constance with online membrane inlet mass spectrometry inspectr200 200
EPIC3EGU General Assembly Conference Abstracts Vienna Austria 2010-05-02-2010-05-07EGU General Assembly 2010 COPERNICUS, 2010Co-Authors: Torben Gentz, Michael SchluterAbstract:Worldwide, the release of methane from sediments of lakes, coastal regions as well as ocean margins is observed. The gas release is often associated with specific features like pockmarks (morphological depressions at the seafloor), mud volcanoes, cold seeps as well as occurrence of gas hydrates. For such sites gas plumes were observed by Underwater Camera systems as well as acoustic techniques. Compared to such semi-quantitative information, rather little-known is the concentration field of CH4 as well as other gases around e.g. pockmarks. This is mainly to the laborious sampling schemes (e.g. by Rosette Water Sampler) and rather time consuming CH4 analysis by gas chromatography. We investigated the CH4 concentration field around pockmarks in Lake Constance by application of membrane inlet mass spectrometry (Inspectr200-200) combined with a submersible pump system. By this means very steep horizontal and vertical gradients of methane concentrations were observed in bottom as well as surface waters. Compilation of the continuous gas analyses allowed a 3D visualisation of the CH4 concentration field above pockmarks and computation of methane inventories for the water column.
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online membrane inlet mass spectrometry inspectr200 200 for quantification of the methane concentration
EPIC3HEMS Workshop 2009 Santa Barbara California 2009-09-21-2009-09-24, 2009Co-Authors: Torben Gentz, Michael SchluterAbstract:Worldwide, the release of methane from sediments of lakes, coastal regions as well as ocean margins is observed. The gas release is often associated with specific features like pockmarks (morphological depressions at the seafloor), mud volcanoes, cold seeps as well as occurrence of gas hydrates. For such sites gas plumes were observed by Underwater Camera systems as well as acoustic techniques. Compared to such semi-quantitative information, rather little-known is the concentration field of CH4 as well as other gases around e.g. pockmarks. This is mainly to the laborious sampling schemes (e.g. by Rosette Water Sampler) and rather time consuming CH4 analysis by gas chromatography. We investigated the CH4 concentration field around pockmarks in Lake Constance by application of membrane inlet mass spectrometry (Inspectr200-200) combined with a submersible pump system. By this means very steep horizontal and vertical gradients of methane concentrations were observed in bottom as well as surface waters. Compilation of the continuous gas analyses allowed a 3D visualisation of the CH4 concentration field above pockmarks and computation of methane inventories for the water column.
Purser Autun - One of the best experts on this subject based on the ideXlab platform.
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Seafloor bathymetric maps derived from side scan data collected along OFOBS profiles during POLARSTERN cruise PS124 to the southern Weddell Sea
PANGAEA, 2021Co-Authors: Hehemann Laura, Purser Autun, Boehringer Lilian, Werner Ellen, Wenzhöfer FrankAbstract:The Ocean Floor Observation and Bathymetry System (OFOBS), used during Polarstern research cruise PS124 to the southern Weddell Sea , a towed Underwater Camera system equipped with both a high-resolution photo-Camera (iSiTEC, CANON EOS 5D Mark III) and a high-definition video-Camera (iSiTEC, Sony FCB-H11). The Cameras were mounted on a steel frame (150L x 92W x 105H cm), together with two strobe lights (iSiTEC UW-Blitz 250, TTL driven), three parallel laser pointers spaced with a distance of 50 cm used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOBS during deployments. Additionally mounted on the platform was an EdgeTech 2205 bathymetric side scan and BlueView M900-130 forward looking sonar systems, to become the Ocean Floor Observation and Bathymetry System (OFOBS). Auxiliary sensors include an iXBlue PHINS 6000, and an AML Micro-X 6000 SV-Xchange sound velocity probe. An iXBlue DVL system was installed to augment the output of the PHINS 6000. Within this data set, the bathymetric maps of the seafloor derived from the raw side scan data collected are provided at 10 and 20 cm resolutions
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OFOBS Seafloor images from the Svalbard Archipelago and Fram Strait, collected during RV MARIA S. MERIAN expedition MSM95 (GPF 19-2_05)
PANGAEA, 2021Co-Authors: Purser Autun, Hoge Ulrich, Hehemann Laura, Boehringer Lilian, Merten Veronique, Dreutter SimonAbstract:During the RV MARIA S. MERIAN cruise to the Svalbard Archipelago and the Fram Strait during September - October 2020 the Ocean Floor Observation and Bathymetry System (OFOBS) was used to collect still and video images, as well as sidescan data, from various locations surveyed during the research cruise. The OFOBS system consisted of a towed Underwater Camera system equipped with both a high-resolution photo-Camera (iSiTEC, CANON EOS 5D Mark III) and a high-definition video-Camera (iSiTEC, Sony FCB-H11) as well as an integrated sidescan sonar system. The Cameras were mounted on a steel frame (140L x 92W x 135H cm), together with two strobe lights (iSiTEC UW-Blitz 250, TTL driven), three laser pointers spaced with a distance of 50 cm used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOBS during deployments, with additional positioning information provided by the integrated INS and DVL systems. In automatic mode, a seabed photo, depicting an area of approximately 4 m², with variations depending on the actual height above ground, was taken every ~15 seconds to obtain series of "TIMER" stills distributed at regular distances along each of the survey profiles. Profile lengths varied in length depending on duration of the cast, usually determined by sea state conditions at time of survey. At a ship speed of 0.5 kn, the average distance between seabed images was approximately 5 m. Ship speed was however greatly influenced by ice conditions. Additional "HOTKEY" photos were taken from interesting objects (organisms, seabed features, etc) when they appeared in the live video feed
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Side scan sonar and swath bathymetry collected along OFOBS profiles during POLARSTERN cruise PS118
PANGAEA, 2021Co-Authors: Hehemann Laura, Purser Autun, Dreutter Simon, Dorschel Boris, Nordhausen AxelAbstract:The Ocean Floor Observation and Bathymetry System (OFOBS), used during Polarstern research cruise PS118 to the Wedell Sea and Powell Basin, was a towed Underwater Camera system equipped with both a high-resolution photo-Camera (iSiTEC, CANON EOS 5D Mark III) and a high-definition video-Camera (iSiTEC, Sony FCB-H11). The Cameras were mounted on a steel frame (150L x 92W x 105H cm), together with two strobe lights (iSiTEC UW-Blitz 250, TTL driven), three parallel laser pointers spaced with a distance of 50 cm used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOBS during deployments. For PS101 the OFOS was upgraded with a 85 cm tail to additionally mount an EdgeTech 2205 bathymetric side scan and BlueView M900-130 forward looking sonar systems, to become the Ocean Floor Observation and Bathymetry System (OFOBS). Auxiliary sensors include an iXBlue PHINS 6000, and an AML Micro-X 6000 SV-Xchange sound velocity probe. An iXBlue DVL system was installed to augment the output of the PHINS 6000, but was not stable during PS118. The side scan sonar operated on two frequencies (230 kHz & 540 kHz) and the bathymetric array receives the high frequency. During PS118 the OFOBS has been flying on an average altitude of 3m above the seabed. The resulting achievable sonar ranges were 100m (low frequency) and 50m (high frequency) to both sides of the vehicle. Bathymetry in *_binned files is binned with 800 equidistant data points of 10cm distance, 40m to both sides. Additional _stave files contain the raw stave data. Stave files can be replayed with EdgeTech Discover Bathymetric to bin the bathymetry with different settings
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Ocean Floor Observation and Bathymetry System (OFOBS) images of Neopagetopsis ionah ice fish nest arrays in the Filchner Trough, Antarctica collected during the PS124 Polarstern expedition
PANGAEA, 2021Co-Authors: Purser Autun, Hehemann Laura, Boehringer Lilian, Wenzhöfer FrankAbstract:During the RV POLARSTERN expedition PS124 to the Weddell Sea during Jan - April 2021 the Ocean Floor Observation and Bathymetry System (OFOBS) was used to collect still and video images, as well as sidescan data, from various locations surveyed during the research cruise. During the cruise the first extensive site of Neopagetopsis ionah nesting was discovered. This data set contains images from 4 OFOBS deployments, conducted at 1.5 and 3.5 m flight heights, and 0.5 and 1.5 knots. In the full data set, more than 12000 active fish nests are apparent. The OFOBS system consisted of a towed Underwater Camera system equipped with both a high-resolution photo-Camera (iSiTEC, CANON EOS 5D Mark III) and a high-definition video-Camera (iSiTEC, Sony FCB-H11) as well as an integrated sidescan sonar system. The Cameras were mounted on a steel frame (140L x 92W x 135H cm), together with two strobe lights (iSiTEC UW-Blitz 250, TTL driven), three laser pointers spaced with a distance of 50 cm used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOBS during deployments, with additional positioning information provided by the integrated INS and DVL systems. In automatic mode, a seabed photo, depicting an area of approximately 4-10 m**2, with variations depending on the actual height above ground, was taken every ~15 seconds to obtain series of TIMER stills distributed at regular distances along each of the survey profiles. Profile lengths varied in length depending on duration of the cast. At a ship speed of 0.5 kn, the average distance between seabed images was approximately 5 m, with this spacing being 15 m at 1.5 kt speed. Additional HOTKEY photos were taken from interesting objects (organisms, seabed features, etc) when they appeared in the live video feed
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Ocean Floor Observation and Bathymetry System (OFOBS) seafloor images of the Weddell Sea, Antarctica collected during the PS124 Polarstern expedition
PANGAEA, 2021Co-Authors: Purser Autun, Hehemann Laura, Boehringer Lilian, Werner Ellen, Wenzhöfer FrankAbstract:During the RV POLARSTERN expedition PS124 to the Weddell Sea during Jan - April 2021 the Ocean Floor Observation and Bathymetry System (OFOBS) was used to collect still and video images, as well as sidescan data, from various locations surveyed during the research cruise. In this data set ~11,700 seafloor Images from 16 deployments made across the Filchner Shelf, Filchner Sill and Weddell Sea seafloor are presented. The OFOBS system consisted of a towed Underwater Camera system equipped with both a high-resolution photo-Camera (iSiTEC, CANON EOS 5D Mark III) and a high-definition video-Camera (iSiTEC, Sony FCB-H11) as well as an integrated sidescan sonar system. The Cameras were mounted on a steel frame (140L x 92W x 135H cm), together with two strobe lights (iSiTEC UW-Blitz 250, TTL driven), three laser pointers spaced with a distance of 50 cm used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOBS during deployments, with additional positioning information provided by the integrated INS and DVL systems. In automatic mode, a seabed photo, depicting an area of approximately 4-10 m**2, with variations depending on the actual height above ground, was taken every ~15 seconds to obtain series of TIMER stills distributed at regular distances along each of the survey profiles. Profile lengths varied in length depending on duration of the cast. At a ship speed of 0.5 kn, the average distance between seabed images was approximately 5 m, with this spacing being 15 m at 1.5 kt speed. Additional HOTKEY photos were taken from interesting objects (organisms, seabed features, etc) when they appeared in the live video feed. One minute POSIDONIA position fixes were used in this current data set, so there is some offset of a few 10s of meters for some of the collected images
Stefano Cataudella - One of the best experts on this subject based on the ideXlab platform.
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a dual Camera system for counting and sizing northern bluefin tuna thunnus thynnus linnaeus 1758 stock during transfer to aquaculture cages with a semi automatic artificial neural network tool
Aquaculture, 2009Co-Authors: Corrado Costa, Michele Scardi, Valerio Vitalini, Stefano CataudellaAbstract:A dual Underwater Camera system connected, synchronized and powered via cable to a waterproof transportable computer, was developed. This device was used for acquiring tuna images during the transfer from fishing net to a floating cage, thus validating the potential advantages of the use of Underwater video monitoring. Two images per second were recorded during tuna transfer and stored for biometric analyses, which were carried out by means of a software tool based on Artificial Neural Networks (ANNs). The ANN was trained to convert distance between pixels in each pair of images into distance between points in the real objects, automatically correcting the estimates for distance from the Cameras and aspect. The ANN-based software tool allowed analysing tuna transfer images, providing biometric information of about 1000 tunas. The results were compared to conventional assessment methods.
Richard Towler - One of the best experts on this subject based on the ideXlab platform.
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Tracking Live Fish From Low-Contrast and Low-Frame-Rate Stereo Videos
IEEE Transactions on Circuits and Systems for Video Technology, 2015Co-Authors: Meng-che Chuang, Jenq-neng Hwang, Kresimir Williams, Richard TowlerAbstract:Nonextractive fish abundance estimation with the aid of visual analysis has drawn increasing attention. Unstable illumination, ubiquitous noise, and low-frame-rate (LFR) video capturing in the Underwater environment, however, make conventional tracking methods unreliable. In this paper, we present a multiple fish-tracking system for low-contrast and LFR stereo videos with the use of a trawl-based Underwater Camera system. An automatic fish segmentation algorithm overcomes the low-contrast issues by adopting a histogram backprojection approach on double local-thresholded images to ensure an accurate segmentation on the fish shape boundaries. Built upon a reliable feature-based object matching method, a multiple-target tracking algorithm via a modified Viterbi data association is proposed to overcome the poor motion continuity and frequent entrance/exit of fish targets under LFR scenarios. In addition, a computationally efficient block-matching approach performs successful stereo matching that enables an automatic fish-body tail compensation to greatly reduce segmentation error and allows for an accurate fish length measurement. Experimental results show that an effective and reliable tracking performance for multiple live fish with Underwater stereo Cameras is achieved.
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Multiple fish tracking via Viterbi data association for low-frame-rate Underwater Camera systems
2013 IEEE International Symposium on Circuits and Systems (ISCAS), 2013Co-Authors: Meng-che Chuang, Jenq-neng Hwang, Kresimir Williams, Richard TowlerAbstract:Non-extractive fish abundance estimation with the aid of visual analysis has drawn increasing attention. Low frame rate and variable illumination in the Underwater environment, however, makes conventional tracking methods unreliable. In this paper, a robust multiple fish tracking system for low-frame-rate Underwater stereo Cameras is proposed. With the result of fish segmentation, a computationally efficient block-matching method is applied to perform successful stereo matching. A multiple-feature matching cost function is utilized to give a simple but effective metric for finding the temporal match of each target. Built upon reliable stereo matching, a multiple-target tracking algorithm via the Viterbi data association is developed to overcome the poor motion continuity of targets. Experimental results show that an accurate Underwater live fish tracking result with stereo Cameras is achieved.
Wenzhöfer Frank - One of the best experts on this subject based on the ideXlab platform.
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Seafloor bathymetric maps derived from side scan data collected along OFOBS profiles during POLARSTERN cruise PS124 to the southern Weddell Sea
PANGAEA, 2021Co-Authors: Hehemann Laura, Purser Autun, Boehringer Lilian, Werner Ellen, Wenzhöfer FrankAbstract:The Ocean Floor Observation and Bathymetry System (OFOBS), used during Polarstern research cruise PS124 to the southern Weddell Sea , a towed Underwater Camera system equipped with both a high-resolution photo-Camera (iSiTEC, CANON EOS 5D Mark III) and a high-definition video-Camera (iSiTEC, Sony FCB-H11). The Cameras were mounted on a steel frame (150L x 92W x 105H cm), together with two strobe lights (iSiTEC UW-Blitz 250, TTL driven), three parallel laser pointers spaced with a distance of 50 cm used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOBS during deployments. Additionally mounted on the platform was an EdgeTech 2205 bathymetric side scan and BlueView M900-130 forward looking sonar systems, to become the Ocean Floor Observation and Bathymetry System (OFOBS). Auxiliary sensors include an iXBlue PHINS 6000, and an AML Micro-X 6000 SV-Xchange sound velocity probe. An iXBlue DVL system was installed to augment the output of the PHINS 6000. Within this data set, the bathymetric maps of the seafloor derived from the raw side scan data collected are provided at 10 and 20 cm resolutions
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Ocean Floor Observation and Bathymetry System (OFOBS) images of Neopagetopsis ionah ice fish nest arrays in the Filchner Trough, Antarctica collected during the PS124 Polarstern expedition
PANGAEA, 2021Co-Authors: Purser Autun, Hehemann Laura, Boehringer Lilian, Wenzhöfer FrankAbstract:During the RV POLARSTERN expedition PS124 to the Weddell Sea during Jan - April 2021 the Ocean Floor Observation and Bathymetry System (OFOBS) was used to collect still and video images, as well as sidescan data, from various locations surveyed during the research cruise. During the cruise the first extensive site of Neopagetopsis ionah nesting was discovered. This data set contains images from 4 OFOBS deployments, conducted at 1.5 and 3.5 m flight heights, and 0.5 and 1.5 knots. In the full data set, more than 12000 active fish nests are apparent. The OFOBS system consisted of a towed Underwater Camera system equipped with both a high-resolution photo-Camera (iSiTEC, CANON EOS 5D Mark III) and a high-definition video-Camera (iSiTEC, Sony FCB-H11) as well as an integrated sidescan sonar system. The Cameras were mounted on a steel frame (140L x 92W x 135H cm), together with two strobe lights (iSiTEC UW-Blitz 250, TTL driven), three laser pointers spaced with a distance of 50 cm used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOBS during deployments, with additional positioning information provided by the integrated INS and DVL systems. In automatic mode, a seabed photo, depicting an area of approximately 4-10 m**2, with variations depending on the actual height above ground, was taken every ~15 seconds to obtain series of TIMER stills distributed at regular distances along each of the survey profiles. Profile lengths varied in length depending on duration of the cast. At a ship speed of 0.5 kn, the average distance between seabed images was approximately 5 m, with this spacing being 15 m at 1.5 kt speed. Additional HOTKEY photos were taken from interesting objects (organisms, seabed features, etc) when they appeared in the live video feed
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Ocean Floor Observation and Bathymetry System (OFOBS) seafloor images of the Weddell Sea, Antarctica collected during the PS124 Polarstern expedition
PANGAEA, 2021Co-Authors: Purser Autun, Hehemann Laura, Boehringer Lilian, Werner Ellen, Wenzhöfer FrankAbstract:During the RV POLARSTERN expedition PS124 to the Weddell Sea during Jan - April 2021 the Ocean Floor Observation and Bathymetry System (OFOBS) was used to collect still and video images, as well as sidescan data, from various locations surveyed during the research cruise. In this data set ~11,700 seafloor Images from 16 deployments made across the Filchner Shelf, Filchner Sill and Weddell Sea seafloor are presented. The OFOBS system consisted of a towed Underwater Camera system equipped with both a high-resolution photo-Camera (iSiTEC, CANON EOS 5D Mark III) and a high-definition video-Camera (iSiTEC, Sony FCB-H11) as well as an integrated sidescan sonar system. The Cameras were mounted on a steel frame (140L x 92W x 135H cm), together with two strobe lights (iSiTEC UW-Blitz 250, TTL driven), three laser pointers spaced with a distance of 50 cm used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOBS during deployments, with additional positioning information provided by the integrated INS and DVL systems. In automatic mode, a seabed photo, depicting an area of approximately 4-10 m**2, with variations depending on the actual height above ground, was taken every ~15 seconds to obtain series of TIMER stills distributed at regular distances along each of the survey profiles. Profile lengths varied in length depending on duration of the cast. At a ship speed of 0.5 kn, the average distance between seabed images was approximately 5 m, with this spacing being 15 m at 1.5 kt speed. Additional HOTKEY photos were taken from interesting objects (organisms, seabed features, etc) when they appeared in the live video feed. One minute POSIDONIA position fixes were used in this current data set, so there is some offset of a few 10s of meters for some of the collected images
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Iceberg A74: Seafloor circumnavigation images collected during COSMUS expedition PS124
PANGAEA, 2021Co-Authors: Purser Autun, Boehringer Lilian, Werner Ellen, Holtappels Moritz, Hellmer, Hartmut H, Wenzhöfer FrankAbstract:During the RV POLARSTERN expedition PS124 to the Weddell Sea during Jan - April 2021 the Ocean Floor Observation and Bathymetry System (OFOBS) was used to collect still and video images, as well as sidescan data, from various locations surveyed during the research cruise. During the expedition, the giant iceberg A74 calved off from the Antarctic mainland. In this data set we present images taken from within the water column and the seafloor during part of the iceberg circumnavigation conducted by FS POLARSTERN on the 14th of March, 2021. The OFOBS system consisted of a towed Underwater Camera system equipped with both a high-resolution photo-Camera (iSiTEC, CANON EOS 5D Mark III) and a high-definition video-Camera (iSiTEC, Sony FCB-H11) as well as an integrated sidescan sonar system. The Cameras were mounted on a steel frame (140L x 92W x 135H cm), together with two strobe lights (iSiTEC UW-Blitz 250, TTL driven), three laser pointers spaced with a distance of 50 cm used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOBS during deployments, with additional positioning information provided by the integrated INS and DVL systems. In automatic mode, a seabed photo, depicting an area of approximately 4-10 m**2, with variations depending on the actual height above ground, was taken every ~15 seconds to obtain series of TIMER stills distributed at regular distances along each of the survey profiles. Profile lengths varied in length depending on duration of the cast. At a ship speed of 0.5 kn, the average distance between seabed images was approximately 5 m, with this spacing being 15 m at 1.5 kt speed. Additional HOTKEY photos were taken from interesting objects (organisms, seabed features, etc) when they appeared in the live video feed. One minute POSIDONIA position fixes were used in this current data set, so there is some offset of a few 10s of meters for some of the collected images
