Rolf J. Korneliussen
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View article: Evening choruses in deep waters are associated with mesopelagic diel vertical migrations
Evening choruses in deep waters are associated with mesopelagic diel vertical migrations Open
Active and passive acoustic observation methods offer an effective approach to studying deep-sea fauna where direct monitoring is particularly challenging. Some of these mesopelagic organisms are part of Deep Scattering Layers (DSLs) which…
View article: Quantifying Area Back Scatter of Marine Organisms in the Arctic Ocean by Machine Learning-Based Post-Processing of Volume Back Scatter
Quantifying Area Back Scatter of Marine Organisms in the Arctic Ocean by Machine Learning-Based Post-Processing of Volume Back Scatter Open
As the sea ice reduces in both extent and thickness and the Arctic Ocean opens, there is substantial interest in mapping the marine ecosystem in this remote and until now largely inaccessible ocean. We used the R/V Kronprins Haakon during …
View article: Quantifying Area Back Scatter of Marine Organisms in the Arctic Ocean by Machine Learning Based Post-Processing of Volume Back Scatter
Quantifying Area Back Scatter of Marine Organisms in the Arctic Ocean by Machine Learning Based Post-Processing of Volume Back Scatter Open
As the sea ice reduces in both extent and thickness and the Arctic Ocean opens, there is substantial interest in mapping the marine ecosystem in this remote and until now largely inaccessible ocean. We have used R/V “Kronprins Haakon…
View article: Pulse duration, frequency band, and sweep direction effects on crosstalk in wideband backscattering measurements
Pulse duration, frequency band, and sweep direction effects on crosstalk in wideband backscattering measurements Open
Multiple broadband transducers are typically used to cover both a wide frequency range and fill in gaps resulting from sampling with multiple narrowband echosounders. Synchronized operation of these echosounders is preferred in many cases.…
View article: Combined algorithms for detection of acoustic categories
Combined algorithms for detection of acoustic categories Open
No abstracts are to be cited without prior reference to the author.There is a current desire to harvest marine resources by managing total marine ecosystems rather than single species of the ecosystems. By means of algorithms applied on hi…
View article: Verified acoustic identification of Atlantic mackerel
Verified acoustic identification of Atlantic mackerel Open
No abstracts are to be cited without prior reference to the author.Calibrated, digitised data from simultaneously working multi-frequency echo sounders with nearly identical and overlapping acoustic beams have been used to generate new, sy…
View article: On acoustic multi-frequency species identification and separation of Atlantic mackerel, Norwegian spring spawn herring and Norway pout
On acoustic multi-frequency species identification and separation of Atlantic mackerel, Norwegian spring spawn herring and Norway pout Open
No abstracts are to be cited without prior reference to the author.The accuracy of the multi-frequency species identification and separation algorithms may be significantly improved when the detailed acoustic scattering characteristics of …
View article: Acoustic backscatter from zooplankton and fish explored through an optimized model framework
Acoustic backscatter from zooplankton and fish explored through an optimized model framework Open
No abstracts are to be cited without prior reference to the author.The purpose of this work has been to test complementary methods in order to classify marine organisms, with particularly attention to zooplankton and fish. Algorithms to se…
View article: Recommendations for the collection of multifrequency acoustic data
Recommendations for the collection of multifrequency acoustic data Open
No abstracts are to be cited without prior reference to the author.Traditionally, collection of acoustic data has been optimised for a single frequency, while requirements for the optimal combination of multifrequency data has been given l…
View article: The relative frequency response, as derived from individually separated targets on cod, saithe and Norway pout
The relative frequency response, as derived from individually separated targets on cod, saithe and Norway pout Open
No abstracts are to be cited without prior reference to the author.The relative frequency response is an important acoustic feature used to characterise acoustic targets. This response has been defined as the sv, volume backscattering coef…
View article: Quantitative processing of broadband data as implemented in a scientific split‐beam echosounder
Quantitative processing of broadband data as implemented in a scientific split‐beam echosounder Open
The use of quantitative broadband echosounders for biological studies and surveys can offer considerable advantages over narrowband echosounders. These include improved spectral‐based target identification and significantly increased abili…
View article: Evaluation of echosounder data preparation strategies for modern machine learning models
Evaluation of echosounder data preparation strategies for modern machine learning models Open
Fish stock assessment and management requires accurate estimates of fish abundance, which are typically derived from echosounder observations using acoustic target classification (ATC). Skilled operators are regularly assisted in classifyi…
View article: Mesopelagic fish gas bladder elongation, as estimated from wideband acoustic backscattering measurements
Mesopelagic fish gas bladder elongation, as estimated from wideband acoustic backscattering measurements Open
Backscattered acoustic energy from a target varies with frequency and carries information about its material properties, size, shape, and orientation. Gas-bearing organisms are strong reflectors of acoustic energy at the commonly used freq…
View article: Finite-amplitude sound propagation effects in volume backscattering measurements for fish abundance estimation
Finite-amplitude sound propagation effects in volume backscattering measurements for fish abundance estimation Open
Scientific advice for governmental management of marine resources relies on acoustical observation methods. Quantification and identification of fish and plankton species are often achieved using multi-frequency acoustic data. Accurate mea…
View article: Finite amplitude sound propagation effects in volume backscattering measurements for fish abundance estimation
Finite amplitude sound propagation effects in volume backscattering measurements for fish abundance estimation Open
The upload contains measurement and simulation data for finite-amplitude sound propagation effects in volume backscattering measurements. The experimental data are from a trawl survey conducted in the North Sea with R/V "G. O. Sars", 6-7 N…
View article: Finite amplitude sound propagation effects in volume backscattering measurements for fish abundance estimation
Finite amplitude sound propagation effects in volume backscattering measurements for fish abundance estimation Open
Measurement data from a trawl survey conducted in the North Sea with R/V "G. O. Sars", passing several times over a group of Atlantic mackerel schools. The measurements are of the relative area backscattering coefficient (relative to 38 kH…
View article: Finite amplitude sound propagation effects in volume backscattering measurements for fish abundance estimation
Finite amplitude sound propagation effects in volume backscattering measurements for fish abundance estimation Open
The upload contains measurement and simulation data for finite-amplitude sound propagation effects in volume backscattering measurements. The experimental data are from a trawl survey conducted in the North Sea with R/V "G. O. Sars", 6-7 N…
View article: Finite amplitude sound propagation effects in volume backscattering measurements for fish abundance estimation
Finite amplitude sound propagation effects in volume backscattering measurements for fish abundance estimation Open
Measurement data from a trawl survey conducted in the North Sea with R/V "G. O. Sars", passing several times over a group of Atlantic mackerel schools. The measurements are of the relative area backscattering coefficient (relative to 38 kH…
View article: Quantitative processing of broadband data as implemented in a scientific splitbeam echosounder
Quantitative processing of broadband data as implemented in a scientific splitbeam echosounder Open
The use of quantitative broadband echosounders for biological studies and surveys offers considerable advantages over narrowband echosounders. These include improved spectral-based target identification and significantly increased ability …
View article: A deep scattering layer under the North Pole pack ice
A deep scattering layer under the North Pole pack ice Open
The 3.3 million km marine ecosystem around the North Pole, defined as the Central Arctic Ocean (CAO), is a blind spot on the map of the world's fish stocks. The CAO essentially comprises the permanently ice-covered deep basins and ridges o…
View article: Feasibility study on the use of scientific multibeam sonar to characterize the Atlantic Bluefin Tuna spawning stock
Feasibility study on the use of scientific multibeam sonar to characterize the Atlantic Bluefin Tuna spawning stock Open
The Institute of Marine Research (IMR) and the Polytechnic University of Valencia (UPV) were invited by ICCAT Atlantic-Wide Research Program for Bluefin Tuna (GBYP) to carry out a feasibility study on the use of scientific multibeam sonar,…
View article: Acoustic target classification.
Acoustic target classification. Open
Data are collected from a variety of acoustic systems in many countries to address a range of ecosystem monitoring and stock management objectives. A key step in the analysis of fisheries acoustics data is target classification, i.e. categ…
View article: Acoustic identification of marine species using a feature library
Acoustic identification of marine species using a feature library Open
Sonars and echosounders are widely used for remote sensing of life in the marine environment. There is an ongoing need to make the acoustic identification of marine species more correct and objective and thereby reduce the uncertainty of a…
View article: Power-Budget Equations and Calibration Factors for Fish Abundance Estimation Using Scientific Echo Sounder and Sonar Systems
Power-Budget Equations and Calibration Factors for Fish Abundance Estimation Using Scientific Echo Sounder and Sonar Systems Open
Acoustic methods used in fish abundance estimation constitute a key part of the analytic assessment that makes the basis for abundance estimation of marine resources. The methods rely on power-budget equations and calibrated systems. Diffe…