Blar i forfatter "Holt, Benjamin"

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    • Analysis of evolving oil spills in full-polarimetric and hybrid-polarity SAR 

      Espeseth, Martine Mostervik; Skrunes, Stine; Jones, Cathleen Elaine; Brekke, Camilla; Holt, Benjamin; Doulgeris, Anthony Paul (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-25)
      Oil spill detection using a time series of images acquired off Norway in June 2015 with the uninhabited aerial vehicle synthetic aperture radar is examined. The relative performance of a set of features derived from quad-polarization versus hybrid-polarity (HP) modes in detection of various types of slicks as they evolve on a high wind driven sea surface is evaluated. It is shown that the HP mode ...

    • Can Mineral Oil Slicks Be Distinguished From Newly Formed Sea Ice Using Synthetic Aperture Radar? 

      Johansson, Malin; Espeseth, Martine; Brekke, Camilla; Holt, Benjamin (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-18)
      In this feasibility study discriminating oil slicks and newly formed sea ice using SAR imagery is investigated, using imagery from the L-band high-resolution Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) airborne and the satellite C-band RADARSAT-2 (RS-2) systems. To determine the separability of these two varying but similar appearing low backscatter ocean surfaces, multi-polarization ...

    • Characterization and discrimination of evolving mineral and plant oil slicks based on L-band synthetic aperture radar (SAR) 

      Jones, Cathleen; Espeseth, Martine Mostervik; Holt, Benjamin; Brekke, Camilla; Skrunes, Stine (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-10-18)
      Evolution of the damping ratio for Bragg wavenumbers in the range 32-43 rad/m is evaluated for oil slicks of different composition released in the open ocean and allowed to develop naturally. The study uses quad-polarimetric L-band airborne synthetic aperture radar data acquired over three mineral oil emulsion releases of different, known oil-to-water ratio, and a near-coincident release of 2-ethylhexyl ...

    • Cross-Correlation Between Polarization Channels in SAR Imagery Over Oceanographic Features 

      Brekke, Camilla; Jones, Cathleen; Skrunes, Stine; Holt, Benjamin; Espeseth, Martine; Eltoft, Torbjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-11)
      This letter discusses cross-correlation features de- rived from near-coincident RADARSAT-2 quad-polarimetric and RISAT-1 hybrid-polarity (HP) measurements collected during the NOrwegian Radar oil Spill Experiment in 2015 (NORSE2015). We show that the imaginary part of the cross-correlation between RH and RV is an HP parallel to the real part of the cross-correlation between HH and VV earlier ...

    • Distinguishing Mineral Oil Slicks from Low Wind Areas using Rapid Repeat Synthetic Aperture Radar Imagery 

      Quigley, Cornelius Patrick; Johansson, Anna Malin Kristin; Jones, Cathleen Elaine; Holt, Benjamin (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-18)
      A method for differentiating marine oil slicks from radar-dark, low wind areas in open water using rapid repeat SAR imagery is reported. The study uses data acquired by the airborne UAVSAR L-band SAR instrument, imaging the Coal Oil Point seep field near Santa Barbara, California. Time-series of images from three different days are analyzed, all containing both verified oil slicks and low wind zones. ...

    • Effect of Wind Direction and Incidence Angle on Polarimetric SAR Observations of Slicked and Unslicked Sea Surfaces 

      Skrunes, Stine; Brekke, Camilla; Jones, Cathleen Elaine; Espeseth, Martine; Holt, Benjamin (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-12)
      The objective of this paper is to investigate the dependency of oil spill observations in polarimetric SAR data on imaging geometry, i.e., on incidence angle and look direction relative to the wind. The study is based on quad-polarization data acquired by the Uninhabited Aerial Vehicle Synthetic Aperture Radar over experimental oil slicks under relatively high winds of 10–12 m/s over an 8-hour period. ...

    • The impact of system noise in polarimetric SAR imagery on oil spill observations 

      Espeseth, Martine; Brekke, Camilla; Jones, Cathleen Elaine; Holt, Benjamin; Freeman, Anthony (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-16)
      The effects of both system additive and multiplicative noise on the X-, C-, and L-band synthetic aperture radar (SAR) data covering oil slicks are examined. Prior studies have attempted to characterize such oil slicks, primarily through analysis of polarimetric SAR data. In this article, we factor in system noise that is added to the backscattered signal, introducing artifacts that can easily be ...

    • Measurement of Oil Slick Transport and Evolution in the Gulf of Mexico using L-band Synthetic Aperture Radar 

      Jones, Cathleen; Espeseth, Martine; Holt, Benjamin; Brekke, Camilla (Journal article; Tidsskriftartikkel, 2018-06)
      The transport and evolution of a mineral oil slick originating at a seep in the Gulf of Mexico approximately 16 km offshore of the mouth of the Mississippi River is measured using a series of images acquired at 40 minute intervals with the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), an L-band, high resolution, high signal-to-noise instrument operated by the U.S. National Aeronautics ...

    • A Multisensor Comparison of Experimental Oil Spills in Polarimetric SAR for High Wind Conditions 

      Skrunes, Stine; Brekke, Camilla; Jones, Cathleen Elaine; Holt, Benjamin (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-06-23)
      In this paper, we present the experimental setup and data collection during the Norwegian Radar oil Spill Experiment 2015, followed by a comparison of a subset of the multisensory synthetic aperture radar (SAR) imagery collected during the experiment. Multipolarization SAR data acquired by Radarsat-2, TerraSAR-X, and the uninhabited aerial vehicle synthetic aperture radar (UAVSAR) less than 6 min ...

    • Oil spill characterization in the hybrid-polarity SAR domain using log-cumulants 

      Espeseth, Martine; Skrunes, Stine; Brekke, Camilla; Salberg, Arnt Børre; Jones, Cathleen; Holt, Benjamin (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-10-18)
      Log-cumulants have proven to be an interesting tool for evaluating the statistical properties of potential oil spills in polarimetric Synthetic Aperture Radar (SAR) data within the common horizontal (H) and vertical (V) polarization basis. The use of first, second, and third order sample log-cumulants has shown potential for evaluating the texture and the statistical distributions, as well as ...