• Accurate estimation of the illumination pattern’s orientation and wavelength in sinusoidal structured illumination microscopy 

      Lahrberg, Marcel; Singh, Mandeep; Khare, Kedar; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-01-05)
      Structured illumination microscopy is able to improve the spatial resolution of wide-field fluorescence imaging by applying sinusoidal stripe pattern illumination to the sample. The corresponding computational image reconstruction requires precise knowledge of the pattern’s parameters, which are its phase (φ) and wave vector (<b>p</b>). Here, a computationally inexpensive method for estimation of ...
    • Adaptive fluctuation imaging captures rapid subcellular dynamics 

      Opstad, Ida Sundvor; Ströhl, Florian; Birgisdottir, Åsa birna; Acuña Maldonado, Sebastian Andres; Kalstad, Trine; Myrmel, Truls; Agarwal, Krishna; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel, 2019-07-22)
      In this work we have explored the live-cell friendly nanoscopy method Multiple Signal Classification Algorithm (MUSICAL) for multi-colour imaging of various organelles and sub-cellular structures in the cardiomyoblast cell line H2c9. We have tested MUSICAL for fast (up to 230Hz), multi-colour time-lapse sequences of various sub-cellular structures (mitochondria, endoplasmic reticulum, microtubules, ...
    • Adaptive fluctuation imaging captures rapid subcellular dynamics 

      Opstad, Ida Sundvor; Ströhl, Florian; Birgisdottir, Åsa birna; Maldonado, Sebastián Andrés Acuña; Kalstad, Trine; Myrmel, Truls; Agarwal, Krishna; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-22)
      In this work we have explored the live-cell friendly nanoscopy method Multiple Signal Classification Algorithm (MUSICAL) for multi-colour imaging of various organelles and sub-cellular structures in the cardiomyoblast cell line H2c9. We have tested MUSICAL for fast (up to 230Hz), multi-colour time-lapse sequences of various sub-cellular structures (mitochondria, endoplasmic reticulum, microtubules, ...
    • Added value of multitemporal polarimetric UAVSAR data for permanent scatterers detection 

      Nikaein, Tina; Akbari, Vahid; Arefi, Hossein (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-05)
      In the last decades, differential synthetic aperture radar (SAR) interferometric (InSAR) (DInSAR) techniques have been used to estimate the Earth's surface deformation with high resolution. In this paper, we present an approach for increasing the quantity of permanent scattered pixels. These pixels are selected for DInSAR processing based on polarimetric information prepared by new sensors. The ...
    • Adhesive free PVDF copolymer focused transducers for high frequency acoustic imaging 

      Habib, Anowarul; Wagle, Sanat; Melandsø, Frank (Conference object; Konferansebidrag, 2019)
      The present study has demonstrated to produce a reliable PVDF copolymer focused transducers from a layer-by-layer deposition method by engraving milled spherical cavies in a PEI polymer substrate. The proposed method which process P(VDF-TrFE) from the fluid phase, is adhesive-free in the sense that it does not require any additional adhesive layers for material binding. The transducer was acoustically ...
    • ADNet++: A few-shot learning framework for multi-class medical image volume segmentation with uncertainty-guided feature refinement 

      Hansen, Stine; Gautam, Srishti; Salahuddin, Suaiba Amina; Kampffmeyer, Michael Christian; Jenssen, Robert (Journal article; Tidsskriftartikkel, 2023-08-02)
      A major barrier to applying deep segmentation models in the medical domain is their typical data-hungry nature, requiring experts to collect and label large amounts of data for training. As a reaction, prototypical few-shot segmentation (FSS) models have recently gained traction as data-efficient alternatives. Nevertheless, despite the recent progress of these models, they still have some essential ...
    • An Advanced Non-Gaussian Feature Space Method for POL-SAR Image Segmentation 

      Doulgeris, Anthony Paul; Eltoft, Torbjørn (Conference object; Konferansebidrag, 2013)
      This work extends upon our simple feature-based multichannel SAR segmentation method to incorporate highly desirable statistical properties into a computationally simple approach. The desirable properties include Markov random field contextual smoothing and goodness-of-fit testing to automatically obtain the significant number of classes. To achieve this we need to find an explicit class model to ...
    • Affinity-Guided Image-to-Image Translation for Unsupervised Heterogeneous Change Detection 

      Hansen, Mads Adrian (Master thesis; Mastergradsoppgave, 2019-12-16)
      Change detection in earth observation remote sensing images can be used to describe the extent of natural disasters, e.g., forest fires and floods. When time is of the essence, the ability to utilize heterogeneous images is fundamental, i.e., images that are not directly comparable due to the sensors used or the capturing conditions. The recent advances in machine learning have dispersed into the ...
    • Agreement and Complementarity of Sea Ice Drift Products 

      Johansson, Malin; Berg, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-01-08)
      Changes in Arctic sea ice have raised questions about changes in sea ice drift patterns. Reduced sea ice coverage may open up the Arctic to further exploration of maritime activities, particularly during the summer months. Given such changes, it is important to investigate differences between available sea ice drift products. Products based on synthetic aperture radar (SAR), radar scatterometer, and ...
    • Air temperature at 90 km altitude in the Artic obtained using meteor radar : validation, characterization and climate change. 

      Kluken, Lars Grytbakk (Master thesis; Mastergradsoppgave, 2011-09-30)
      Temperatures at 90 km altitude above Ramfjordmoen (69°N, 19°E) have been obtained with the Nippon/Norwegian Tromsø Meteor Radar. The temperatures have been derived from meteor radar decay rates using two techniques: the pressure based and the temperature gradient based methods. The results have been compared to the Microwave Limb Sounder (MLS) instrument on board the Aura spacecraft. It was found ...
    • Airborne Investigation of Quasi-Specular Ku-Band Radar Scattering for Satellite Altimetry Over Snow-Covered Arctic Sea Ice 

      de Rijke Thomas, Claude; Landy, Jack Christopher; Mallett, Robbie; Willatt, Rosemary; Tsamados, Michel; King, Joshua (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-22)
      Surface-based Ku-band radar altimetry investigations indicate that the radar signal is typically backscattered from well above the snow–sea ice interface. However, this would induce a bias in satellite altimeter sea ice thickness retrievals not reflected by buoy validation. Our study presents a mechanism to potentially explain this paradox: probabilistic quasi-specular radar scattering from the ...
    • The airglow layer emission altitude cannot be determined unambiguously from temperature comparison with lidars 

      Dunker, Tim (Journal article; Peer reviewed; Tidsskriftartikkel, 2018)
      I investigate the nightly mean emission height and width of the OH*(3–1) layer by comparing nightly mean temperatures measured by the ground-based spectrometer GRIPS 9 and the Na lidar at ALOMAR. The data set contains 42 coincident measurements taken between November 2010 and February 2014, when GRIPS 9 was in operation at the ALOMAR observatory (69.3° N, 16.0° E) in northern Norway. To closely ...
    • Aktive antenner for ultrabredbånd-radar til deteksjon av brystkreft 

      Ryeng, Kristoffer (Master thesis; Mastergradsoppgave, 2008-10-01)
      Motivasjonen for denne oppgaven er en aktiv, smertefri og ufarlig metode for deteksjon av brystkreft ved bruk av ultrabredbånd mikrobølgeradar. Montering av lavstøyforsterker direkte etter mottakerantennen har en positiv effekt på signal-til-støyforholdet i radar-systemet, og en vesentlig del av oppgaven er å måle lavstøyforsterkeren gir. Grunnleggende teori om mikrobølger, antenner, forsterkere, ...
    • Algal hot spots in a changing Arctic Ocean: Sea-ice ridges and the snow-ice interface 

      Fernández-Méndez, Mar; Olsen, Lasse Mork; Kauko, Hanna M.; Meyer, Amelie; Rösel, Anja; Merkouriadi, Ioanna; Mundy, Christopher John; Ehn, Jens K.; Johansson, Malin; Wagner, Penelope Mae; Ervik, Åse; Sorrell, BK; Duarte, Pedro; Wold, Anette; Hop, Haakon; Assmy, Phillipp (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-12)
      During the N-ICE2015 drift expedition north-west of Svalbard, we observed the establishment and development of algal communities in first-year ice (FYI) ridges and at the snow-ice interface. Despite some indications of being hot spots for biological activity, ridges are under-studied largely because they are complex structures that are difficult to sample. Snow infiltration communities can grow at ...
    • Alignment of Multifrequency SAR Images Acquired over Sea Ice Using Drift Compensation 

      Demchev, Denis; Eriksson, Leif E.B.; Hildeman, Anders; Dierking, Wolfgang Fritz Otto (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-07)
      In this article, we investigate the feasibility to align synthetic aperture radar (SAR) imagery based on a compensation for sea ice drift occurring between temporally shifted image acquisitions. The image alignment is a requirement for improving sea ice classification by combining multifrequency SAR images acquired at different times. Images obtained at different radar frequencies provide ...
    • An alternative approach for calculating the SAR damping ratio of verified oil slicks 

      Quigley, Cornelius Patrick; Johansson, Malin; Jones, Cathleen Elaine (Journal article; Tidsskriftartikkel; Peer reviewed, 2022)
      The damping ratio is a calculated feature that measures the contrast between oil-slicked water and the open ocean in SAR data. To implement the damping ratio, the current literature suggests estimating the open water backscatter by taking strips of undefined width across the range direction, obtaining the damping ratio as a function of incidence angle. We show in this paper that the method proposed ...
    • The altitude of green OI 557.7 nm and blue N2+ 427.8 nm aurora 

      Whiter, Daniel K.; Partamies, Noora; Gustavsson, Bjorn Johan; Kauristie, Kirsti (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-06)
      We have performed a large statistical study of the peak emission altitude of green O(1D2–1S0) (557.7 nm) and blue 1 N (427.8 nm) aurora using observations from a network of all-sky cameras stationed across northern Finland and Sweden recorded during seven winter seasons from 2000 to 2007. Both emissions were found to typically peak at about 114 km. The distribution of blue peak altitudes is more ...
    • Amplitude and size scaling for interchange motions of plasma filaments 

      Kube, Ralph; Wiesenberger, Matthias; Garcia, Odd Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-07)
      The interchange dynamics and velocity scaling of blob-like plasma filaments are investigated using a two-field reduced fluid model. For incompressible flows due to buoyancy, the maximum velocity is proportional to the square root of the relative amplitude and the square root of its cross-field size. For compressible flows in a non-uniform magnetic field, this square root scaling only holds ...
    • Analyse av energibruk og teknisk drift ved Bryne videregående skole 

      Tjøtta, Louise Mitchell (Master thesis; Mastergradsoppgave, 2019-12-15)
      Tidligere Bryne videregående skole (vgs.) og Time vgs. ble i 2015 slått sammen til nye Bryne vgs. I den anledning ble det bygget tre nye skolebygg med et moderne og komplekst energisystem. Skolen er et pilotprosjekt i tråd med Rogaland fylkeskommune sin miljøpolitikk og er bygget med fokus på bærekraftige prinsipper, lavt energiforbruk og bruk av energikilder med begrenset CO2 utslipp. Skolens varme ...
    • Analysis of Correlations between Energy Consumption, Structural Specifications and Climate-Induced Variables to increase Energy Efficiency in Households and Buildings through a Prediction Model 

      Rasmussen, Christoffer Stene (Master thesis; Mastergradsoppgave, 2021-05-31)
      In a world where the transition towards increasingly progressive renewable energy sources is of great importance moving towards sustainability for our planet and future generations, a large portion of mundane equipment and machinery will turn to the usage of electricity rather than fossil fuel as a resource. This does however pose some challenges to the infrastructure in place as it increases the ...