Viser treff 349-368 av 942

    • Hybrid graphene metasurface for near-infrared absorbers 

      Mahfuzur Rahman, MD; Raza, Aikifa; Younes, Hammad; Alghaferi, Amal; Chiesa, Matteo; Lu, Jin-You (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-19)
      We experimentally demonstrated an amorphous graphene-based metasurface yielding near-infrared super absorber characteristic. The structure is obtained by alternatively combining magnetron-sputtering deposition and graphene transfer coating fabrication techniques. The thickness constraint of the physical vapor–deposited amorphous metallic layer is unlocked and as a result, the as-fabricated graphene-based ...
    • Hydration dynamics and the future of small-amplitude afm imaging in air 

      Santos Hernandez, Sergio; Olukan, Tuza Adeyemi; Lai, Chia-Yun; Chiesa, Matteo (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-23)
      Here, we discuss the effects that the dynamics of the hydration layer and other variables, such as the tip radius, have on the availability of imaging regimes in dynamic AFM—including multifrequency AFM. Since small amplitudes are required for high-resolution imaging, we focus on these cases. It is possible to fully immerse a sharp tip under the hydration layer and image with amplitudes similar to ...
    • Hyperspectral image classification based on a shuffled group convolutional neural network with transfer learning 

      Liu, Yao; Gao, Lianru; Xiao, Chenchao; Qu, Ying; Zheng, Ke; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-01)
      Convolutional neural networks (CNNs) have been widely applied in hyperspectral imagery (HSI) classification. However, their classification performance might be limited by the scarcity of labeled data to be used for training and validation. In this paper, we propose a novel lightweight shuffled group convolutional neural network (abbreviated as SG-CNN) to achieve efficient training with a limited ...
    • Hyperspectral Nonlinear Unmixing by Using Plug-and-Play Prior for Abundance Maps 

      Wang, Zhicheng; Zhuang, Lina; Gao, Lianru; Marinoni, Andrea; Zhang, Bing; Ng, Michael K. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-16)
      Spectral unmixing (SU) aims at decomposing the mixed pixel into basic components, called endmembers with corresponding abundance fractions. Linear mixing model (LMM) and nonlinear mixing models (NLMMs) are two main classes to solve the SU. This paper proposes a new nonlinear unmixing method base on general bilinear model, which is one of the NLMMs. Since retrieving the endmembers’ abundances represents ...
    • IA-SSLM: Irregularity-Aware Semi-Supervised Deep Learning Model for Analyzing Unusual Events in Crowds 

      Aljaloud, Abdulaziz Salamah; Ullah, Habib (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-17)
      Analyzing unusual events is significantly important for video surveillance to ensure people safety. These events are characterized by irregular patterns that do not conform to the expected behavior in the surveillance scenes. We present a novel irregularity-aware semi-supervised deep learning model (IA-SSLM) for detection of unusual events. While most existing works depend on the availability ...
    • Ice extent in sub-arctic fjords and coastal areas from 2001 to 2019 analyzed from MODIS imagery 

      O'Sadnick, Megan Eileen; Petrich, Chris; Brekke, Camilla; Skardhamar, Jofrid (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-03)
      Results examining variations in the ice extent along the Norwegian coastline based on the analysis of Moderate Resolution Imaging Spectroradiometer (MODIS) images from 2001 to 2019, February through May, are presented. A total of 386 fjords and coastal areas were outlined and grouped into ten regions to assess seasonal and long-term trends in ice extent. In addition, three fjords were examined to ...
    • Ice extent in sub-arctic fjords and coastal areas from 2001 to 2019 analyzed from MODIS imagery 

      O'Sadnick, Megan; Petrich, Christian; Brekke, Camilla; Skarðhamar, Jofrid (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-03)
      Results examining variations in the ice extent along the Norwegian coastline based on the analysis of Moderate Resolution Imaging Spectroradiometer (MODIS) images from 2001 to 2019, February through May, are presented. A total of 386 fjords and coastal areas were outlined and grouped into ten regions to assess seasonal and long-term trends in ice extent. In addition, three fjords were examined to ...
    • Ice intelligence retrieval by remote sensing - Possibilities and challenges in an operational setting 

      Skarbø, Runa A.; Løset, Sveinung (Peer reviewed; Chapter; Bokkapittel, 2017)
      Detecting ice drift velocity when operating offshore in ice-covered waters is crucial during marine operations, as ice actions affect station keeping and ice management. Furthermore, other ice data/intelligence such as ice concentration and thickness are important parameters to determine ice resistance, evaluate performance of icebreakers and predict ice actions on structures. Different sensors are ...
    • ICEBEAR-3D: A Low Elevation Imaging Radar Using a Non-Uniform Coplanar Receiver Array for E Region Observations 

      Lozinsky, Adam; Hussey, Glenn; McWilliams, Kathryn; Huyghebaert, Devin Ray; Galeschuk, Draven (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-19)
      The Ionospheric Continuous-wave E region Bistatic Experimental Auroral Radar (ICEBEAR) has been reconfigured using a phase error minimization and stochastic antenna location perturbation technique. The resulting 45-baseline sparse non-uniform coplanar T-shaped array, ICEBEAR-3D, is used for aperture synthesis radar imaging of low elevation targets. The reconfigured receiver antenna array now has ...
    • ICEBEAR: An All‐Digital Bistatic Coded Continuous Wave Radar for Studies of the E Region of the Ionosphere 

      Huyghebaert, Devin; Hussey, Glenn; Vierinen, Juha; McWilliams, Kathryn; St‐Maurice, Jean-Pierre (Journal article; Peer reviewed, 2019-04-15)
      The Ionospheric Continuous-wave E region Bistatic Experimental Auroral Radar (ICEBEAR) is a coherent scatter ionospheric radar. It operates at a frequency of 49.5 MHz, which is ideal for observing E region coherent echoes. The radar is located in Saskatchewan, Canada, and is operated by the University of Saskatchewan. The ICEBEAR system uses a continuous-wave (CW) signal and requires isolation between ...
    • Iceberg detection in open water and sea ice using C-band radar polarimetry 

      Akbari, Vahid; Brekke, Camilla (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-04)
      Icebergs can cause a significant danger for shipping, offshore oil exploration, and undersea or subsea pipelines and production facilities. Synthetic aperture radar (SAR) is very valuable tool of detecting and monitoring icebergs in the often dark and cloud-covered polar regions. Detection of small icebergs floating in nonhomegeous sea clutter environments is a challenging task in remote sensing. ...
    • Image analysis and segmentation of polar mesospheric summer echoes 

      Jozwicki, Dorota (Conference object; Konferansebidrag, 2022-07)
    • Image denoising in acoustic microscopy using block-matching and 4D filter 

      Gupta, Shubham Kumar; Pal, Rishant; Ahmad, Azeem; Melandsø, Frank; Habib, Anowarul (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-14)
      Scanning acoustic microscopy (SAM) is a label-free imaging technique used in biomedical imaging, non-destructive testing, and material research to visualize surface and sub-surface structures. In ultrasonic imaging, noises in images can reduce contrast, edge and texture details, and resolution, negatively impacting post-processing algorithms. To reduce the noises in the scanned image, we have employed ...
    • Image inpainting in acoustic microscopy 

      Habib, Anowarul; Banerjee, Pragyan; Mishra, Sibasish; Yadav, Nitin; Agarwal, Krishna; Melandsø, Frank; Prasad, Dilip K (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-27)
      Scanning acoustic microscopy (SAM) is a non-ionizing and label-free imaging modality used to visualize the surface and internal structures of industrial objects and biological specimens. The image of the sample under investigation is created using high-frequency acoustic waves. The frequency of the excitation signals, the signal-to-noise ratio, and the pixel size all play a role in acoustic image ...
    • An imaging interferometry capability for the EISCAT Svalbard Radar. 

      Grydeland, Tom; Chau, J.L.; La Hoz, C.; Brekke, Asgeir (Journal article; Peer reviewed; Tidsskriftartikkel, 2005-01-31)
      Interferometric imaging (aperture synthesis imaging) is a technique used by radio astronomers to achieve angular resolution that far surpasses what is possible with a single large aperture. A similar technique has been used for radar imaging studies of equatorial ionospheric phenomena at the Jicamarca Radio Observatory. We present plans for adding an interferometric imaging capability to the ...
    • Imaging Sea Ice Structure by Remote Sensing Sensors 

      Eltoft, Torbjørn; Doulgeris, Anthony Paul; Brekke, Camilla; Solbø, Stian; Gerland, Sebastian; Hanssen, Alfred (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-06-14)
      This paper will investigate how new developments in remote sensing and sensor technologies can be applied to image the structure of the sea ice surface. Both segmentation of multipolarimetric synthetic aperture radar images and strategies for the analyses of polarimetric SAR data of sea ice are addressed. The analysis is based on a Radarsat 2 PolSAR scene of from the Fram Strait in September ...
    • Imaging the Effects of Whole-Body Vibration on the Progression of Hepatic Steatosis by Quantitative Ultrasound Based on Backscatter Envelope Statistics 

      Fang, Jui; Lai, Ming-Wei; Cheng, Hao-Tsai; Cristea, Anca; Zhou, Zhuhuang; Tsui, Po-Hsiang (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-29)
      Hepatic steatosis causes nonalcoholic fatty liver disease. Whole-body vibration (WBV) has been recommended to allow patients who have difficulty engaging in exercise to improve the grade of hepatic steatosis. This study proposed using ultrasound parametric imaging of the homodyned K (HK) distribution to evaluate the effectiveness of WBV treatments in alleviating hepatic steatosis. Sixty mice were ...
    • The Impact of Additive Noise on Polarimetric RADARSAT-2 Data Covering Oil Slicks 

      Espeseth, Martine; Skrunes, Stine; Brekke, Camilla; Johansson, Malin (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-14)
      We attempt to understand how a set of well known polari-metric Synthetic Aperture Radar (SAR) features are impacted by the additive system noise for mineral oil and produced water slicks. For this, we use quad-polarimetric SAR scenes from Radarsat-2. Oil slicks at sea can be detected using SAR instruments, and the dual- (HH-VV) and quad-polarimetric modes can provide additional information about the ...
    • Impact of assimilating sea ice concentration, sea ice thickness and snow depth in a coupled ocean-sea ice modelling system 

      Fritzner, Sindre Markus; Graversen, Rune; Christensen, Kai Håkon; Rostosky, Philip; Wang, Keguang (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-08)
      The accuracy of the initial state is very important for the quality of a forecast, and data assimilation is crucial for obtaining the best-possible initial state. For many years, sea-ice concentration was the only parameter used for assimilation into numerical sea-ice models. Sea-ice concentration can easily be observed by satellites, and satellite observations provide a full Arctic coverage. During ...
    • The impact of atmospheric Rossby waves and cyclones on the Arctic sea ice variability 

      Hofsteenge, Marte G.; Graversen, Rune Grand; Rydsaa, Johanne Hope; Rey, Zoé (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-17)
      The Arctic sea-ice extent has strongly declined over recent decades. A large inter-annual variability is superimposed on this negative trend. Previous studies have emphasised a significant warming effect associated with latent energy transport into the Arctic region, in particular due to an enhanced greenhouse effect associated with the convergence of the humidity transport over the Arctic. The ...