• AFSD: Adaptive Feature Space Distillation for Distributed Deep Learning 

      Khaleghian, Salman; Ullah, Habib; Johnsen, Einar Broch; Andersen, Anders; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-08)
      We propose a novel and adaptive feature space distillation method (AFSD) to reduce the communication overhead among distributed computers. The proposed method improves the Codistillation process by supporting longer update interval rates. AFSD performs knowledge distillates across the models infrequently and provides flexibility to the models in terms of exploring diverse variations in the training ...
    • Assessment of Polarimetric Variability by Distance Geometry for Enhanced Classification of Oil Slicks Using SAR 

      Marinoni, Andrea; Espeseth, Martine; Gamba, Paolo; Brekke, Camilla; Eltoft, Torbjørn (Peer reviewed; Chapter; Bokkapittel, 2019-11-14)
      In this paper, we introduce a new approach for investigation of polarimetric Synthetic Aperture Radar (PolSAR) images for oil slick analysis. Our method aims at enhancing discrimination of oil types by exploring the polarimetric features that can be produced by processing PolSAR scenes without dimensionality reduction. Taking advantage of a mixture description of the interactions among classes within ...
    • Automatic Selection of Relevant Attributes for Multi-Sensor Remote Sensing Analysis: A Case Study on Sea Ice Classification 

      Khachatrian, Eduard; Chlaily, Saloua; Eltoft, Torbjørn; Dierking, Wolfgang Fritz Otto; Dinessen, Frode; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-26)
      It is of considerable benefit to combine information obtained from different satellite sensors to achieve advanced and improved characterization of sea ice conditions. However, it is also true that not all the information is relevant. It may be redundant, corrupted, or unnecessary for the given task, hence decreasing the performance of the algorithms. Therefore, it is crucial to select an optimal ...
    • Capacity and Limits of Multimodal Remote Sensing: Theoretical Aspects and Automatic Information Theory-Based Image Selection 

      Chlaily, Saloua; Mura, Mauro Della; Chanussot, Jocelyn; Jutten, Christian; Gamba, Paolo; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-17)
      Although multimodal remote sensing data analysis can strongly improve the characterization of physical phenomena on Earth's surface, nonidealities and estimation imperfections between records and investigation models can limit its actual information extraction ability. In this article, we aim at predicting the maximum information extraction that can be reached when analyzing a given data set. By ...
    • Deep Semisupervised Teacher–Student Model Based on Label Propagation for Sea Ice Classification 

      Khaleghian, Salman; Ullah, Habib; Kræmer, Thomas; Eltoft, Torbjørn; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-14)
      In this article, we propose a novelteacher–student-based label propagation deep semisupervised learning (TSLP-SSL) method for sea ice classification based on Sentinel-1 synthetic aperture radar data. For sea ice classification, labeling the data precisely is very time consuming and requires expert knowledge. Our method efficiently learns sea ice characteristics from a limited number of labeled samples ...
    • ExtremeEarth meets satellite data from space 

      Hagos, Desta Haileselassie; Kakantousis, Theofilos; Vlassov, Vladimir; Sheikholeslami, Sina; Wang, Tianze; Dowling, Jim; Paris, Claudia; Marinelli, Daniele; Weikmann, Giulio; Bruzzone, Lorenzo; Khaleghian, Salman; Kræmer, Thomas; Eltoft, Torbjørn; Marinoni, Andrea; Pantazi, Despina-Athanasia; Stamoulis, George; Bilidas, Dimitris; Papadakis, George; Mandilaras, George; Koubarakis, Manolis; Troumpoukis, Antonis; Konstantopoulos, Stasinos; Muerth, Markus; Appel, Florian; Fleming, Andrew; Cziferszky, Andreas (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-26)
      Bringing together a number of cutting-edge technologies that range from storing extremely large volumes of data all the way to developing scalable machine learning and deep learning algorithms in a distributed manner and having them operate over the same infrastructure poses unprecedented challenges. One of these challenges is the integration of European Space Agency (ESA)’s Thematic Exploitation ...
    • 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 ...
    • An improved spatial and temporal reflectance unmixing model to synthesize time series of landsat-like images 

      Ma, Jianhang; Zhang, Wenjuan; Marinoni, Andrea; Gao, Lianru; Zhang, Bing (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-31)
      The trade-off between spatial and temporal resolution limits the acquisition of dense time series of Landsat images, and limits the ability to properly monitor land surface dynamics in time. Spatiotemporal image fusion methods provide a cost-efficient alternative to generate dense time series of Landsat-like images for applications that require both high spatial and temporal resolution images. The ...
    • An Improved Spatial and Temporal Reflectance Unmixing Model to Synthesize Time Series of Landsat-Like Images 

      Ma, Jianhang; Wenjuan, Zhang; Marinoni, Andrea; Lianru, Gao; Bing, Zhang (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-31)
      The trade-off between spatial and temporal resolution limits the acquisition of dense time series of Landsat images, and limits the ability to properly monitor land surface dynamics in time. Spatiotemporal image fusion methods provide a cost-efficient alternative to generate dense time series of Landsat-like images for applications that require both high spatial and temporal resolution images. The ...
    • A Multimodal Feature Selection Method for Remote Sensing Data Analysis Based on Double Graph Laplacian Diagonalization 

      Khachatrian, Eduard; Chlaily, Saloua; Eltoft, Torbjørn; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-13)
      When dealing with multivariate remotely sensed records collected by multiple sensors, an accurate selection of information at the data, feature, or decision level is instrumental in improving the scenes’ characterization. This will also enhance the system’s efficiency and provide more details on modeling the physical phenomena occurring on the Earth’s surface. In this article, we introduce a flexible ...
    • A Novel Rayleigh Dynamical Model for Remote Sensing Data Interpretation 

      Bayer, Fábio M.; Bayer, Débora M.; Marinoni, Andrea; Gamba, Paolo (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-19)
      This article introduces the Rayleigh autoregressive moving average (RARMA) model, which is useful to interpret multiple different sets of remotely sensed data, from wind measurements to multitemporal synthetic aperture radar (SAR) sequences. The RARMA model is indeed suitable for continuous, asymmetric, and nonnegative signals observed over time. It describes the mean of Rayleigh-distributed ...
    • On Importance of Off-Diagonal Elements in the Polarimetric Covariance Matrix: A Sea Ice Application Perspective 

      Ratha, Debanshu; Doulgeris, Anthony Paul; Marinoni, Andrea; Eltoft, Torbjørn (Conference object; Konferansebidrag, 2023-06)
    • On Measures of Uncertainty in Classification 

      Chlaily, Saloua; Ratha, Debanshu; Lozou, Pigi; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-12)
      Uncertainty is unavoidable in classification tasks and might originate from data (e.g., due to noise or wrong labeling), or the model (e.g., due to erroneous assumptions, etc). Providing an assessment of uncertainty associated with each outcome is of paramount importance in assessing the reliability of classification algorithms, especially on unseen data. In this work, we propose two measures of ...
    • On the Exploitation of Heterophily in Graph-Based Multimodal Remote Sensing Data Analysis 

      Taelman, Catherine Cecilia A; Chlaily, Saloua; Khachatrian, Eduard; Van Der Sommen, Fons; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2022)
      The field of Earth observation is dealing with increasingly large, multimodal data sets. An important processing step consists of providing these data sets with labels. However, standard label propagation algorithms cannot be applied to multimodal remote sensing data for two reasons. First, multimodal data is heterogeneous while classic label propagation algorithms assume a homogeneous network. ...
    • Performance Analysis of Roll-Invariant PolSAR Parameters from C-band images with Regard to Sea Ice Type Separation 

      Ratha, Debanshu; Johansson, Malin; Marinoni, Andrea; Eltoft, Torbjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06)
      The Polarimetric Synthetic Aperture Radar (PolSAR) backscatter from a target is dependent on the incidence angle. Consequently, the associated roll invariant parameters are affected by changes in incidence angle. In this work, we identify a few of these parameters that remain robust in identifying sea ice features even under large incidence angle variations. We conclude that the helicity angle ...
    • SAR and Passive Microwave Fusion Scheme: A Test Case on Sentinel-1/AMSR-2 for Sea Ice Classification 

      Khachatrian, Eduard; Dierking, Wolfgang; Chlaily, Saloua; Eltoft, Torbjørn; Dinessen, Frode; Hughes, Nick; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-14)
      The most common source of information about sea ice conditions is remote sensing data, especially images obtained from synthetic aperture radar (SAR) and passive microwave radiometers (PMR). Here we introduce an adaptive fusion scheme based on Graph Laplacians that allows us to retrieve the most relevant information from satellite images. In a first test case, we explore the potential of sea ice ...
    • Sea Ice Classification of SAR Imagery Based on Convolution Neural Networks 

      Khaleghian, Salman; Ullah, Habib; Kræmer, Thomas; Hughes, Nick; Eltoft, Torbjørn; Marinoni, Andrea (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-29)
      We explore new and existing convolutional neural network (CNN) architectures for sea ice classification using Sentinel-1 (S1) synthetic aperture radar (SAR) data by investigating two key challenges: binary sea ice versus open-water classification, and a multi-class sea ice type classification. The analysis of sea ice in SAR images is challenging because of the thermal noise effects and ambiguities ...
    • Selecting principal attributes in multimodal remote sensing for sea ice characterization 

      Khachatrian, Eduard; Chlaily, Saloua; Eltoft, Torbjørn; Marinoni, Andrea (Chapter; Bokkapittel, 2021)
      Automatic ice charting cannot be achieved using only SAR modalities. It is fundamental to combine information from other remote sensors with different characteristics for more reliable sea ice characterization. In this paper, we employ principal feature analysis (PFA) to select significant information from multimodal remote sensing data. PFA is a simple yet very effective approach that can be applied ...
    • Unsupervised Band Selection for Hyperspectral Datasets by Double Graph Laplacian Diagonalization 

      Khachatrian, Eduard; Chlaily, Saloua; Eltoft, Torbjørn; Gamba, Paolo; Marinoni, Andrea (Journal article; Tidsskriftartikkel, 2021)
      The vast amount of spectral information provided by hyperspectral images can be useful for different applications. However, the presence of redundant bands will negatively affect application performance. Therefore, it is crucial to select a relevant subset that preserves the information of the original set. In this paper, we present an automatic and accurate band selection method based on Graph ...