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    Johannes Sveinsson

    Multisource classification methods based on neural networks, statistical modeling, genetic algorithms, and fuzzy methods are considered. For most of these methods, the individual data sources are at first treated separately and classified... more
    Multisource classification methods based on neural networks, statistical modeling, genetic algorithms, and fuzzy methods are considered. For most of these methods, the individual data sources are at first treated separately and classified by either statistical or neural methods. Then, several decision fusion schemes are applied to combine information from the individual data sources. These schemes include weighted consensus theory where
    Hybrid classification methods based on consensus from several data sources are considered. Each data source is at first treated separately and modeled using statistical methods. Then weighting mechanisms are used to control the influence... more
    Hybrid classification methods based on consensus from several data sources are considered. Each data source is at first treated separately and modeled using statistical methods. Then weighting mechanisms are used to control the influence of each data source in the combined classification. The weights are optimized in order to improve the combined classification accuracies. Both linear and nonlinear optimization methods
    The combination of multisource remote sensing and geographic data is believed to offer improved accuracies in land cover classification. For such classification, the conventional parametric statistical classifiers, which have been applied... more
    The combination of multisource remote sensing and geographic data is believed to offer improved accuracies in land cover classification. For such classification, the conventional parametric statistical classifiers, which have been applied successfully in remote sensing for the last two decades, are not appropriate, since a convenient multivariate statistical model does not exist for the data. In this paper, several single
    Page 1. Support Vector Machines in Multisource Classification Gisli Hreinn Halldorsson, Jon Atli Benediktsson and Johannes R. Sveinsson Engineering Research Institute, University of Iceland, Hjardarhaga 2-6, 107 Reykjavik, Iceland e-mail:... more
    Page 1. Support Vector Machines in Multisource Classification Gisli Hreinn Halldorsson, Jon Atli Benediktsson and Johannes R. Sveinsson Engineering Research Institute, University of Iceland, Hjardarhaga 2-6, 107 Reykjavik, Iceland e-mail: {ghh, benedikt, sveinsso}@hi.is ...
    Three methods are investigated for speckle reduction and enhancement of synthetic aperture radar (SAR) images in the orthogonal wavelet domain. The first method is a nonlinear method based on soft thresholding the wavelet coefficients for... more
    Three methods are investigated for speckle reduction and enhancement of synthetic aperture radar (SAR) images in the orthogonal wavelet domain. The first method is a nonlinear method based on soft thresholding the wavelet coefficients for logarithmically transformed SAR image data (Guo et al. 1994). The second method uses an enhanced adaptive Lee filter (Lopes et al., 1990) of the wavelet
    Parallel consensual neural networks (PCNN) are investigated. The PCNN architecture is based on statistical consensus theory and involves using stage neural networks with transformed input data. The input data are transformed several times... more
    Parallel consensual neural networks (PCNN) are investigated. The PCNN architecture is based on statistical consensus theory and involves using stage neural networks with transformed input data. The input data are transformed several times and the different transformed data are used as if they were independent inputs. The independent inputs are first classified using the stage neural networks. The output responses
    Page 1. Source Based Feature Extraction for Support Vector Machines in Hyperspectral Classification Gisli H. Halldorsson, Jon Atli Benediktsson and Johannes R. Sveinsson Department of Electrical and Computer Engineering ...
    Abstract—Two random forest (RF) approaches are explored; the RF-BHC (Binary Hierarchical Classifier) and the RF-CART (Classification and Regression Tree). Both methods are based on a collection (forest) of tree-like classifier systems... more
    Abstract—Two random forest (RF) approaches are explored; the RF-BHC (Binary Hierarchical Classifier) and the RF-CART (Classification and Regression Tree). Both methods are based on a collection (forest) of tree-like classifier systems where the difference is in the way the ...
    15 Random Forest Classification of Remote Sensing Data Sveinn R. Joelsson, Jon A. Benediktsson, and Johannes R. Sveinsson CONTENTS 15.1 Introduction...................................... more
    15 Random Forest Classification of Remote Sensing Data Sveinn R. Joelsson, Jon A. Benediktsson, and Johannes R. Sveinsson CONTENTS 15.1 Introduction................................... .................................................................................. 327 15.2 The Random Forest Classifier........ ...
    The purpose of this paper is to develop a method for denoising images corrupted with additive white Gaussian noise (AWGN). The noise degrades quality of the images and makes interpretations, analysis and segmentation of images harder. The... more
    The purpose of this paper is to develop a method for denoising images corrupted with additive white Gaussian noise (AWGN). The noise degrades quality of the images and makes interpretations, analysis and segmentation of images harder. The discrete curvelet transform is a new image representation approach that codes image edges more efficiently than the wavelet transform. On the other hand,
    15 Random Forest Classification of Remote Sensing Data Sveinn R. Joelsson, Jon A. Benediktsson, and Johannes R. Sveinsson CONTENTS 15.1 Introduction...................................... more
    15 Random Forest Classification of Remote Sensing Data Sveinn R. Joelsson, Jon A. Benediktsson, and Johannes R. Sveinsson CONTENTS 15.1 Introduction................................... .................................................................................. 327 15.2 The Random Forest Classifier........ ...
    Morphologicalfeature extraction (MFE) has been success-fully used to increase classification accuracy and reduce the noise levelfor classification ofaerial images. In this paper we explore feature selection and extraction for MFE using... more
    Morphologicalfeature extraction (MFE) has been success-fully used to increase classification accuracy and reduce the noise levelfor classification ofaerial images. In this paper we explore feature selection and extraction for MFE using random forests (RFs) for classification and ...
    ABSTRACT An abstract is not available.
    A new artificial neural network (ANN) architecture for classification of event-related potential (ERP) waveforms is proposed. The new architecture is called the parallel principal component neural network (PPCNN). The use of PPCNN is... more
    A new artificial neural network (ANN) architecture for classification of event-related potential (ERP) waveforms is proposed. The new architecture is called the parallel principal component neural network (PPCNN). The use of PPCNN is discussed in terms of classification of ERP data obtained from chronic schizophrenic patients and from normal volunteers
    Classification of hyperspectral data with high spatial resolution is discussed. A method based on mathematical morphology for pre-processing of the hyperspectral data is investigated. In this approach, opening and closing morphological... more
    Classification of hyperspectral data with high spatial resolution is discussed. A method based on mathematical morphology for pre-processing of the hyperspectral data is investigated. In this approach, opening and closing morphological transforms are used in order to isolate bright (opening) and dark (closing) structures in images, where bright/dark means brighter/darker than the surrounding features in the images. Then, a morphological profile is constructed based on the repeated use of openings and closings with a differently sized structuring element. In order to apply the morphological approach to hyperspectral data, principal components are computed. Then, the principal components are used as base images for the morphological profiles. The use of extended morphological profiles, based on more than one principal component is proposed. In experiments, two data sets are classified. The proposed method performs well in terms of classification accuracies. It gives similar overall accuracies to statistical approaches.
    Classification of hyperspectral data with high spa- tial resolution from urban areas is discussed. A previously pro- posed approach is based on using several principal components from the hyperspectral data to build morphological... more
    Classification of hyperspectral data with high spa- tial resolution from urban areas is discussed. A previously pro- posed approach is based on using several principal components from the hyperspectral data to build morphological profiles. These profiles are used all together in one extended morpho- logical profile, which is then classified by a neural network. A shortcoming of the approach is
    The use of random forests for classification of multisource data is investigated in this paper. Random Forest is a classifier that grows many classification trees. Each tree is trained on a bootstrapped sample of the training data, and at... more
    The use of random forests for classification of multisource data is investigated in this paper. Random Forest is a classifier that grows many classification trees. Each tree is trained on a bootstrapped sample of the training data, and at each node the algorithm only searches across a random subset of the variables to determine a split. To classify an input
    Several widely used methods have been proposed for fusing high resolution panchromatic data and lower resolution multi-channel data. However, many of these methods fail to maintain spectral consistency of the fused high resolution image,... more
    Several widely used methods have been proposed for fusing high resolution panchromatic data and lower resolution multi-channel data. However, many of these methods fail to maintain spectral consistency of the fused high resolution image, which is of high importance to many of the applications based on satellite data. Additionally, most conventional methods are loosely connected to the image forming physics
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