Journal Articles

Permanent URI for this collection

https://unbscholar.lib.unb.ca/handle/1882/12771

Articles. Typically the realization of research papers reporting original research findings published in a journal issue. (URI: http://purl.org/coar/resource_type/c_6501) Item types include:

  • editorial
  • journal article
    • corrigendum
    • data paper
    • research article
    • review article
    • software paper
  • letter to the editor

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Browsing Journal Articles by Subject "Geodesy and Geomatics Engineering"

Now showing 1 - 5 of 5
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    A Multi-Feature Fusion Using Deep Transfer Learning for Earthquake Building Damage Detection
    (Taylor and Francis, 2021) Abdi, Ghasem; Jabari, Shabnam
    With the recent tremendous improvements in the spatial, spectral, and temporal resolutions of remote sensing imaging systems, there has been a dramatic increase in the applications of remote sensing images. Amongst different applications of very high-resolution remote sensing images, damage detection for rapid emergency response is one of the most challenging ones. Recently, deep learning frameworks have enhanced the performance of earthquake damage detection by automatic extraction of strong deep features. However, most of the existing studies in this area focus on using nadir satellite images or orthophotos which limits the available data sources. This limitation decreases the temporal resolution of the practical images, which is a serious issue considering the emergency nature of damage detection applications. The objective of this study is to present a multimodal integrated structure to combine orthophoto and off-nadir images for earthquake building damage detection. In this context, a multi-feature fusion method based on deep transfer learning is presented, which contains four different steps, namely pre-processing, deep feature extraction, deep feature fusion, and transfer learning. To validate the presented framework, two comparative experiments are conducted on the 2010 Haiti earthquake using pre- and post-event off-nadir satellite images, which were collected by WorldView-2 (WV-2) satellite platform as well as a post-event airborne orthophoto. The results demonstrate considerable advantages in identifying damaged and non-damaged buildings with over 83% for the overall accuracy.
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    Delineation of Individual Tree Crowns Using High Spatial Resolution Multispectral WorldView-3 Satellite Imagery
    (Institute of Electrical and Electronics Engineers, 2021) Tong, Fei; Tong, Hengjian; Mishra, Rakesh; Zhang, Yun
    Delineation of individual tree crowns can provide valuable information for sustainable forest management and environmental protection. However, it is hard to find a reliable tree crown delineation method that can continually generate expected results in high spatial resolution multispectral satellite images, because most of the existing methods need user-assigned parameters that greatly affect the quality of the delineation results. In this article, we propose a method based on the marker-controlled watershed segmentation to delineate individual tree crowns using high spatial resolution multispectral WorldView-3 satellite imagery. A gradient binarization process is proposed to accurately locate tree crown borders. The threshold for the binarization is determined by a supervised searching process. Markers used in marker-controlled watershed segmentation are spatial local maxima detected from the information provided by tree crown borders. Moreover, the definition of spatial local maxima from the literature is improved to eliminate false treetops. To validate the performance of the proposed delineation method, delineation results are compared with those obtained from the spectral angle segmentation (SAS) method that has been proposed in literature because the quality of delineation results generated by SAS does not rely on user-assigned parameters. The experiment results in two test images demonstrate that the proposed method outperforms SAS in terms of both delineation accuracy and visual quality of the delineation map. Moreover, it is proved that the modified spatial local maxima are more reliable for detecting treetops.
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    Generating LoD2 City Models Using a Hybrid-Driven Approach: A Case Study for New Brunswick Urban Environment
    Krafczek, M.; Jabari, S.
    Today 55% of the world's population lives in urban areas, a proportion that is expected to increase to 68% by 2050 (UN, 2018). 3D city models can be used to prepare for the future city, enabling informed analysis and sustainable development. Based on the Open Geospatial Consortium (OGC) standard, i.e. cityGML, 3D city models can be produced in different levels of detail (LOD). CityGML-3 introduces five predefined LODs (LOD0-4), with LOD0 being a building footprint and LOD4 being a realistic model representing the exterior and interior of the buildings. Currently, LOD0 and LOD1 are available for most cities in developed countries while LOD2+ are superior for informed analysis in different applications such as disaster management and insurance. However, with the current status of knowledge and technology, the production, storage and maintenance of such models are very time-consuming and expensive. This paper presents an initial study for 3D city model generation with a focus on the urban structure of New Brunswick, Canada, which is an introductory part of a larger project for 3D city modelling and maintenance in Canada. This paper intended to explore existing off-the-shelf 3D city modelling products and check their accuracies. Furthermore, inspired by existing literature, we proposed a decision-tree-based methodology for LoD2 3D city model generation, which follows a combination of data-driven and model-driven approaches, i.e. a hybrid approach. We tested the quality of the final 3D models using different metrics such as overall accuracy, Kappa Coefficient, Root Mean Square Error (RMSE) and slope difference. Besides, we compared our results to two off-the-shelf products, namely Schematic Local Government City Engine LOD2 (SLGCE) modelling and OpenStreet Map City Engine (OSMCE) LOD2 modelling. The results showed that the proposed hybrid approach achieved higher accuracies using the mentioned metrics. This paper also discusses the pros and cons of the proposed method and offers insights for improving the results even further.
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    Hyperspectral remote sensing in lithological mapping, mineral exploration, and environmental geology: an updated review
    (Society of Photo-optical Instrumentation Engineers, 2021) Peyghambari, Sima; Zhang, Yun
    Hyperspectral imaging has been used in a variety of geological applications since its advent in the 1970s. In the last few decades, different techniques have been developed by geologists to analyze hyperspectral data in order to quantitatively extract geological information from the high-spectral-resolution remote sensing images. We attempt to review and update various steps of the techniques used in geological information extraction, such as lithological and mineralogical mapping, ore exploration, and environmental geology. The steps include atmospheric correction, dimensionality processing, endmember extraction, and image classification. It is identified that per-pixel and subpixel image classifiers can generate accurate alteration mineral maps. Producing geological maps of different surface materials including minerals and rocks is one of the most important geological applications. The hyperspectral images classification methods demonstrate the potential for being used as a main tool in the mining industry and environmental geology. To exemplify the potential, we also include a few case studies of different geological applications.
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    Multigranularity Multiclass-Layer Markov Random Field Model for Semantic Segmentation of Remote Sensing Images
    (IEEE, 2020) Zheng, Chen; Zhang, Yun; Wang, Leiguang
    Semantic segmentation is one of the most important tasks in remote sensing. However, as spatial resolution increases, distinguishing the homogeneity of each land class and the heterogeneity between different land classes are challenging. The Markov random field model (MRF) is a widely used method for semantic segmentation due to its effective spatial context description. To improve segmentation accuracy, some MRF-based methods extract more image information by constructing the probability graph with pixel or object granularity units, and some other methods interpret the image from different semantic perspectives by building multilayer semantic classes. However, these MRF-based methods fail to capture the relationship between different granularity features extracted from the image and hierarchical semantic classes that need to be interpreted. In this article, a new MRF-based method is proposed to incorporate the multigranularity information and the multilayer semantic classes together for semantic segmentation of remote sensing images. The proposed method develops a framework that builds a hybrid probability graph on both pixel and object granularities and defines a multiclass-layer label field with hierarchical semantic over the hybrid probability graph. A generative alternating granularity inference is suggested to provide the result by iteratively passing and updating information between different granularities and hierarchical semantics. The proposed method is tested on texture images, different remote sensing images obtained by the SPOT5, Gaofen-2, GeoEye, and aerial sensors, and Pavia University hyperspectral image. Experiments demonstrate that the proposed method shows a better segmentation performance than other state-of-the-art methods.