5,428 research outputs found

    Avaliação da evolução do índice de vegetação de teledetecção usando de técnicas de processamento de imagens

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    Vegetation has a substantial role as an indicator of anthropic effects, specifically in cases where urban planning is required. This is especially the case in the management of coastal cities, where vegetation exerts several effects that heighten the quality of life (alleviation of unpleasant weather conditions, mitigation of erosion, aesthetics, among others). For this reason, there is an increased interest in the development of automated tools for studying the temporal and spatial evolution of the vegetation cover in wide urban areas, with an adequate spatial and temporal resolution. We present an automated image processing workflow for computing the variation of vegetation cover using any publicly available satellite imagery (ASTER, SPOT, LANDSAT, MODIS, among others) and a set of image processing algorithms specifically developed. The automatic processing methodology was developed to evaluate the spatial and temporal evolution of vegetation cover, including the Normalized Difference Vegetation Index (NDVI), the vegetation cover percentage and the vegetation variation. A prior urban area digitalization is required. The methodology was applied in Monte Hermoso city, Argentina. The vegetation cover per city block was computed and three transects over the city were outlined to evaluate the changes in NDVI values. This allows the computation of several information products, like NDVI profiles, vegetation variation assessment, and classification of city areas regarding vegetation. The information is available in GIS-readable formats, making it useful as support for urban planning decisions.A vegetação tem um papel importante como indicador de efeitos antrópicos, especificamente nos casos em que o planejamento urbano é necessário. Este é especialmente o caso na gestão de cidades costeiras, onde a vegetação exerce diversos efeitos que elevam a qualidade de vida (alívio de condições climáticas desagradáveis, mitigação da erosão, estética, entre outras). Por essa razão, há um interesse crescente no desenvolvimento de ferramentas automatizadas para o estudo da evolução temporal e espacial da cobertura vegetal em grandes áreas urbanas, com adequada resolução espacial e temporal. Apresentamos um fluxo de trabalho automatizado de processamento de imagens para calcular a variação da cobertura vegetal usando qualquer imagem de satélite publicamente disponível (ASTER, SPOT, LANDSAT, MODIS, entre outros) e um conjunto de algoritmos de processamento de imagem desenvolvidos especificamente. A metodologia de processamento automático foi desenvolvida para avaliar a evolução espacial e temporal da cobertura vegetal, incluindo o Índice de Vegetação da Diferença Normalizada (NDVI), o percentual de cobertura vegetal e a variação da vegetação. Uma digitalização prévia da área urbana foi necessária. A metodologia foi aplicada na cidade de Monte Hermoso, na Argentina. A cobertura vegetal por quarteirão foi computada e três transectos sobre a cidade foram delineados para avaliar as mudanças nos valores de NDVI. Isso permite o cálculo de vários produtos de informação, como perfis de NDVI, avaliação da variação da vegetação e classificação das áreas da cidade em relação à vegetação. A informação está disponível em formatos legíveis pelo GIS, tornando-a útil como suporte para decisões de planejamento urbano.Fil: Revollo Sarmiento, Natalia Veronica. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Revollo Sarmiento, Gisela Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Huamantinco Cisneros, María Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geografía y Turismo; ArgentinaFil: Delrieux, Claudio Augusto. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Piccolo, Maria Cintia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Geografía y Turismo; Argentin

    SC-Fuse: A Feature Fusion Approach for Unpaved Road Detection from Remotely Sensed Images

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    Road network extraction from remote sensing imagery is crucial for numerous applications, ranging from autonomous navigation to urban and rural planning. A particularly challenging aspect is the detection of unpaved roads, often underrepresented in research and data. These roads display variability in texture, width, shape, and surroundings, making their detection quite complex. This thesis addresses these challenges by creating a specialized dataset and introducing the SC-Fuse model. Our custom dataset comprises high resolution remote sensing imagery which primarily targets unpaved roads of the American Midwest. To capture the diverse seasonal variation and their impact, the dataset includes images from different times of the year, capturing various weather conditions and offering a comprehensive view of these changing conditions. To detect roads from our custom dataset we developed SC-Fuse model, a novel deep learning architecture designed to extract unpaved road networks from satellite imagery. This model leverages the strengths of dual feature extractors: the Swin Transformer and a Residual CNN. By combining features from these, SC-fuse captures the local as well as the global context of the images. The fusion of these features is done by a Feature Fusion Module which uses Linear Attention Mechanism, to optimize the computational efficiency. A LinkNet based decoder is used to ensure precise road network reconstruction. The evaluation of SC-Fuse model is done using various metrics, including qualitative visual assessments, to test its effectiveness in unpaved road detection. Advisors: Ashok Samal and Cody Stoll

    Topology, homogeneity and scale factors for object detection: application of eCognition software for urban mapping using multispectral satellite image

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    The research scope of this paper is to apply spatial object based image analysis (OBIA) method for processing panchromatic multispectral image covering study area of Brussels for urban mapping. The aim is to map different land cover types and more specifically, built-up areas from the very high resolution (VHR) satellite image using OBIA approach. A case study covers urban landscapes in the eastern areas of the city of Brussels, Belgium. Technically, this research was performed in eCognition raster processing software demonstrating excellent results of image segmentation and classification. The tools embedded in eCognition enabled to perform image segmentation and objects classification processes in a semi-automated regime, which is useful for the city planning, spatial analysis and urban growth analysis. The combination of the OBIA method together with technical tools of the eCognition demonstrated applicability of this method for urban mapping in densely populated areas, e.g. in megapolis and capital cities. The methodology included multiresolution segmentation and classification of the created objects.Comment: 6 pages, 12 figures, INSO2015, Ed. by A. Girgvliani et al. Akaki Tsereteli State University, Kutaisi (Imereti), Georgi

    Airborne photogrammetry and LIDAR for DSM extraction and 3D change detection over an urban area : a comparative study

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    A digital surface model (DSM) extracted from stereoscopic aerial images, acquired in March 2000, is compared with a DSM derived from airborne light detection and ranging (lidar) data collected in July 2009. Three densely built-up study areas in the city centre of Ghent, Belgium, are selected, each covering approximately 0.4 km(2). The surface models, generated from the two different 3D acquisition methods, are compared qualitatively and quantitatively as to what extent they are suitable in modelling an urban environment, in particular for the 3D reconstruction of buildings. Then the data sets, which are acquired at two different epochs t(1) and t(2), are investigated as to what extent 3D (building) changes can be detected and modelled over the time interval. A difference model, generated by pixel-wise subtracting of both DSMs, indicates changes in elevation. Filters are proposed to differentiate 'real' building changes from false alarms provoked by model noise, outliers, vegetation, etc. A final 3D building change model maps all destructed and newly constructed buildings within the time interval t(2) - t(1). Based on the change model, the surface and volume of the building changes can be quantified

    Multitemporal Imagery Based Analysis of Urban Land in St. Tammany Parish in Conjunction with Socioeconomic Data

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    The role of urbanization in the history of civilization is a profound and intricate part of human geography. By utilizing socioeconomic data and then integrating it with more technological innovations, such as remote sensing, the spread of sprawl and the urban corridor can better be mapped and quantified by researchers. Many different types of socioeconomic data were implemented in addition to the remotely sensed data. In this paper, six Landsat 5 TM images were used to create land cover classification maps of the developed or built-up land in St. Tammany Parish from 1984 to 2008. It was found that, in addition to St. Tammany expanding in population, the urban areas are becoming denser using a method called the remote method. This method is an advanced function of density that allows researchers to estimate consumption of the developed land

    Multitemporal Imagery Based Analysis of Urban Land in St. Tammany Parish in Conjunction with Socioeconomic Data

    Get PDF
    The role of urbanization in the history of civilization is a profound and intricate part of human geography. By utilizing socioeconomic data and then integrating it with more technological innovations, such as remote sensing, the spread of sprawl and the urban corridor can better be mapped and quantified by researchers. Many different types of socioeconomic data were implemented in addition to the remotely sensed data. In this paper, six Landsat 5 TM images were used to create land cover classification maps of the developed or built-up land in St. Tammany Parish from 1984 to 2008. It was found that, in addition to St. Tammany expanding in population, the urban areas are becoming denser using a method called the remote method. This method is an advanced function of density that allows researchers to estimate consumption of the developed land

    Lineament mapping for groundwater exploration using remotely sensed imagery in a karst terrain : Rio Tanama and Rio de Arecibo basins in the northern karst of Puerto Rico

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    Remote sensing and advanced digital image processing techniques were developed and tested for delineating karst features important for the subterranean hydrology in the Tanamá River and Rio Grande de Arecibo catchments located in the North Coast Tertiary Basin of Puerto Rico, where groundwater contributes to base flow for surface water bodies which in itself is the main supply of drinking water. This aquifer region is a karst platform of carbonate rocks and clastic beds, thought to comprise a confined aquifer beneath and an unconfined aquifer. Products derived from ASTER, Landsat (ETM+ and TM), a NED DEM (30 m), and a LiDAR DEM (2 m) were analyzed in the interpretations of the karst flow system. In addition, field verification, VLF-EM, and previously published hydrologic data were analyzed to characterize fracturing and dissolution features on groundwater hydrology in the region. Remote sensing assessments show that Landsat PCA (incorporating thermal band,) ASTER PCA, LiDAR Hillshade were best at detecting “true” lineaments in this type of terrain. NDMI proved to be helpful in detecting moisture changes attributed to lineaments influencing the shallow hydrology in the karst. Geomorphic data agrees with lineaments as faulting and fracturing in addition to linear bedding control features. Sinkholes, springs and geotectonic evidence locations occur along and at the end of lineaments. Lineaments interpreted from LiDAR DEM data (Aspect, Hillshade) show regional geomorphotectonic evidence correlated to sharp river bends, hill alignment, and aspect trends

    Object Localization, Segmentation, and Classification in 3D Images

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    We address the problem of identifying objects of interest in 3D images as a set of related tasks involving localization of objects within a scene, segmentation of observed object instances from other scene elements, classifying detected objects into semantic categories, and estimating the 3D pose of detected objects within the scene. The increasing availability of 3D sensors motivates us to leverage large amounts of 3D data to train machine learning models to address these tasks in 3D images. Leveraging recent advances in deep learning has allowed us to develop models capable of addressing these tasks and optimizing these tasks jointly to reduce potential errors propagated when solving these tasks independently
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