Remote sensing(RS)technologies are extensively exploited by scientists and a vast audience of local authorities,urban managers,and city planners.Coastal regions,geohazard-prone areas,and highly populated cities repres...Remote sensing(RS)technologies are extensively exploited by scientists and a vast audience of local authorities,urban managers,and city planners.Coastal regions,geohazard-prone areas,and highly populated cities represent natural laboratories to apply RS technologies and test new methods.Over the last decades,many efforts have been spent on improving Earth’s surface monitoring,including intensifying Earth Observation(EO)operations by the major national space agencies.They oversee to plan and make operational constellations of satellite sensors providing the scientific community with extensive research and development opportunities in the geoscience field.For instance,within this framework,the European Space Agency(ESA)and the Ministry of Science and Technology of China(MOST)have sponsored,since the early 2000s,the DRAGON initiative jointly carried out by the European and Chinese RS scientific communities.This manuscript aims to provide a synthetic overview of some research activities and new methods recently designed and applied and trace the route for further developments.The main findings are related to i)the analysis of flood risk in China,ii)the potential of new methods for the estimation and removal of ground displacement biases in small-baseline oriented interferometric Synthetic Aperture Radar(SAR)methods,iii)the analysis of the inundation risk in low-lying regions using coherent and incoherent SAR methods;and iv)the use of SAR-based technologies for marine applications.展开更多
Due to the spectral and spatial properties of pervious and impervious surfaces,image classification and information extraction in detailed,small-scale mapping of urban surface materials is quite difficult and complex....Due to the spectral and spatial properties of pervious and impervious surfaces,image classification and information extraction in detailed,small-scale mapping of urban surface materials is quite difficult and complex.Emerging methods and innovations in image classification have centred on object-based classification techniques and various segmentation techniques,which are fundamental to this approach.Consequently,the purpose of this study is to determine which classification method is most suitable for extracting linear features in terms of techniques and performance by comparing two classification methods,pixel-based approach and object-based approach,using WorldView-2 satellite imagery to specifically highlight linear features such as roads,building edges,and road dividers.Two applied algorithms,including support vector machines(SVM)and ruled-based,were evaluated using two distinct software.A comparison of the results reveals that the object-based classification has a higher overall resolution than the pixel-based classification.The output of rule-based classificationwas satisfactory,with an overall accuracy of 88.6%(ENVI)and 92.2%(e-Cognition).The SVM classification result contained misclassified impervious surfaces and other urban features,as well as mixed objects.This classification achieved an overall accuracy of 75.1%.Nonetheless,this study provides an excellent overview for understanding the differences in their performances on the same data,as well as a comparison of the software employed.展开更多
Detection of cracks in concrete structures is critical for their safety and the sustainability of maintenance processes.Traditional inspection techniques are costly,time-consuming,and inefficient regarding human resou...Detection of cracks in concrete structures is critical for their safety and the sustainability of maintenance processes.Traditional inspection techniques are costly,time-consuming,and inefficient regarding human resources.Deep learning architectures have become more widespread in recent years by accelerating these processes and increasing their efficiency.Deep learning models(DLMs)stand out as an effective solution in crack detection due to their features such as end-to-end learning capability,model adaptation,and automatic learning processes.However,providing an optimal balance between model performance and computational efficiency of DLMs is a vital research topic.In this article,three different methods are proposed for detecting cracks in concrete structures.In the first method,a Separable Convolutional with Attention and Multi-layer Enhanced Fusion Network(SCAMEFNet)deep neural network,which has a deep architecture and can provide a balance between the depth of DLMs and model parameters,has been developed.This model was designed using a convolutional neural network,multi-head attention,and various fusion techniques.The second method proposes a modified vision transformer(ViT)model.A two-stage ensemble learning model,deep featurebased two-stage ensemble model(DFTSEM),is proposed in the third method.In this method,deep features and machine learning methods are used.The proposed approaches are evaluated using the Concrete Cracks Image Data set,which the authors collected and contains concrete cracks on building surfaces.The results show that the SCAMEFNet model achieved an accuracy rate of 98.83%,the ViT model 97.33%,and the DFTSEM model 99.00%.These findings show that the proposed techniques successfully detect surface cracks and deformations and can provide practical solutions to realworld problems.In addition,the developed methods can contribute as a tool for BIM platforms in smart cities for building health.展开更多
基金supported by the DRAGON 5 ESA-MOST GREENISH project[grant number 58351].
文摘Remote sensing(RS)technologies are extensively exploited by scientists and a vast audience of local authorities,urban managers,and city planners.Coastal regions,geohazard-prone areas,and highly populated cities represent natural laboratories to apply RS technologies and test new methods.Over the last decades,many efforts have been spent on improving Earth’s surface monitoring,including intensifying Earth Observation(EO)operations by the major national space agencies.They oversee to plan and make operational constellations of satellite sensors providing the scientific community with extensive research and development opportunities in the geoscience field.For instance,within this framework,the European Space Agency(ESA)and the Ministry of Science and Technology of China(MOST)have sponsored,since the early 2000s,the DRAGON initiative jointly carried out by the European and Chinese RS scientific communities.This manuscript aims to provide a synthetic overview of some research activities and new methods recently designed and applied and trace the route for further developments.The main findings are related to i)the analysis of flood risk in China,ii)the potential of new methods for the estimation and removal of ground displacement biases in small-baseline oriented interferometric Synthetic Aperture Radar(SAR)methods,iii)the analysis of the inundation risk in low-lying regions using coherent and incoherent SAR methods;and iv)the use of SAR-based technologies for marine applications.
文摘Due to the spectral and spatial properties of pervious and impervious surfaces,image classification and information extraction in detailed,small-scale mapping of urban surface materials is quite difficult and complex.Emerging methods and innovations in image classification have centred on object-based classification techniques and various segmentation techniques,which are fundamental to this approach.Consequently,the purpose of this study is to determine which classification method is most suitable for extracting linear features in terms of techniques and performance by comparing two classification methods,pixel-based approach and object-based approach,using WorldView-2 satellite imagery to specifically highlight linear features such as roads,building edges,and road dividers.Two applied algorithms,including support vector machines(SVM)and ruled-based,were evaluated using two distinct software.A comparison of the results reveals that the object-based classification has a higher overall resolution than the pixel-based classification.The output of rule-based classificationwas satisfactory,with an overall accuracy of 88.6%(ENVI)and 92.2%(e-Cognition).The SVM classification result contained misclassified impervious surfaces and other urban features,as well as mixed objects.This classification achieved an overall accuracy of 75.1%.Nonetheless,this study provides an excellent overview for understanding the differences in their performances on the same data,as well as a comparison of the software employed.
文摘Detection of cracks in concrete structures is critical for their safety and the sustainability of maintenance processes.Traditional inspection techniques are costly,time-consuming,and inefficient regarding human resources.Deep learning architectures have become more widespread in recent years by accelerating these processes and increasing their efficiency.Deep learning models(DLMs)stand out as an effective solution in crack detection due to their features such as end-to-end learning capability,model adaptation,and automatic learning processes.However,providing an optimal balance between model performance and computational efficiency of DLMs is a vital research topic.In this article,three different methods are proposed for detecting cracks in concrete structures.In the first method,a Separable Convolutional with Attention and Multi-layer Enhanced Fusion Network(SCAMEFNet)deep neural network,which has a deep architecture and can provide a balance between the depth of DLMs and model parameters,has been developed.This model was designed using a convolutional neural network,multi-head attention,and various fusion techniques.The second method proposes a modified vision transformer(ViT)model.A two-stage ensemble learning model,deep featurebased two-stage ensemble model(DFTSEM),is proposed in the third method.In this method,deep features and machine learning methods are used.The proposed approaches are evaluated using the Concrete Cracks Image Data set,which the authors collected and contains concrete cracks on building surfaces.The results show that the SCAMEFNet model achieved an accuracy rate of 98.83%,the ViT model 97.33%,and the DFTSEM model 99.00%.These findings show that the proposed techniques successfully detect surface cracks and deformations and can provide practical solutions to realworld problems.In addition,the developed methods can contribute as a tool for BIM platforms in smart cities for building health.
