The Institut Cartogràfic de Catalunya (ICC) has developed an automatic advanced DInSAR processor (DISICC) for subsidence monitoring of large areas using data acquired by ERS-1/2, ENVISAT, and the future ALOS, TerraSAR-X and Radarsat 2... more
The Institut Cartogràfic de Catalunya (ICC) has developed an automatic advanced DInSAR processor (DISICC) for subsidence monitoring of large areas using data acquired by ERS-1/2, ENVISAT, and the future ALOS, TerraSAR-X and Radarsat 2 satellites. This processor performs the co-registration, interferogram generation, filtering, topographic cancellation, linear deformation model adjustment and non-linear displacement estimation, allowing the generation of classical and advanced DInSAR results combining information from different orbits and satellites. This new software is already operative and it is being used for a large project of continuous monitoring of subsidences in the whole territory of Catalonia (Spain).
Presents a new technique to remove phase noise from SAR interferograms. This new technique is based on the wavelet transform. The algorithm adapts to the quantity of noise, but does not process low coherence areas thereby avoiding the... more
Presents a new technique to remove phase noise from SAR interferograms. This new technique is based on the wavelet transform. The algorithm adapts to the quantity of noise, but does not process low coherence areas thereby avoiding the creation of artifacts or false information in these areas
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The successful launch of TerraSAR-X has made available high resolution Synthetic Aperture Radar images. In particular the following satellite characteristics and its benefits on ground deformation estimation application are evaluated... more
The successful launch of TerraSAR-X has made available high resolution Synthetic Aperture Radar images. In particular the following satellite characteristics and its benefits on ground deformation estimation application are evaluated within this work in comparison with four independent ENVISAT tracks: Wavelength: Compared to the C-band of Envisat and Radarsat, TerraSAR-X operates with a wavelength in the order of 3 cm. A change in the sub-pixel scattering mechanism is expected specially in pure and dense urban areas. Increased resolution: For ground motion movement this characteristic is of special interest for already built infrastructure monitoring. With more resolution (of about 3 meters per pixel contrasting with the ENVISAT 20 meters resolution) it is expected that the number of possibles points of measurement increases as well. Rapidity of acquisition: Another characteristic that is discussed is the rapid image acquisition (eleven days in comparison with the ENVISAT 35 days). ...
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The successful launch of TerraSAR-X has made high resolution Synthetic Aperture Radar images with a reduced temporal revisit time available. These new sensor characteristics influence the benefits of ground deformation estimation by means... more
The successful launch of TerraSAR-X has made high resolution Synthetic Aperture Radar images with a reduced temporal revisit time available. These new sensor characteristics influence the benefits of ground deformation estimation by means of advanced DInSAR techniques. This paper reviews the first experience in Persistent Scatterer Interferometry (PSI) processing, using a stack of TerraSAR-X Stripmap images. This processing was performed using the Stable Point Network (SPN) software. The selected test site is the city of Barcelona (Spain), showing different subsidence patterns due to underground works. Additionally, TerraSAR-X results show deformation profiles caused by thermal dilatation. The SPN software has been modified to detect and correct this type of signal, obtaining deformation profiles that are only related to ground movements. Finally, this paper presents a brief comparison of persistent scatterer density between ENVISAT and TerraSAR-X Stripmap data.
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... ( ) ( ) ( i n n i m m i n n i m m i n n i m m n n m m i i n n m m i i n n m m Tyxn Tyxn Tyx Tyx Tyx Tyx yx yx Tr Tb yxv yxvT Tyxyx ,, ,, , sin 4 , , 4 ,,,, − α α β β ε ε θ λ π λ π φ (1) ...
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... ( ) ( ) ( i i i i i i Tyxn Tyx yx sin Tr Tb yxvT Tyx ,, ,, , 4 , 4 ,, + + ⋅ ... ( ) ( ) ( N i i i Tyx Tyx j N yx 0 model ,, ,, exp 1 , φδ δφ γ (2) where N is the number of differential interferograms and δφmodel is the phase model... more
... ( ) ( ) ( i i i i i i Tyxn Tyx yx sin Tr Tb yxvT Tyx ,, ,, , 4 , 4 ,, + + ⋅ ... ( ) ( ) ( N i i i Tyx Tyx j N yx 0 model ,, ,, exp 1 , φδ δφ γ (2) where N is the number of differential interferograms and δφmodel is the phase model assumed as: ...
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Subsidence monitoring of areas affected by low velocity displacements is an extremely useful application of SAR (synthetic aperture radar) techniques. However, the required long time-baselines reduce the quality of the information stored... more
Subsidence monitoring of areas affected by low velocity displacements is an extremely useful application of SAR (synthetic aperture radar) techniques. However, the required long time-baselines reduce the quality of the information stored in differential interferograms, adding difficulties to their processing. Typical characteristics of these interferograms are the presence of coherent areas that correspond to urban zones and totally incoherent areas
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In this paper, advanced techniques for the generation of terrain deformation maps using SAR (Synthetic Aperture Radar) data are presented. One of the algorithms estimates the linear and non-linear components of the displacement, the error... more
In this paper, advanced techniques for the generation of terrain deformation maps using SAR (Synthetic Aperture Radar) data are presented. One of the algorithms estimates the linear and non-linear components of the displacement, the error of the Digital Elevation Model (DEM) used to cancel the topographic term from the interferograms, and the atmospheric artifacts. The input data is a set
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... in many papers: image registration, range filtering, interferogram generation, flat Earth correction, hge filtering and ... Interferometric coherence is degraded due to the high slopes of the terrain. ... F. Upez, J. Tena, 0.... more
... in many papers: image registration, range filtering, interferogram generation, flat Earth correction, hge filtering and ... Interferometric coherence is degraded due to the high slopes of the terrain. ... F. Upez, J. Tena, 0. Rodriguez, M. Bara, A. Broquetas, Precise geometry techniques ...
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This paper presents a closed formulation to evaluate the quality of terrain deformation maps obtained with multi-image differential interferometry. The analytical formulation, based on the application of the asymptotic covariance matrix,... more
This paper presents a closed formulation to evaluate the quality of terrain deformation maps obtained with multi-image differential interferometry. The analytical formulation, based on the application of the asymptotic covariance matrix, that propagates the interferogram coherences to the linear deformation and DEM error accuracies when using a stack of interferograms, is developed and validated with real data from the ERS
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This paper presents a new DIFSAR approach that allows us to detect and follow the temporal evolution of localized deformations. This approach, which is suitable for monitoring single buildings or structures, extends the capability of the... more
This paper presents a new DIFSAR approach that allows us to detect and follow the temporal evolution of localized deformations. This approach, which is suitable for monitoring single buildings or structures, extends the capability of the algorithm referred to as SBAS technique, originally developed for investigating large scale deformation phenomena. The proposed technique relies on small baseline interferograms only, in order to preserve the DIFSAR capability to provide spatially dense deformation maps; moreover, it requires two different sets of DIFSAR interferograms generated at low (multi-look data) and high (single-look data) spatial resolution, respectively. The algorithm has been tested with data acquired by the European remote sensing (ERS) satellite relative to the area of the city of Napoli (Italy) and the results have been validated by using geodetic data.
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This paper presents an advanced DInSAR-GIS technique developed by the Cartographic Institute of Catalonia (ICC) for the generation of precise terrain deformation maps using data acquired by satellite platforms. These radar systems, known... more
This paper presents an advanced DInSAR-GIS technique developed by the Cartographic Institute of Catalonia (ICC) for the generation of precise terrain deformation maps using data acquired by satellite platforms. These radar systems, known as Synthetic Aperture Radars (SAR), allow obtaining terrain reflectivity images, which are processed by means of DInSAR algorithms for monitoring ground stability. The great advantage of these techniques relies on the possibility of monitoring large areas with no need of field measurements and at low cost. This work presents several results obtained with the DISICC (Differential Interferometry SAR ICC) software developed at ICC and their integration into an ArcGIS environment for risk management.
As indicated in ICH M7 draft guidance, in silico predictive tools including statistically-based QSARs and expert analysis may be used as a computational assessment for bacterial mutagenicity for the qualification of impurities in... more
As indicated in ICH M7 draft guidance, in silico predictive tools including statistically-based QSARs and expert analysis may be used as a computational assessment for bacterial mutagenicity for the qualification of impurities in pharmaceuticals. To address this need, we developed and validated a QSAR model to predict Salmonella t. mutagenicity (Ames assay outcome) of pharmaceutical impurities using Prous Institute's Symmetry(SM), a new in silico solution for drug discovery and toxicity screening, and the Mold2 molecular descriptor package (FDA/NCTR). Data was sourced from public benchmark databases with known Ames assay mutagenicity outcomes for 7300 chemicals (57% mutagens). Of these data, 90% was used to train the model and the remaining 10% was set aside as a holdout set for validation. The model's applicability to drug impurities was tested using a FDA/CDER database of 951 structures, of which 94% were found within the model's applicability domain. The predictive performance of the model is acceptable for supporting regulatory decision-making with 84±1% sensitivity, 81±1% specificity, 83±1% concordance and 79±1% negative predictivity based on internal cross-validation, while the holdout dataset yielded 83% sensitivity, 77% specificity, 80% concordance and 78% negative predictivity. Given the importance of having confidence in negative predictions, an additional external validation of the model was also carried out, using marketed drugs known to be Ames-negative, and obtained 98% coverage and 81% specificity. Additionally, Ames mutagenicity data from FDA/CFSAN was used to create another data set of 1535 chemicals for external validation of the model, yielding 98% coverage, 73% sensitivity, 86% specificity, 81% concordance and 84% negative predictivity.
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In this paper, an advanced technique for the generation of deformation maps using synthetic aperture radar (SAR) data is presented. The algorithm estimates the linear and nonlinear components of the displacement, the error of the digital... more
In this paper, an advanced technique for the generation of deformation maps using synthetic aperture radar (SAR) data is presented. The algorithm estimates the linear and nonlinear components of the displacement, the error of the digital elevation model (DEM) used to cancel the topographic terms, and the atmospheric artifacts from a reduced set of low spatial resolution interferograms. The pixel
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The exploitation of satellite SAR interferometry has shown, in the last 20 years, a considerable improvement due to the development of new InSAR PSI techniques and to the launch of new satellite sensors with a better spatial and temporal... more
The exploitation of satellite SAR interferometry has shown, in the last 20 years, a considerable improvement due to the development of new InSAR PSI techniques and to the launch of new satellite sensors with a better spatial and temporal resolution. One of the most interesting applications is the possibility of mapping slow landslides processes. In this paper we present an analysis of the potential and limitations of InSAR techniques for mapping, studying and monitoring landslides. The analysis has been cast from recent research results conducted by IGME in the Rio Gállego upper basin in central Pyrenees (Spain). As a result of this analysis we present the main advantages and limitations of each of the sensors, bands and processing techniques.