JosÉ Mura | Instituto Nacional de Pesquisas Espaciais (original) (raw)

Papers by JosÉ Mura

Research paper thumbnail of Paulo Gurgel

Revista GeoNorte, Mar 11, 2024

Research paper thumbnail of 3D forest structure analysis from optical and LIDAR data

In Austria about half of the entire area (46 %) is covered by forests. The majority of these fore... more In Austria about half of the entire area (46 %) is covered by forests. The majority of these forests are highly managed and controlled in growth. Besides timber production, forest ecosystems play a multifunctional role including climate control, habitat provision and, especially in Austria, protection of settlements. The interrelationships among climatic, ecological, social and economic dimensions of forests require technologies for monitoring both the state and the development of forests. This comprises forest structure, species and age composition and, forest integrity in general. Assessing forest structure for example enables forest managers and natural risk engineers to evaluate whether a forest can fulfil its protective function or not. Traditional methods for assessing forest structure like field inventories and aerial photo interpretation are intrinsically limited in providing spatially continuous information over a large area. The Centre for Geoinformatics (Z_GIS) in collaboration with the National Park Bayerischer Wald, Germany and the Stand Montafon, Austria, has tested and applied advanced approaches of integrating multispectral optical data and airborne laser scanning (ALS) data for (1) forest stand delineation, (2) single tree detection and (3) forest structure analysis. As optical data we used RGBI line scanner data and CIR air-photos. ALS data were raw point data (10 pulses per sqm) and normalised crown models (nCM) at 0.5 m and 1 m resolution. (1) Automated stand delineation was done by (a) translating a key for manual mapping of forest development phases into a rule-based system via object-relationship modelling (ORM); and (b) by performing multi-resolution

Research paper thumbnail of The significance of geological structures on the subsidence phenomenon at the Maceió salt dissolution field (Brazil)

Research paper thumbnail of Análise de Arquiteturas para Processamento de Imagens

Anais do I Simpósio Brasileiro de Arquitetura de Computadores e Processamento Paralelo (SBACC 1987)

Após uma breve introdução sobre as atividades de Processamento de Imagens no INPE, são mostradas ... more Após uma breve introdução sobre as atividades de Processamento de Imagens no INPE, são mostradas as características principais da familia de sistemas SITIM, seguindo-se uma apresentação dos tipos de procedimentos mais utilizados em Processamento de Imagens. São discutidas algumas opções jã testadas para aumento de desempenho do sistema, através do uso de placas aceleradoras, e ao final são apresentadas as perspectivas de desenvolvimento futuro, tanto na área de placas aceleradoras como sistemas baseados em arquitetura paralela, associados a unidades de armazenamento de imagens avançadas.

Research paper thumbnail of Análise De Deformação De Pilhas De Disposição De Estéril Na Província Mineral De Carajás Com Uso De Dados Stripmap Do Satélite Terrasar-X

Revista Brasileira de Cartografia, Apr 27, 2016

A produção mineral brasileira encontra-se entre as maiores do mundo, atuando como um dos pilares ... more A produção mineral brasileira encontra-se entre as maiores do mundo, atuando como um dos pilares da sustentação econômica. O processo minerador envolve, entre outras etapas, a retirada do material sólido sem valor comercial agregado ao minério, denominado estéril. Após sua separação do minério, os estéreis são transportados e dispostos em Pilhas de Disposição de Estéril (PDEs), que sofrem assentamentos durante e após esta operação. A possibilidade de ocorrência de acidentes nessas estruturas e seus impactos ambientais requerem ferramentas efi cientes para o planejamento e prevenção ou minimização de eventuais danos. Neste contexto o Sensoriamento Remoto, em especial o Radar de Abertura Sintética (SAR) e suas técnicas são ferramentas efi cientes para o monitoramento de deformações superfi ciais por permitir uma visão sinóptica de grandes áreas, imageamento periódico e pouca infl uência atmosférica. Assim, o objetivo deste trabalho consistiu em verifi car a aplicabilidade da técnica Interferometria Diferencial por Séries Temporais (DInSAR Time-Series) associada à Intensity Tracking para a detecção de deformações superfi ciais nos taludes das PDEs NWI, W e SIV da Província Mineral de Carajás utilizando imagens TerraSAR-X. As técnicas mostraram potencial na detecção e estimativa do comportamento superfi cial das PDEs. A DInSAR Time-Series apresentou medidas quantitativas com precisão centimétrica, e a Intensity Tracking forneceu resultados de inferência acerca do comportamento superfi cial, recobrindo também regiões com ausência de resultados DInSAR Time-Series, embora com menor precisão.

Research paper thumbnail of Ground displacements revealed by A-DInSAR analysis in the Germano iron mining complex before and after the Fundão Dam collapse using Sentinel-1 data

Journal of Applied Remote Sensing

Abstract. Advanced differential SAR interferometry (A-DInSAR) has been used as an effective monit... more Abstract. Advanced differential SAR interferometry (A-DInSAR) has been used as an effective monitoring tool in mining environments. This work presents an investigation of surface displacement in the Germano iron mining complex (Mariana, Minas Gerais, Brazil), where on November 5, 2015, the Fundão tailings dam collapsed. Initially, the analysis was performed with 14 Sentinel-1 images, acquired from May 8, 2015, to November 4, 2015, and focused on the Fundão dam before its rupture to detect prior signs of surface deformations. The analysis after the Fundão dam collapse was conducted in the Germano area using 43 Sentinel-1 images, acquired from November 16, 2015 to May 15, 2017, and aimed at detecting surface displacement on the remaining infrastructure, the Sela&Tulipa and Selinha dikes and the main Germano tailings dam, which were directly or indirectly affected by the accident. The results reveal precursor signals of surface displacement at the Fundão dam prior to rupture, particularly on the left abutment setback sector where the collapse started according to a witness, reaching accumulated values of up to −60 mm. The results provided by the A-DInSAR analysis after the dam collapse indicate a stability in the Sela&Tulipa and Selinha dikes as well as in the main Germano dam, which is corroborated by in situ topographic measurements. On the auxiliary dikes within the Germano reservoir, accumulated displacement of up to −90 mm caused by settlements and continuous traffic of vehicles was detected. In addition, the detected accumulate displacement within the reservoir showed values of up to −120 mm, in general caused by settlements of the waste dry material due to the inactivity of the mining process. The investigation emphasized the important role that satellite-based A-DInSAR can play in mitigating possible accidents and for operational planning and risk assessment in mining operations.

Research paper thumbnail of Monitoring Horizontal and Vertical Components of SAMARCO Mine Dikes Deformations by DInSAR-SBAS Using TerraSAR-X and Sentinel-1 Data

Mining

This article presents an investigation of ground movement measurements based on a combination of ... more This article presents an investigation of ground movement measurements based on a combination of TerraSAR-X and Sentinel-1 data, in opposite tracks, aiming to detect ground de-formation of the remaining dikes of Germano mine, after the Fundão dam collapse. The differential interferometry technique SBAS (Small Baseline Subset) was applied to obtain the deformation of the surface in different Line of Sight (LoS), in order to carry out the vector decomposition and generate the deformation measurements in the vertical and horizontal directions. A set of 37 single-look complex (SLC) images of TerraSAR-X (TSX), acquired during the period from 19 February 2016 to 15 May 2017, and 37 SLC images of Sentinel-1, acquired from 8 February 2016 to 15 May 2017, were used to perform this investigation. For the TerraSAR-X interferometric processing, a coherence threshold of 40%, 4 looks in range and 2 looks in azimuth, 1200 m of atmospheric filter, and 10 % of max normal baseline of the critical wer...

Research paper thumbnail of Registro Automático De Imagens Sar Interferométricas

Revista Brasileira de Cartografia, Sep 20, 2012

O presente artigo apresenta uma metodologia para registro automático de imagens SAR interferométr... more O presente artigo apresenta uma metodologia para registro automático de imagens SAR interferométricas. Primeiramente as imagens SAR, no formato complexo, são registradas grosseiramente utilizando técnicas de correlação, que resultam em deslocamentos em alcance e azimute, na escala de pixel, aplicados à segunda imagem, sem necessidade de interpolação. Opcionalmente pode ser aplicada a filtragem espectral em azimute nas imagens corregistradas, para a melhoria da coerência interferométrica entre elas. A segunda etapa do registro consiste na aplicação do registro fino, através de uma grade de pequenas janelas distribuídas de forma regular sobre cada uma das imagens onde, para cada janela, é calculado o deslocamento fracionário (da ordem de subpixel) por correlação, resultando em uma grade de deslocamentos, de onde são calculados os polinômios de deformação nos sentidos de alcance e azimute, para a reamostragem da segunda imagem. A partir das imagens corregistradas pode-se aplicar, opcionalmente, a filtragem espectral no sentido de alcance, para a melhoria da coerência interferométrica entre elas. A qualidade do registro final foi avaliada através da análise da imagem de coerência e pelo método dos resíduos aplicados na fase interferométrica gerada a partir das imagens corregistradas. Os algoritmos foram implementados em IDL/ENVI e testados em um par de imagens do SIR-C e um par do ALOS/PALSAR.

Research paper thumbnail of www.mdpi.com/journal/remotesensing Article A Phase-Offset Estimation Method for InSAR DEM Generation Based on Phase-Offset Functions

Abstract. This paper presents a novel method for estimating the absolute phase offset in interfer... more Abstract. This paper presents a novel method for estimating the absolute phase offset in interferometric synthetic aperture radar (SAR) measurements for digital elevation model (DEM) generation. The method is based on “phase-offset functions (POF), ” relating phase offset to topographic height, and are computed for two different overlapping interferometric data acquisitions performed with considerably different incidence angles over the same area of interest. For the purpose of extended mapping, opposite viewing directions are preferred. The two “phase-offset functions ” are then linearly combined, yielding a “combined phase-offset function (CPOF)”. The intersection point of several straight lines (CPOFs), corresponding to different points in the overlap area allows for solving the phase offset for both acquisitions. Aiming at increasing performance and stability, this intersection point is found by means of averaging many points and applying principal component analysis. The method...

Research paper thumbnail of Detecting Clearcut Deforestation Employing Deep Learning Methods and SAR Time Series

2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, 2021

Automating the systematic monitoring of deforestation in the Brazilian biomes has become imperati... more Automating the systematic monitoring of deforestation in the Brazilian biomes has become imperative. In this sense, a promising research field lies upon the exploitation of orbital imaging based on Synthetic Aperture Radar (SAR) sensors, since this technology is less affected by cloud cover, allowing systematic data acquisitions. In addition, the growing availability of with no charge SAR data products enables investigations on the use of time series extracted from this category of instruments, paving the way for more sophisticated temporal analyzes. This work presents the results of a SAR time series classification model designed to identify clearcut deforestation patterns in time, through an Artificial Intelligence approach known as Recurrent Neural Networks. The classification was performed using 5216 samples of Sentinel-1 time series within the Amazon basin, reaching an overall accuracy of 96.74%.

Research paper thumbnail of Advanced DINSAR analysis on dam stability monitoring: A case study in the Germano mining complex (Mariana, Brazil) with SBAS and PSI techniques

Remote Sensing Applications: Society and Environment, 2019

This work presents an investigation of detection and monitoring of surface motions using Advanced... more This work presents an investigation of detection and monitoring of surface motions using Advanced Differential SAR Interferometry (A-DInSAR) with SBAS (Small Baseline Subset) and PSI (Persistent Scatterer Interferometry) techniques in the Germano iron mining complex region (Mariana, Brazil), after the collapse of the Fundão tailing dam occurred on November 5th, 2015. The research was carried out aiming to provide useful information about ground movement monitoring, planning and risk assessment in the area after the tragic event. The analysis was performed using 46 TerraSAR-X images and a Digital Elevation Model (DEM) obtained by Pleiades data. A-DInSAR processing provided the removal of the atmospheric phase artifacts, baseline related errors, DEM height error estimation and finally the ground displacement determination. The results pointed out that with both techniques it was possible to assess the stability conditions of the Germano mining assets, particularly the main structures of the Germano dam and the detection of small settlements in the mining tailings storage, pointing out that these may be an important components for risk management of open pit mining operations, including tailings dams.

Research paper thumbnail of Spatiotemporal monitoring of surface motions using DInSAR techniques integrated with geological information: a case study of an iron mine in the Amazon region using TerraSAR-X and RADARSAT-2 data

Environmental Earth Sciences, 2018

Instabilities are extremely common in the iron open-pit mines located in the Carajás mineral prov... more Instabilities are extremely common in the iron open-pit mines located in the Carajás mineral province, the world´s largest iron reserves located in the Brazilian Amazon. Due to deep excavations in rock products of low geomechanical quality, heavy precipitation, and blasting practices, mining operations in the area present surface displacements that potentially lead to slope instabilities with several risks (personnel, equipment, mining infrastructure, etc.). This paper presents the results related to the N5E mine based on DInSAR Time Series (DTS) and Persistent Scatterer Interferometry (PSI) using a temporal series of 33 StripMap TerraSAR-X (SM TSX) images, and geological information provided from a 3D photointerpretation of an SM TSX and Ultra-Fine RADARSAT-2 (UF RST) stereo-pair, calibrated with field data. Measurement point (DTS, PSI) results were compared with in situ geodetic survey information (total station/prism measurements) and showed good agreement indicating that most of the mine can be considered stable during the period of the TSX coverage. The highest accumulated displacements were spatially related to a thematic unit mapped as a landfill. For other sectors of the mine, lower deformation rates were related to photointerpreted lineaments related to the Carajás fault system suggesting that geological structures can play a key role in controlling some surface displacements. The investigation demonstrated that the strategy based on the use of DTS and PSI techniques integrated with geological data provided a synoptic view of the deformation process that affected the mine. The approach was relevant for ground displacements monitoring of the study area with DInSAR results compared with in situ geodetic measurements showing good statistical correlation.

Research paper thumbnail of Monitoring of surface movement in a large area of the open pit iron mines (Carajás, Brazil) based on A-DInSAR techniques using TerraSAR-X data

Image and Signal Processing for Remote Sensing XXII, 2016

PSI (Persistent Scatterer Interferometry) analysis of large area is always a challenging task reg... more PSI (Persistent Scatterer Interferometry) analysis of large area is always a challenging task regarding the removal of the atmospheric phase component. This work presents an investigation of ground deformation measurements based on a combination of DInSAR Time-Series (DTS) and PSI techniques, applied in a large area of the open pit iron mines located in Carajás (Brazilian Amazon Region), aiming at detect high rates of linear and nonlinear ground deformation. These mines have presented a historical of instability and surface monitoring measurements over sectors of the mines (pit walls) have been carried out based on ground based radar and total station (prisms). By using a priori information regarding the topographic phase error and phase displacement model derived from DTS, temporal phase unwrapping in the PSI processing and the removal of the atmospheric phases can be performed more efficiently. The DTS results provided the first estimate of the topographic error and the phase displacement model for the PSI analysis. A set of 33 TerraSAR-X-1 images, acquired during the period from March 2012 to April 2013, was used to perform this investigation. The DTS analysis was carried out on a stack of multi-look unwrapped interferogram using an extension of the SVD to obtain the Least-Square solution. The height errors and deformation rates provided by the DTS approach were subtracted from the stack of interferogram to perform the PSI analysis. This procedure improved the capability of the PSI analysis to detect high rates of deformation as well as increased the numbers of point density of the final results. The proposed methodology showed good results for monitoring surface displacement in a large mining area, which is located in a rain forest environment, providing very useful information about the ground movement for planning and risks control.

Research paper thumbnail of Monitoring subsidence of open pit iron mines at Carajás Province based on SBAS interferometric technique using TerraSAR-X data

Remote Sensing Applications: Society and Environment, 2017

This work aims to investigate the potential of the Small Baseline Subset (SBAS) to measure ground... more This work aims to investigate the potential of the Small Baseline Subset (SBAS) to measure ground deformation in five open pit iron mines located in Carajás Mineral Province (Brazilian Amazon Region), characterized by torrential rains, using a set of 33 TerraSAR-X Stripmap images acquired during 1-year, from March 2012 to April 2013. For the interferometric processing, a coherence threshold of 45%, 4 looks, Delaunay Minimum Cost Flow (MCF), with a reference GeoEye-1 DEM were used. The SBAS measurements allowed obtaining a synoptic view of the mine complex, covering the infrastructure and benches, detecting the expected natural settlements on the top of waste piles, as well as detecting the deformation in some benches of one mine (N5W). Overall, the results were consistent with the in situ measurements, and so can be a useful tool for monitoring linear and nonlinear deformation in open pit mines located in a tropical rainforest environment, providing a synoptic view of the ground movement for alarm, planning and mining risk assessment.

Research paper thumbnail of Continuous monitoring of biophysicalEucalyptussp. parameters using interferometric synthetic aperture radar data in P and X bands

Journal of Applied Remote Sensing, 2016

This work aims to verify the applicability of models obtained using interferometric synthetic ape... more This work aims to verify the applicability of models obtained using interferometric synthetic aperture radar (SAR) data for estimation of biophysical Eucalyptus saligna parameters [diameter of breast height (DBH), total height and volume], as a method of continuous forest inventory. In order to obtain different digital elevation models, and the interferometric height (Hint) to retrieve the tree heights, SAR surveying was carried out by an airborne interferometric SAR in two frequencies X and P bands. The study area, located in the Brazilian southeast region (S 22°53′22″/W 45°26′16″ and S 22°53′22″/W 45°26′16″), comprises 128.64 hectares of Eucalyptus saligna stands. The methodological procedures encompassed: forest inventory, topographic surveying, radar mapping, radar processing, and multivariable regression techniques to build Eucalyptus volume, DBH, and height models. The statistical regression pointed out Hint and interferometric coherence as the most important variables for the total height and DBH estimation; for the volume model, however, only the Hint variable was selected. The performance of the biophysical models from the second campaign, two years later (2006), were consistent and its results are very promising for updating annual inventories needed for managing Eucalyptus plantations. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Research paper thumbnail of Monitoring subsidence of waste piles and infrastructures of active open PIT iron mine in the Brazilian Amazon Region using SBAS interferometric technique and TerraSAR-X data

2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), 2015

This paper presents the results of applying SBAS (Small Baseline Subset) differential interferome... more This paper presents the results of applying SBAS (Small Baseline Subset) differential interferometric technique using 33 Stripmap mode images from the TerraSAR-X satellite, over a 1-year monitoring, Stripmap mode, for detection of ground deformation processes in five Carajas open pit iron mines in the state of Pará/Brazil in Amazon region, characterized by torrential rains. The SBAS algorithm was used for the interferometric processing, with coherence threshold of 45%, 4 looks, Delaunay Minimum Cost Flow (MCF), with a reference GeoEye-1 DEM, which allowed obtaining a synoptic view of the mine complex, covering the infrastructure and benches, as well as detecting the deformation in one mine (N5W). In order to monitor the waste piles, a lower coherence value (30%) was necessary. The results obtained were consistent with field work data, including topographic surveying, showing that this technique can be very useful for ground movement alert, planning, and risk assessment.

Research paper thumbnail of Assessment on the improvement of the land use/land cover classification in amazon using alos palsar polarimetric data

Research paper thumbnail of Parameter estimation of rain forest vegetation via polarimetric radar interferometric data

SPIE Proceedings, 2002

Parameter estimation of rain forest vegetation via polarimetric radar interferometric data. [Proc... more Parameter estimation of rain forest vegetation via polarimetric radar interferometric data. [Proceedings of SPIE 4543, 169 (2002)]. Michael Brandfass, Christoph Hofmann, Jose C. Mura, Joao R. Moreira, Konstantinos P. Papathanassiou. Abstract. ...

Research paper thumbnail of Validation of method for estimating interferometric phase offset without the use of ground control points

2012 IEEE International Geoscience and Remote Sensing Symposium, 2012

ABSTRACT This paper analyses the use of an algorithm to estimate the unknown interferometric phas... more ABSTRACT This paper analyses the use of an algorithm to estimate the unknown interferometric phase offsets without the use of ground control points or already calibrated data. Modifications in order to enhance the precision and robustness of the algorithm are presented and the new implementation is validated with X-band airborne SAR data. Furthermore, issues related with the use of the algorithm for P-band datasets are discussed and experimental results are shown for this kind of data. The stability of the algorithm according to the choice of the area of the image used for the estimation and to the choice of the coherence threshold is also verified for both X- and P-band data sets.

Research paper thumbnail of Simulated multipolarized MAPSAR images to distinguish agricultural crops

Scientia Agricola, 2012

Many researchers have shown the potential of Synthetic Aperture Radar (SAR) images for agricultur... more Many researchers have shown the potential of Synthetic Aperture Radar (SAR) images for agricultural applications, particularly for monitoring regions with limitations in terms of acquiring cloud free optical images. Recently, Brazil and Germany began a feasibility study on the construction of an orbital L-band SAR sensor referred to as MAPSAR (Multi-Application Purpose SAR). This sensor provides L-band images in three spatial resolutions and polarimetric, interferometric and stereoscopic capabilities. Thus, studies are needed to evaluate the potential of future MAPSAR images. The objective of this study was to evaluate multipolarized MAPSAR images simulated by the airborne SAR-R99B sensor to distinguish coffee, cotton and pasture fields in Brazil. Discrimination among crops was evaluated through graphical and cluster analysis of mean backscatter values, considering single, dual and triple polarizations. Planting row direction of coffee influenced the backscatter and was divided into two classes: parallel and perpendicular to the sensor look direction. Single polarizations had poor ability to discriminate the crops. The overall accuracies were less than 59 %, but the understanding of the microwave interaction with the crops could be explored. Combinations of two polarizations could differentiate various fields of crops, highlighting the combination VV-HV that reached 78 % overall accuracy. The use of three polarizations resulted in 85.4 % overall accuracy, indicating that the classes pasture and parallel coffee were fully discriminated from the other classes. These results confirmed the potential of multipolarized MAPSAR images to distinguish the studied crops and showed considerable improvement in the accuracy of the results when the number of polarizations was increased.

Research paper thumbnail of Paulo Gurgel

Revista GeoNorte, Mar 11, 2024

Research paper thumbnail of 3D forest structure analysis from optical and LIDAR data

In Austria about half of the entire area (46 %) is covered by forests. The majority of these fore... more In Austria about half of the entire area (46 %) is covered by forests. The majority of these forests are highly managed and controlled in growth. Besides timber production, forest ecosystems play a multifunctional role including climate control, habitat provision and, especially in Austria, protection of settlements. The interrelationships among climatic, ecological, social and economic dimensions of forests require technologies for monitoring both the state and the development of forests. This comprises forest structure, species and age composition and, forest integrity in general. Assessing forest structure for example enables forest managers and natural risk engineers to evaluate whether a forest can fulfil its protective function or not. Traditional methods for assessing forest structure like field inventories and aerial photo interpretation are intrinsically limited in providing spatially continuous information over a large area. The Centre for Geoinformatics (Z_GIS) in collaboration with the National Park Bayerischer Wald, Germany and the Stand Montafon, Austria, has tested and applied advanced approaches of integrating multispectral optical data and airborne laser scanning (ALS) data for (1) forest stand delineation, (2) single tree detection and (3) forest structure analysis. As optical data we used RGBI line scanner data and CIR air-photos. ALS data were raw point data (10 pulses per sqm) and normalised crown models (nCM) at 0.5 m and 1 m resolution. (1) Automated stand delineation was done by (a) translating a key for manual mapping of forest development phases into a rule-based system via object-relationship modelling (ORM); and (b) by performing multi-resolution

Research paper thumbnail of The significance of geological structures on the subsidence phenomenon at the Maceió salt dissolution field (Brazil)

Research paper thumbnail of Análise de Arquiteturas para Processamento de Imagens

Anais do I Simpósio Brasileiro de Arquitetura de Computadores e Processamento Paralelo (SBACC 1987)

Após uma breve introdução sobre as atividades de Processamento de Imagens no INPE, são mostradas ... more Após uma breve introdução sobre as atividades de Processamento de Imagens no INPE, são mostradas as características principais da familia de sistemas SITIM, seguindo-se uma apresentação dos tipos de procedimentos mais utilizados em Processamento de Imagens. São discutidas algumas opções jã testadas para aumento de desempenho do sistema, através do uso de placas aceleradoras, e ao final são apresentadas as perspectivas de desenvolvimento futuro, tanto na área de placas aceleradoras como sistemas baseados em arquitetura paralela, associados a unidades de armazenamento de imagens avançadas.

Research paper thumbnail of Análise De Deformação De Pilhas De Disposição De Estéril Na Província Mineral De Carajás Com Uso De Dados Stripmap Do Satélite Terrasar-X

Revista Brasileira de Cartografia, Apr 27, 2016

A produção mineral brasileira encontra-se entre as maiores do mundo, atuando como um dos pilares ... more A produção mineral brasileira encontra-se entre as maiores do mundo, atuando como um dos pilares da sustentação econômica. O processo minerador envolve, entre outras etapas, a retirada do material sólido sem valor comercial agregado ao minério, denominado estéril. Após sua separação do minério, os estéreis são transportados e dispostos em Pilhas de Disposição de Estéril (PDEs), que sofrem assentamentos durante e após esta operação. A possibilidade de ocorrência de acidentes nessas estruturas e seus impactos ambientais requerem ferramentas efi cientes para o planejamento e prevenção ou minimização de eventuais danos. Neste contexto o Sensoriamento Remoto, em especial o Radar de Abertura Sintética (SAR) e suas técnicas são ferramentas efi cientes para o monitoramento de deformações superfi ciais por permitir uma visão sinóptica de grandes áreas, imageamento periódico e pouca infl uência atmosférica. Assim, o objetivo deste trabalho consistiu em verifi car a aplicabilidade da técnica Interferometria Diferencial por Séries Temporais (DInSAR Time-Series) associada à Intensity Tracking para a detecção de deformações superfi ciais nos taludes das PDEs NWI, W e SIV da Província Mineral de Carajás utilizando imagens TerraSAR-X. As técnicas mostraram potencial na detecção e estimativa do comportamento superfi cial das PDEs. A DInSAR Time-Series apresentou medidas quantitativas com precisão centimétrica, e a Intensity Tracking forneceu resultados de inferência acerca do comportamento superfi cial, recobrindo também regiões com ausência de resultados DInSAR Time-Series, embora com menor precisão.

Research paper thumbnail of Ground displacements revealed by A-DInSAR analysis in the Germano iron mining complex before and after the Fundão Dam collapse using Sentinel-1 data

Journal of Applied Remote Sensing

Abstract. Advanced differential SAR interferometry (A-DInSAR) has been used as an effective monit... more Abstract. Advanced differential SAR interferometry (A-DInSAR) has been used as an effective monitoring tool in mining environments. This work presents an investigation of surface displacement in the Germano iron mining complex (Mariana, Minas Gerais, Brazil), where on November 5, 2015, the Fundão tailings dam collapsed. Initially, the analysis was performed with 14 Sentinel-1 images, acquired from May 8, 2015, to November 4, 2015, and focused on the Fundão dam before its rupture to detect prior signs of surface deformations. The analysis after the Fundão dam collapse was conducted in the Germano area using 43 Sentinel-1 images, acquired from November 16, 2015 to May 15, 2017, and aimed at detecting surface displacement on the remaining infrastructure, the Sela&Tulipa and Selinha dikes and the main Germano tailings dam, which were directly or indirectly affected by the accident. The results reveal precursor signals of surface displacement at the Fundão dam prior to rupture, particularly on the left abutment setback sector where the collapse started according to a witness, reaching accumulated values of up to −60 mm. The results provided by the A-DInSAR analysis after the dam collapse indicate a stability in the Sela&Tulipa and Selinha dikes as well as in the main Germano dam, which is corroborated by in situ topographic measurements. On the auxiliary dikes within the Germano reservoir, accumulated displacement of up to −90 mm caused by settlements and continuous traffic of vehicles was detected. In addition, the detected accumulate displacement within the reservoir showed values of up to −120 mm, in general caused by settlements of the waste dry material due to the inactivity of the mining process. The investigation emphasized the important role that satellite-based A-DInSAR can play in mitigating possible accidents and for operational planning and risk assessment in mining operations.

Research paper thumbnail of Monitoring Horizontal and Vertical Components of SAMARCO Mine Dikes Deformations by DInSAR-SBAS Using TerraSAR-X and Sentinel-1 Data

Mining

This article presents an investigation of ground movement measurements based on a combination of ... more This article presents an investigation of ground movement measurements based on a combination of TerraSAR-X and Sentinel-1 data, in opposite tracks, aiming to detect ground de-formation of the remaining dikes of Germano mine, after the Fundão dam collapse. The differential interferometry technique SBAS (Small Baseline Subset) was applied to obtain the deformation of the surface in different Line of Sight (LoS), in order to carry out the vector decomposition and generate the deformation measurements in the vertical and horizontal directions. A set of 37 single-look complex (SLC) images of TerraSAR-X (TSX), acquired during the period from 19 February 2016 to 15 May 2017, and 37 SLC images of Sentinel-1, acquired from 8 February 2016 to 15 May 2017, were used to perform this investigation. For the TerraSAR-X interferometric processing, a coherence threshold of 40%, 4 looks in range and 2 looks in azimuth, 1200 m of atmospheric filter, and 10 % of max normal baseline of the critical wer...

Research paper thumbnail of Registro Automático De Imagens Sar Interferométricas

Revista Brasileira de Cartografia, Sep 20, 2012

O presente artigo apresenta uma metodologia para registro automático de imagens SAR interferométr... more O presente artigo apresenta uma metodologia para registro automático de imagens SAR interferométricas. Primeiramente as imagens SAR, no formato complexo, são registradas grosseiramente utilizando técnicas de correlação, que resultam em deslocamentos em alcance e azimute, na escala de pixel, aplicados à segunda imagem, sem necessidade de interpolação. Opcionalmente pode ser aplicada a filtragem espectral em azimute nas imagens corregistradas, para a melhoria da coerência interferométrica entre elas. A segunda etapa do registro consiste na aplicação do registro fino, através de uma grade de pequenas janelas distribuídas de forma regular sobre cada uma das imagens onde, para cada janela, é calculado o deslocamento fracionário (da ordem de subpixel) por correlação, resultando em uma grade de deslocamentos, de onde são calculados os polinômios de deformação nos sentidos de alcance e azimute, para a reamostragem da segunda imagem. A partir das imagens corregistradas pode-se aplicar, opcionalmente, a filtragem espectral no sentido de alcance, para a melhoria da coerência interferométrica entre elas. A qualidade do registro final foi avaliada através da análise da imagem de coerência e pelo método dos resíduos aplicados na fase interferométrica gerada a partir das imagens corregistradas. Os algoritmos foram implementados em IDL/ENVI e testados em um par de imagens do SIR-C e um par do ALOS/PALSAR.

Research paper thumbnail of www.mdpi.com/journal/remotesensing Article A Phase-Offset Estimation Method for InSAR DEM Generation Based on Phase-Offset Functions

Abstract. This paper presents a novel method for estimating the absolute phase offset in interfer... more Abstract. This paper presents a novel method for estimating the absolute phase offset in interferometric synthetic aperture radar (SAR) measurements for digital elevation model (DEM) generation. The method is based on “phase-offset functions (POF), ” relating phase offset to topographic height, and are computed for two different overlapping interferometric data acquisitions performed with considerably different incidence angles over the same area of interest. For the purpose of extended mapping, opposite viewing directions are preferred. The two “phase-offset functions ” are then linearly combined, yielding a “combined phase-offset function (CPOF)”. The intersection point of several straight lines (CPOFs), corresponding to different points in the overlap area allows for solving the phase offset for both acquisitions. Aiming at increasing performance and stability, this intersection point is found by means of averaging many points and applying principal component analysis. The method...

Research paper thumbnail of Detecting Clearcut Deforestation Employing Deep Learning Methods and SAR Time Series

2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, 2021

Automating the systematic monitoring of deforestation in the Brazilian biomes has become imperati... more Automating the systematic monitoring of deforestation in the Brazilian biomes has become imperative. In this sense, a promising research field lies upon the exploitation of orbital imaging based on Synthetic Aperture Radar (SAR) sensors, since this technology is less affected by cloud cover, allowing systematic data acquisitions. In addition, the growing availability of with no charge SAR data products enables investigations on the use of time series extracted from this category of instruments, paving the way for more sophisticated temporal analyzes. This work presents the results of a SAR time series classification model designed to identify clearcut deforestation patterns in time, through an Artificial Intelligence approach known as Recurrent Neural Networks. The classification was performed using 5216 samples of Sentinel-1 time series within the Amazon basin, reaching an overall accuracy of 96.74%.

Research paper thumbnail of Advanced DINSAR analysis on dam stability monitoring: A case study in the Germano mining complex (Mariana, Brazil) with SBAS and PSI techniques

Remote Sensing Applications: Society and Environment, 2019

This work presents an investigation of detection and monitoring of surface motions using Advanced... more This work presents an investigation of detection and monitoring of surface motions using Advanced Differential SAR Interferometry (A-DInSAR) with SBAS (Small Baseline Subset) and PSI (Persistent Scatterer Interferometry) techniques in the Germano iron mining complex region (Mariana, Brazil), after the collapse of the Fundão tailing dam occurred on November 5th, 2015. The research was carried out aiming to provide useful information about ground movement monitoring, planning and risk assessment in the area after the tragic event. The analysis was performed using 46 TerraSAR-X images and a Digital Elevation Model (DEM) obtained by Pleiades data. A-DInSAR processing provided the removal of the atmospheric phase artifacts, baseline related errors, DEM height error estimation and finally the ground displacement determination. The results pointed out that with both techniques it was possible to assess the stability conditions of the Germano mining assets, particularly the main structures of the Germano dam and the detection of small settlements in the mining tailings storage, pointing out that these may be an important components for risk management of open pit mining operations, including tailings dams.

Research paper thumbnail of Spatiotemporal monitoring of surface motions using DInSAR techniques integrated with geological information: a case study of an iron mine in the Amazon region using TerraSAR-X and RADARSAT-2 data

Environmental Earth Sciences, 2018

Instabilities are extremely common in the iron open-pit mines located in the Carajás mineral prov... more Instabilities are extremely common in the iron open-pit mines located in the Carajás mineral province, the world´s largest iron reserves located in the Brazilian Amazon. Due to deep excavations in rock products of low geomechanical quality, heavy precipitation, and blasting practices, mining operations in the area present surface displacements that potentially lead to slope instabilities with several risks (personnel, equipment, mining infrastructure, etc.). This paper presents the results related to the N5E mine based on DInSAR Time Series (DTS) and Persistent Scatterer Interferometry (PSI) using a temporal series of 33 StripMap TerraSAR-X (SM TSX) images, and geological information provided from a 3D photointerpretation of an SM TSX and Ultra-Fine RADARSAT-2 (UF RST) stereo-pair, calibrated with field data. Measurement point (DTS, PSI) results were compared with in situ geodetic survey information (total station/prism measurements) and showed good agreement indicating that most of the mine can be considered stable during the period of the TSX coverage. The highest accumulated displacements were spatially related to a thematic unit mapped as a landfill. For other sectors of the mine, lower deformation rates were related to photointerpreted lineaments related to the Carajás fault system suggesting that geological structures can play a key role in controlling some surface displacements. The investigation demonstrated that the strategy based on the use of DTS and PSI techniques integrated with geological data provided a synoptic view of the deformation process that affected the mine. The approach was relevant for ground displacements monitoring of the study area with DInSAR results compared with in situ geodetic measurements showing good statistical correlation.

Research paper thumbnail of Monitoring of surface movement in a large area of the open pit iron mines (Carajás, Brazil) based on A-DInSAR techniques using TerraSAR-X data

Image and Signal Processing for Remote Sensing XXII, 2016

PSI (Persistent Scatterer Interferometry) analysis of large area is always a challenging task reg... more PSI (Persistent Scatterer Interferometry) analysis of large area is always a challenging task regarding the removal of the atmospheric phase component. This work presents an investigation of ground deformation measurements based on a combination of DInSAR Time-Series (DTS) and PSI techniques, applied in a large area of the open pit iron mines located in Carajás (Brazilian Amazon Region), aiming at detect high rates of linear and nonlinear ground deformation. These mines have presented a historical of instability and surface monitoring measurements over sectors of the mines (pit walls) have been carried out based on ground based radar and total station (prisms). By using a priori information regarding the topographic phase error and phase displacement model derived from DTS, temporal phase unwrapping in the PSI processing and the removal of the atmospheric phases can be performed more efficiently. The DTS results provided the first estimate of the topographic error and the phase displacement model for the PSI analysis. A set of 33 TerraSAR-X-1 images, acquired during the period from March 2012 to April 2013, was used to perform this investigation. The DTS analysis was carried out on a stack of multi-look unwrapped interferogram using an extension of the SVD to obtain the Least-Square solution. The height errors and deformation rates provided by the DTS approach were subtracted from the stack of interferogram to perform the PSI analysis. This procedure improved the capability of the PSI analysis to detect high rates of deformation as well as increased the numbers of point density of the final results. The proposed methodology showed good results for monitoring surface displacement in a large mining area, which is located in a rain forest environment, providing very useful information about the ground movement for planning and risks control.

Research paper thumbnail of Monitoring subsidence of open pit iron mines at Carajás Province based on SBAS interferometric technique using TerraSAR-X data

Remote Sensing Applications: Society and Environment, 2017

This work aims to investigate the potential of the Small Baseline Subset (SBAS) to measure ground... more This work aims to investigate the potential of the Small Baseline Subset (SBAS) to measure ground deformation in five open pit iron mines located in Carajás Mineral Province (Brazilian Amazon Region), characterized by torrential rains, using a set of 33 TerraSAR-X Stripmap images acquired during 1-year, from March 2012 to April 2013. For the interferometric processing, a coherence threshold of 45%, 4 looks, Delaunay Minimum Cost Flow (MCF), with a reference GeoEye-1 DEM were used. The SBAS measurements allowed obtaining a synoptic view of the mine complex, covering the infrastructure and benches, detecting the expected natural settlements on the top of waste piles, as well as detecting the deformation in some benches of one mine (N5W). Overall, the results were consistent with the in situ measurements, and so can be a useful tool for monitoring linear and nonlinear deformation in open pit mines located in a tropical rainforest environment, providing a synoptic view of the ground movement for alarm, planning and mining risk assessment.

Research paper thumbnail of Continuous monitoring of biophysicalEucalyptussp. parameters using interferometric synthetic aperture radar data in P and X bands

Journal of Applied Remote Sensing, 2016

This work aims to verify the applicability of models obtained using interferometric synthetic ape... more This work aims to verify the applicability of models obtained using interferometric synthetic aperture radar (SAR) data for estimation of biophysical Eucalyptus saligna parameters [diameter of breast height (DBH), total height and volume], as a method of continuous forest inventory. In order to obtain different digital elevation models, and the interferometric height (Hint) to retrieve the tree heights, SAR surveying was carried out by an airborne interferometric SAR in two frequencies X and P bands. The study area, located in the Brazilian southeast region (S 22°53′22″/W 45°26′16″ and S 22°53′22″/W 45°26′16″), comprises 128.64 hectares of Eucalyptus saligna stands. The methodological procedures encompassed: forest inventory, topographic surveying, radar mapping, radar processing, and multivariable regression techniques to build Eucalyptus volume, DBH, and height models. The statistical regression pointed out Hint and interferometric coherence as the most important variables for the total height and DBH estimation; for the volume model, however, only the Hint variable was selected. The performance of the biophysical models from the second campaign, two years later (2006), were consistent and its results are very promising for updating annual inventories needed for managing Eucalyptus plantations. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Research paper thumbnail of Monitoring subsidence of waste piles and infrastructures of active open PIT iron mine in the Brazilian Amazon Region using SBAS interferometric technique and TerraSAR-X data

2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), 2015

This paper presents the results of applying SBAS (Small Baseline Subset) differential interferome... more This paper presents the results of applying SBAS (Small Baseline Subset) differential interferometric technique using 33 Stripmap mode images from the TerraSAR-X satellite, over a 1-year monitoring, Stripmap mode, for detection of ground deformation processes in five Carajas open pit iron mines in the state of Pará/Brazil in Amazon region, characterized by torrential rains. The SBAS algorithm was used for the interferometric processing, with coherence threshold of 45%, 4 looks, Delaunay Minimum Cost Flow (MCF), with a reference GeoEye-1 DEM, which allowed obtaining a synoptic view of the mine complex, covering the infrastructure and benches, as well as detecting the deformation in one mine (N5W). In order to monitor the waste piles, a lower coherence value (30%) was necessary. The results obtained were consistent with field work data, including topographic surveying, showing that this technique can be very useful for ground movement alert, planning, and risk assessment.

Research paper thumbnail of Assessment on the improvement of the land use/land cover classification in amazon using alos palsar polarimetric data

Research paper thumbnail of Parameter estimation of rain forest vegetation via polarimetric radar interferometric data

SPIE Proceedings, 2002

Parameter estimation of rain forest vegetation via polarimetric radar interferometric data. [Proc... more Parameter estimation of rain forest vegetation via polarimetric radar interferometric data. [Proceedings of SPIE 4543, 169 (2002)]. Michael Brandfass, Christoph Hofmann, Jose C. Mura, Joao R. Moreira, Konstantinos P. Papathanassiou. Abstract. ...

Research paper thumbnail of Validation of method for estimating interferometric phase offset without the use of ground control points

2012 IEEE International Geoscience and Remote Sensing Symposium, 2012

ABSTRACT This paper analyses the use of an algorithm to estimate the unknown interferometric phas... more ABSTRACT This paper analyses the use of an algorithm to estimate the unknown interferometric phase offsets without the use of ground control points or already calibrated data. Modifications in order to enhance the precision and robustness of the algorithm are presented and the new implementation is validated with X-band airborne SAR data. Furthermore, issues related with the use of the algorithm for P-band datasets are discussed and experimental results are shown for this kind of data. The stability of the algorithm according to the choice of the area of the image used for the estimation and to the choice of the coherence threshold is also verified for both X- and P-band data sets.

Research paper thumbnail of Simulated multipolarized MAPSAR images to distinguish agricultural crops

Scientia Agricola, 2012

Many researchers have shown the potential of Synthetic Aperture Radar (SAR) images for agricultur... more Many researchers have shown the potential of Synthetic Aperture Radar (SAR) images for agricultural applications, particularly for monitoring regions with limitations in terms of acquiring cloud free optical images. Recently, Brazil and Germany began a feasibility study on the construction of an orbital L-band SAR sensor referred to as MAPSAR (Multi-Application Purpose SAR). This sensor provides L-band images in three spatial resolutions and polarimetric, interferometric and stereoscopic capabilities. Thus, studies are needed to evaluate the potential of future MAPSAR images. The objective of this study was to evaluate multipolarized MAPSAR images simulated by the airborne SAR-R99B sensor to distinguish coffee, cotton and pasture fields in Brazil. Discrimination among crops was evaluated through graphical and cluster analysis of mean backscatter values, considering single, dual and triple polarizations. Planting row direction of coffee influenced the backscatter and was divided into two classes: parallel and perpendicular to the sensor look direction. Single polarizations had poor ability to discriminate the crops. The overall accuracies were less than 59 %, but the understanding of the microwave interaction with the crops could be explored. Combinations of two polarizations could differentiate various fields of crops, highlighting the combination VV-HV that reached 78 % overall accuracy. The use of three polarizations resulted in 85.4 % overall accuracy, indicating that the classes pasture and parallel coffee were fully discriminated from the other classes. These results confirmed the potential of multipolarized MAPSAR images to distinguish the studied crops and showed considerable improvement in the accuracy of the results when the number of polarizations was increased.