Jean-claude Souyris - Academia.edu (original) (raw)

Papers by Jean-claude Souyris

IGARSS 2003. 2003 IEEE International Geoscience and Remote Sensing Symposium. Proceedings (IEEE Cat. No.03CH37477), 2003

In a previous study , the joint use of Synthetic Aperture Radar (SAR) image magnitude and phase h... more In a previous study , the joint use of Synthetic Aperture Radar (SAR) image magnitude and phase has been assessed in the context of target detection. The two-looks Internal Hermitian Product (2L-IHP), based on a correlation between sub-looks of a single look complex (slc) radar image, was introduced. It has been applied on an airborne radar image including deterministic targets deployed in a natural environment. The 2L-IHP was shown to increase the target environment contrast.

IGARSS 2003. 2003 IEEE International Geoscience and Remote Sensing Symposium. Proceedings (IEEE Cat. No.03CH37477), 2003

TOPSAR (Terrain Observation with Progressive Scan) is as new wide swath acquisition mode which is... more TOPSAR (Terrain Observation with Progressive Scan) is as new wide swath acquisition mode which is planned to be used by the forthcoming ESA SAR sensor Sentinel-1. This system allows achieving similar swath coverage than the ScanSAR mode but with an improved azimuth resolution by rotating the antenna from backward to forward at a constant speed. Moreover it overcomes two of the main drawbacks of Scansar images, amplitude scalloping and the azimuth varying ambiguities. The main objective of the study presented is the analysis and understanding of the characteristics of the TOPSAR new wide swath acquisition mode. Special emphasis has also been brought on the evaluation of its interferometric performance. The following paper reports the results of those analyses.

IGARSS 2008 - 2008 IEEE International Geoscience and Remote Sensing Symposium, 2008

The ocean wave spectrum provides information on the distribution of wave energy (or wave height) ... more The ocean wave spectrum provides information on the distribution of wave energy (or wave height) with respect to wavelength and wave propagation direction. These features are of main interests for ocean wave monitoring and forecast. However, wave spectra are not widely available. Nowadays, Synthetic Aperture Radars are the only space sensors that provide part of the wave spectra. Yet, due to azimuth cut-off related to smearing imaging effects over a moving surface, only the largest waves can be detected (approximately above 200 m in wavelength). The design of a Ku-Band airborne wave "spectrometer" has been first proposed and used by Jackson . An airborne C-Band system called RESSAC (and renamed STORM today) was developed and used in France for the same purpose. The spaceborne concept first proposed by Jackson et al was further studied in France and Europe with the VagSAT [8] and SWIMSAT [1] satellite mission proposals, which were not selected at that time. This spaceborne wave spectrometer concept is now taken back by the SWIM (Surface Wave Investigation and Monitoring) payload on the CFOSAT (Chinese French Ocean SATellite) mission, to be launched around 2012. SWIM, a follow-on concept of VagSAT and SWIMSAT payloads, aims at measuring directional wave spectra on a 180 km wide swath. SWIM is a real aperture radar in Ku-band pointing sequentially at six different incidences (see . SWIM designs will be extensively described in a side paper submitted to the same conference . Here, the SWIM concept will be briefly described in order to give the key concepts which are useful to readers' understanding. This paper will be focused on the performance assessment and on trade-offs between payload feasibility and performance. Performance assessment are made through simulations, implying the development of an efficient simulation tool. This tool is an end-to-end simulator (i.e. from the surface to the wave spectrum estimate). Therefore it enables to simulate the sensor parameters and geometry, the signal acquisition, the on-board processings and part of the onground processings. The qualification of the performance is made with criteria defined on the estimated wave spectra regarding the expected theoretical one. This simulator is based on previous work developed for VagSAT [8] and it has been extended to the SWIM configuration. The main steps of the simulation are: -surface simulation from analytical wave spectrum, -backscattered intensity simulation (including sensor impulse response), -on-board processing (averaging, migration correction, modulation estimation), -inversion of mean modulation to get the wave spectrum, -quality estimation. In this paper, we will first describe the main improvements made from the VagSAT version. Illustrations on performances obtained with different sea states will be given.

2010 IEEE International Geoscience and Remote Sensing Symposium, 2010

SWIM is a Ku-band radar designed for wave directional spectrum estimation. This radar operates at... more SWIM is a Ku-band radar designed for wave directional spectrum estimation. This radar operates at six incidence angles (from 0° to 10°) with a complete azimuth scanning covering a swath of 180 km. The phase B (addressing preliminary design) of SWIM is currently under finalization. In, the preliminary design and associated performance analysis have been published taking into account the

2011 IEEE International Geoscience and Remote Sensing Symposium, 2011

... References [1] N. Stacy, D. Crisp, A. Goh, D. Badger and M. Preiss, Polarimetric Analysis of... more ... References [1] N. Stacy, D. Crisp, A. Goh, D. Badger and M. Preiss, Polarimetric Analysis of Fine Resolution X-Band SAR Sea Clutter Data, Proc. IGARSS'05, Vol.4, pp.2787-2790, 2005. [2] Masuko M., Okamoto K. Shimada ...

IEEE International IEEE International IEEE International Geoscience and Remote Sensing Symposium, 2004. IGARSS '04. Proceedings. 2004, 2004

An important question with respect to the performance of the interferometric cartwheel and simila... more An important question with respect to the performance of the interferometric cartwheel and similar bistatic SAR systems, is whether the ambiguities combine coherently and introduce artifacts in the resulting interferograms. We here review the theoretical behavior of range and azimuth ambiguities and extend the description to the case of non-zero Doppler processing. Simulation results confirm that ambiguities cannot significantly degrade

2010 IEEE International Geoscience and Remote Sensing Symposium, 2010

The principal instrument of the SWOT (Surface Water and Ocean Topography) altimetry mission is Ka... more The principal instrument of the SWOT (Surface Water and Ocean Topography) altimetry mission is KaRIn, a Ka-band interferometric SAR system operating on near-nadir swaths on both sides of the satellite track. This article briefly describes the measurement principle, the processing steps and the specificities of the interferometric SAR data of KaRIn as compared to conventional spaceborne SAR systems.

2009 IEEE International Geoscience and Remote Sensing Symposium, 2009

Global warning is now known to be the major environmental issue mankind will have to face in the ... more Global warning is now known to be the major environmental issue mankind will have to face in the next decade. Monitoring of vegetation and biomass is clearly an essential piece of information required at all levels ranging from the scientific studies to understand and forecast, to the political actors and government leaders responsible for drafting remediation policies and evaluating their impact. Microwave remote sensing with the low-frequency SAR technique can provide a useful characterization of forest (spatial coverage, species, density, height…) at a global scale, relying on the all-weather imaging capabilities of SAR linked with the significant penetration of the low-frequency EM wave in the canopy. The published techniques for forest characterization from low frequency SAR data include radiometry inversion, polarimetric inversion based on the anisotropy parameters and PolInSAR Random Volume Over Ground inversion. In this paper, we will more specifically concentrate on the PolSAR technique and the impact of ionospheric effect.

ABSTRACT/RESUME A polarimetric and PolInSAR analysis has been con- ducted on the Nezer forest (So... more ABSTRACT/RESUME A polarimetric and PolInSAR analysis has been con- ducted on the Nezer forest (Southern France) at L and P band on high resolution SAR data acquired with the ONERA RAMSES system in January 2004. The dataset was investigated for its potential for re- trieval of forest parameters from SAR data using three different techniques: •,Radiometric,inversion from,the cross-polarized term, •,PolInSAR

Geoscience and Remote Sensing IEEE International Symposium, 2007

In this paper, we analyse the potential associated with a compact polarimetry (CP) P band spacebo... more In this paper, we analyse the potential associated with a compact polarimetry (CP) P band spaceborne SAR system. Indeed, this architecture allows polarimetric acquisition without the usual reduction in swath. The CP data is shown to be almost equivalent to the full polarimetric data over extended targets, and the PolInSAR analysis can be performed without a significant loss of performance.

RESUME The overall objective of this paper is to assess SA R compact polarimetry (CP) architectur... more RESUME The overall objective of this paper is to assess SA R compact polarimetry (CP) architectures based on mixed polarization basis measurements allowing for an implementation on satellite at reduced cost. The potential applications include Earth observation or planetary Science. The performance assessment both concerns the level of information preserved in comparison with full polarimetry (FP), and the concurrent space

IGARSS 2008 - 2008 IEEE International Geoscience and Remote Sensing Symposium, 2008

In spaceborne SAR, a single-polarization on transmit has, over full polarization, the advantage o... more In spaceborne SAR, a single-polarization on transmit has, over full polarization, the advantage of a double swath due to SAR system design issues. Without getting into the details deserving by themselves a full publication, we can just observe the swath characteristics associated with ALOS PALSAR dual-pol and full-polarization modes. This increased coverage has a direct impact on the revisit time, which is always a major drive for the Earth Observing community. The options chosen up to now for current dual-pol system designs (or single-polarization on transmit) rely on a linear polarization on transmit, with two orthogonal polarizations on receive. Souyris [1] in an earlier paper proposed a more pertinent alternative for the selection of the transmit polarization leading to a better characterization of the scattering mechanisms. In a previous paper, the analysis was pursued in more depth by including the effect of the ionosphere on the wave propagation and extending the applications to polarimetric interferometry (PolInSAR). A compact pol mode was proposed where the transmit polarization is circular while the only constraint on the two receiving polarizations is independence. Both the polarimetric SAR applications and the PolInSAR applications in the context of this compact polarimetry (CP) mode were explored. A pseudo covariance matrix can be reconstructed for distributed target and was shown to be very similar to the full polarimetric (FP) covariance matrix. A PolInSAR vegetation height inversion for P Band was presented and applied to the CP data with a level of performance similar to the one associate to FP (1.2m RMS Height on the RAMSES dataset over the Landes forest). A procedure was developed to correct for the ionospheric effects for PolInSAR acquisition in FP or CP mode and the simulation on airborne data proves the procedure to be efficient and robust. In this paper, we extend the analysis of the CP mode to other sites and other datasets. For PolInSAR inversion, CP mode could be very dependant of the dominant scattering mechanisms. The double bounce effect, which is an essential element of the scattering when topography is flat, has an interesting effect on the PolInSAR behavior of forest: When the DB is present, it is usually relatively strong and focused the bottom to the trunks, lowering the overall scattering phase center. In a CP polarimetry mode, the observed polarization states are only a subset of the FP set. In the unitary circle, the complex interferometric coherences associated with a given area describe a convex region when the polarization state varies. In the hypothesis of the Random Volume Over Ground model, this region is a line and the inversion relies on the accurate estimation of this line and its intersections with the unitary circle. In a CP mode, the length of the line will therefore be shorter, potentially creating a less accurate estimate of the needed line. The previous study explored the behavior of CP on the Nezer forest which has no topography. In this study, other sites will be included where topography is present and FP PolInSAR estimation will be compared to CP PolInSAR inversion.

2010 IEEE International Geoscience and Remote Sensing Symposium, 2010

Sensors, 2006

The main limitations of standard nadir-looking radar altimeters have been known for long. They in... more The main limitations of standard nadir-looking radar altimeters have been known for long. They include the lack of coverage (intertrack distance of typically 150 km for the T/P / Jason tandem), and the spatial resolution (typically 2 km for T/P and Jason), expected to be a limiting factor for the determination of mesoscale phenomena in deep ocean. In this context, various solutions using off-nadir radar interferometry have been proposed by Rodriguez and al to give an answer to oceanographic mission objectives. This paper addresses the performances study of this new generation of instruments, and dedicated mission. A first approach is based on the Wide-Swath Ocean Altimeter (WSOA) intended to be implemented onboard Jason-2 in 2004 but now abandoned. Every error domain has been checked: the physics of the measurement, its geometry, the impact of the platform and external errors like the tropospheric and ionospheric delays. We have especially shown the strong need to move to a sun-synchronous orbit and the non-negligible impact of Sensors 2006, 6 165 propagation media errors in the swath, reaching a few centimetres in the worst case. Some changes in the parameters of the instrument have also been discussed to improve the overall error budget. The outcomes have led to the definition and the optimization of such an instrument and its dedicated mission.

During the rainy season, the abundance of mosquitoes over the Ferlo Region (Senegal) is linked to... more During the rainy season, the abundance of mosquitoes over the Ferlo Region (Senegal) is linked to dynamic, vegetation cover and turbidity of temporary and relatively small ponds. They create a variable environment where mosquitoes can contribute to diffusion and transmission of diseases. A previous work [1] assessed the use of optical SPOT-5 high-resolution images (~ 10m spatial resolution), which allowed for detailed assessment of spatio-temporal evolution of ponds.

IEEE Transactions on Geoscience and Remote Sensing, 2000

... Gerald Dibarboure, Sylvie Labroue, Michael Ablain, Roger Fjørtoft, Alain Mallet, Juliette Lam... more ... Gerald Dibarboure, Sylvie Labroue, Michael Ablain, Roger Fjørtoft, Alain Mallet, Juliette Lambin, and Jean-Claude Souyris Abstract—This paper gives an overview of an empirical cross-calibration technique developed for the Surface Water Ocean Topography mission (SWOT). ...

IEEE Transactions on Geoscience and Remote Sensing, 2000

The objective of this paper is twofold: first, to assess the potential of radar data for tropical... more The objective of this paper is twofold: first, to assess the potential of radar data for tropical vegetation cartography and, second, to evaluate the contribution of different polarimetric indicators that can be derived from a fully polarimetric data set. Because of its ability to take numerous and heterogeneous parameters into account, such as the various polarimetric indicators under consideration, a support vector machine (SVM) algorithm is used in the classification step. The contribution of the different polarimetric indicators is estimated through a greedy forward and backward method. Results have been assessed with AIRSAR polarimetric data polarimetric data acquired over a dense tropical environment. The results are compared to those obtained with the standard Wishart approach, for single frequency and multifrequency bands. It is shown that, when radar data do not satisfy the Wishart distribution, the SVM algorithm performs much better than the Wishart approach, when applied to an optimized set of polarimetric indicators.

IEEE Transactions on Geoscience and Remote Sensing, 2003

... pedestal characterizes the sharing between polarized and depolarized energy [17]. This type o... more ... pedestal characterizes the sharing between polarized and depolarized energy [17]. This type of physical explanation applies ... double-bounce mechanism. Fig. ... a dominant (red) indicates a odd number of reflections; a dominant (green) indicates dipole-like scattering; a dominant ...

IEEE Transactions on Geoscience and Remote Sensing, 2000

In spaceborne synthetic aperture radar (SAR), a single-polarization on-transmit offers twice the ... more In spaceborne synthetic aperture radar (SAR), a single-polarization on-transmit offers twice the swath width compared to full polarization. This is linked to SAR system design issues, and, without getting into the technical details deserving by themselves a full paper, we can just mention the swath characteristics of ALOS PALSAR (the Advanced Land Observing Satellite, Phased Array L-Band Synthetic Aperture Radar),