References of "De Rauw, Dominique"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailSplit-Band Interferometry-Assisted Phase Unwrapping for the Phase Ambiguities Correction
Libert, Ludivine ULiege; De Rauw, Dominique ULiege; d'Oreye, Nicolas et al

in Remote Sensing (2017), 9(9),

Split-Band Interferometry (SBInSAR) exploits the large range bandwidth of the new generation of synthetic aperture radar (SAR) sensors to process images at subrange bandwidth. Its application to an ... [more ▼]

Split-Band Interferometry (SBInSAR) exploits the large range bandwidth of the new generation of synthetic aperture radar (SAR) sensors to process images at subrange bandwidth. Its application to an interferometric pair leads to several lower resolution interferograms of the same scene with slightly shifted central frequencies. When SBInSAR is applied to frequency-persistent scatterers, the linear trend of the phase through the stack of interferograms can be used to perform absolute and spatially independent phase unwrapping. While the height computation has been the main concern of studies on SBInSAR so far, we propose instead to use it to assist conventional phase unwrapping. During phase unwrapping, phase ambiguities are introduced when parts of the interferogram are separately unwrapped. The proposed method reduces the phase ambiguities so that the phase can be connected between separately unwrapped regions. The approach is tested on a pair of TerraSAR-X spotlight images of Copahue volcano, Argentina. In this framework, we propose two new criteria for the frequency-persistent scatterers detection, based respectively on the standard deviation of the slope of the linear regression and on the phase variance stability, and we compare them to the multifrequency phase error. Both new criteria appear to be more suited to our approach than the multifrequency phase error. We validate the SBInSAR-assisted phase unwrapping method by artificially splitting a continuous phase region into disconnected subzones. Despite the decorrelation and the steep topography affecting the volcanic test region, the expected phase ambiguities are successfully recovered whatever the chosen criterion to detect the frequency-persistent scatterers. Comparing the aspect ratio of the distributions of the computed phase ambiguities, the analysis shows that the phase variance stability is the most efficient criterion to select stable targets and the slope standard deviation gives satisfactory results. [less ▲]

Detailed reference viewed: 25 (2 ULiège)
Full Text
See detailThe Split-Band Interferometry Approach to Determine the Phase Unwrapping Offset
Libert, Ludivine ULiege; De Rauw, Dominique ULiege; d'Oreye, Nicolas et al

Poster (2017, June)

This poster presents an approach based on the Split-Band Interferometry to solve the ambiguities introduced during the phase unwrapping of separate regions.

Detailed reference viewed: 24 (4 ULiège)
Full Text
See detailA step-by-step recipe of band-spli3ng technique for isola8on of ionospheric signal in L-band InSAR data
Furuya, Masato; Suzuki, Takato; De Rauw, Dominique ULiege

Poster (2016, December 15)

Ionospheric signals are widely regarded as nuisance in low- frequency InSAR data, and thus a variety of correction techniques have been proposed. Although band-splitng of range spectrum has been shown to ... [more ▼]

Ionospheric signals are widely regarded as nuisance in low- frequency InSAR data, and thus a variety of correction techniques have been proposed. Although band-splitng of range spectrum has been shown to be effectve (Brcic et al., 2010; Rosen et al., 2010; Gomba et al., 2015), the band- spliting technique seems to have not been widely used. Whereas this would be partly because the impacts of ionosphere on InSAR data are not necessarily serious, we consider that this could be also because the details of the technique have not been reproducibly shown. Here we show our step-by-step recipe of the band-spliting technique, and demonstrate two case studies that reveal the effectiveness of the technique. [less ▲]

Detailed reference viewed: 29 (4 ULiège)
Full Text
Peer Reviewed
See detailA TOPSAR Processor based on the Omega-K Algorithm: Evaluation with Sentinel-1 Data
Kirkove, Murielle ULiege; Orban, Anne ULiege; De Rauw, Dominique ULiege et al

in A TOPSAR Processor based on the Omega-K Algorithm: Evaluation with Sentinel-1 Data (2016, June)

This paper presents a processor for the TOPS (Terrain Observation by Progressive Scans) imaging mode. TOPS signals have two characteristics that make the use of Stripmap SAR processors inconvenient, i.e ... [more ▼]

This paper presents a processor for the TOPS (Terrain Observation by Progressive Scans) imaging mode. TOPS signals have two characteristics that make the use of Stripmap SAR processors inconvenient, i.e., azimuth frequency and azimuth time foldings. This paper describes a processor based on the Omega-K (Ω-k) algorithm, combined with pre-processing by frequency unfolding and post-processing by time unfolding. Raw data acquired by Sentinel-1 have been used to assess the quality of image reconstruction [less ▲]

Detailed reference viewed: 77 (4 ULiège)
Full Text
See detailThe RESIST Project: a Study of Geohazards in the Kivu Basin Region using ground- and space borne Techniques
Libert, Ludivine ULiege; d'Oreye, Nicolas; Kervyn, François et al

Poster (2015, September)

Presentation of the goals and means of the RESIST project

Detailed reference viewed: 14 (1 ULiège)
Full Text
See detailSplit-Band Interferometric SAR Processing Using TanDEM-X Data
De Rauw, Dominique ULiege; Kervyn, François; d'Oreye, Nicolas et al

in ESA SP-731 (2015, March)

Most recent SAR sensors use wide band signals to achieve metric range resolution. One can also take advantage of wide band to split it into sub-bands and generate several lower-resolution images, centered ... [more ▼]

Most recent SAR sensors use wide band signals to achieve metric range resolution. One can also take advantage of wide band to split it into sub-bands and generate several lower-resolution images, centered on slightly different frequencies, from a single acquisition. This process, named Multi Chromatic Analysis (MCA) corresponds to performing a spectral analysis of SAR images. Split-Band SAR interferometry (SBInSAR) is based on spectral analysis performed on each image of an InSAR pair, yielding a stack of sub-band interferograms. Scatterers keeping a coherent behaviour in each sub-band interferogram show a phase that varies linearly with the carrier frequency, the slope being proportional to the absolute optical path difference. This potentially solves the problems of phase unwrapping on a pixel-per-pixel basis. In this paper, we present an SBInSAR processor and its application using TanDEM-X data over the Nyiragongo volcano. [less ▲]

Detailed reference viewed: 311 (17 ULiège)
Full Text
See detailSpectral coherence applied to vessel tracking
De Rauw, Dominique ULiege; Barbier, Christian ULiege

in Radar, IEEE International Conference (2014, October)

Multi-Chromatic or spectral Analysis (MCA) of SAR images consists in splitting wide band SAR signals into sub-bands to generate several lower resolution images from a single acquisition. This splitting ... [more ▼]

Multi-Chromatic or spectral Analysis (MCA) of SAR images consists in splitting wide band SAR signals into sub-bands to generate several lower resolution images from a single acquisition. This splitting allows performing a spectral analysis of observed scatterers. Spectral coherence is derived by computing the coherence between sub-images issued from a single SAR acquisition. It was shown that in the presence of a random distribution of surface scatterers, spectral coherence is proportional to sub-band intersection of sub-images. This model is fully verified when observing spectral coherence on open seas areas. If the scatterers distribution departs from this distribution, like for manmade structures, spectral coherence may be preserved to a certain degree. We investigated the spectral coherence to perform vessel detection on a sea background by using spotlight images acquired on the Venice Lagoon. Sea background tends to lead to very low spectral coherence while this latter is preserved on the targeted vessels, even for very small ones. A first analysis shows that all vessels observable in intensity images are easily detected in the spectral coherence images which can be used as a complementary information channel to constrain vessel detection. [less ▲]

Detailed reference viewed: 21 (3 ULiège)
Full Text
Peer Reviewed
See detailMulti-Chromatic Analysis of SAR Images for Coherent Target Detection
Bovenga, Fabio; Barbier, Christian ULiege; De Rauw, Dominique ULiege et al

in Remote Sensing (2014), 6

This work investigates the possibility of performing target analysis through the Multi-Chromatic Analysis (MCA), a technique that basically explores the information content of sub-band images obtained by ... [more ▼]

This work investigates the possibility of performing target analysis through the Multi-Chromatic Analysis (MCA), a technique that basically explores the information content of sub-band images obtained by processing portions of the range spectrum of a synthetic aperture radar (SAR) image. According to the behavior of the SAR signal at the different sub-bands, MCA allows target classification. Two strategies have been experimented by processing TerraSAR-X images acquired over the Venice Lagoon, Italy: one exploiting the phase of interferometric sub-band pairs, the other using the spectral coherence derived by computing the coherence between sub-band images of a single SAR acquisition. The first approach introduces the concept of frequency-persistent scatterers (FPS), which is complementary to that of the time-persistent scatterers (PS). FPS and PS populations have been derived and analyzed to evaluate the respective characteristics and the physical nature of the targets. Spectral coherence analysis has been applied to vessel detection, according to the property that, in presence of a random distribution of surface scatterers, as for open sea surfaces, spectral coherence is expected to be proportional to sub-band intersection, while in presence of manmade structures it is preserved anyhow. First results show that spectral coherence is well preserved even for very small vessels, and can be used as a complementary information channel to constrain vessel detection in addition to classical Constant False Alarm Rate techniques based on the sole intensity channel. [less ▲]

Detailed reference viewed: 77 (9 ULiège)
Full Text
Peer Reviewed
See detailWide band SAR sub-band splitting and inter-band coherence measurements
De Rauw, Dominique ULiege; Orban, Anne ULiege; Barbier, Christian ULiege

in Remote Sensing Letters (2010), 1(3), 133-140

Range resolution of SAR images is determined by transmitted radar signal bandwidth. Most recent SAR sensors use wide band signals in order to achieve metric range resolution, whereas metric azimuth ... [more ▼]

Range resolution of SAR images is determined by transmitted radar signal bandwidth. Most recent SAR sensors use wide band signals in order to achieve metric range resolution, whereas metric azimuth resolution can be achieved in spotlight mode. As an example, ENVISAT ASAR sensor uses a 15-MHz bandwidth chirp whereas TerraSAR-X spotlight mode uses signals having a 150-MHz bandwidth leading to a potentially 10 times higher resolution. One can also take advantage of wide band to split the full band into sub-bands and generate several lower resolution images from a single acquisition, each being centred on slightly different frequencies. These sub-images can then be used in a classical interferometric process to measure inter-band coherence of a given scene. This inter-band coherence reveals scatterers keeping a stable-phase behaviour along with frequency shift. A simple coherence model derived from Zebker model for randomly distributed surface scatterers is proposed. Examples are presented, showing that scatterers can have a behaviour that deviates from the model, leading to a new information channel. [less ▲]

Detailed reference viewed: 99 (16 ULiège)
Full Text
See detailAlignement et optimisation d'un simulateur solaire d'une configuration de 1SC à une configuration à 10SC.
De Rauw, Dominique ULiege; Mazy, Emmanuel ULiege; Stockman, Yvan ULiege et al

Conference (2009, November 18)

Ce papier décrit les tâches réalisées dans le cadre d’un projet de modification du simulateur solaire de l’ESA afin de l’adapter et le faire passer d’une configuration où le flux est de une constante ... [more ▼]

Ce papier décrit les tâches réalisées dans le cadre d’un projet de modification du simulateur solaire de l’ESA afin de l’adapter et le faire passer d’une configuration où le flux est de une constante solaire vers une configuration à 10 constantes solaires. Nous exposons les tâches réalisées par le Centre Spatial de Liège en ce qui concerne la modélisation et la simulation des configurations ainsi que les éléments mis au point pour l’alignement des miroirs du simulateur solaire et pour la mesure d’uniformité de flux. [less ▲]

Detailed reference viewed: 56 (10 ULiège)
Full Text
Peer Reviewed
See detailInter-band Coherence of Split Wide Band SAR Images; A Potentially New Information Channel
De Rauw, Dominique ULiege; Orban, Anne ULiege; Barbier, Christian ULiege

in EARSel Newsletter (2009), 79

Recently-launched SAR sensors like TerraSAR-X or CosmoSkyMed are equipped with wide bandwidth radar signal emitters. Working at large bandwidth allows reaching metric range resolution, which combined with ... [more ▼]

Recently-launched SAR sensors like TerraSAR-X or CosmoSkyMed are equipped with wide bandwidth radar signal emitters. Working at large bandwidth allows reaching metric range resolution, which combined with spotlight mode, leads to Very High Resolution (VHR) SAR imagery. One can also take advantage of this wide band to split it into sub-bands and generate several lower resolution images from the same master one, each centered on a slightly different cen- tral frequency. These sub-images can then be used in a classical interferometric process to estimate inter- band coherence of a given scene. This inter-band coherence reveals scatterers keeping a stable phase behaviour along with frequency shift. In this paper, a simple model derived from Zebker model for randomly distributed surface scatterers is proposed and examples are pre- sented showing that scatterers can have a behaviour that deviates from the model, leading to a new information channel. [less ▲]

Detailed reference viewed: 68 (12 ULiège)
Full Text
Peer Reviewed
See detailA proof of concept of Iterative DSM improvement through SAR scene simulation
De Rauw, Dominique ULiege

in ISPRS Journal of Photogrammetry & Remote Sensing (2009), XXXVIII(3/W4), 121-126

In Very High Resolution (VHR) Synthesis Aperture Radar (SAR) context, very fine and accurate georeferencing and geoprojection processes are required. Both operations are only applicable if accurate local ... [more ▼]

In Very High Resolution (VHR) Synthesis Aperture Radar (SAR) context, very fine and accurate georeferencing and geoprojection processes are required. Both operations are only applicable if accurate local heights are known. 3D information may be derived from SAR interferometry (InSAR), But in VHR context, InSAR reveals to be inaccurate mostly due to phase unwrapping problems and to phase/height noise. Generated InSAR Digital Surface Models (DSM) can only be considered as a first good approximation of the observed surface. Therefore, we proposed to start from the InSAR DSM, to project it on ground range on a given datum, to model the observed scene using this projected DSM, then to simulate in slant range the intensity image issued from this structure model. Comparison between simulated and observed intensity image can then be used as a criterion to modify and improve the considered underlying DSM. In this paper, we present the different steps of the proposed approach and results obtained so far, showing that the proposed process can be run iteratively to modify the DSM and reach a stable solution. [less ▲]

Detailed reference viewed: 47 (2 ULiège)
Full Text
See detailAutomated Phase Map Referencing Against Historic Map Data
Groves, Roger; De Rauw, Dominique ULiege; Thizy, Cédric ULiege et al

in Osten, W.; Kujawinska, M. (Eds.) Fringe 2009 (2009, September)

Holography and shearography techniques are in common use for precise measurements in high technology industries, such as aerospace, automotive, precision manufacturing and for the structural diagnostics ... [more ▼]

Holography and shearography techniques are in common use for precise measurements in high technology industries, such as aerospace, automotive, precision manufacturing and for the structural diagnostics of artwork. The phase map data generated by these instruments allows precise measurements of parameters such as displacement, strain and shape. The comparison of data from different measurement campaigns is useful for null testing components and for studying changes. However, the comparison of data with previous measurements is non-trivial due to the sensitivity of these techniques to alignment and to sample loading parameters. This paper addresses image and phase registration issues for holography and shearography. This manuscript describes 2D spatial co-registration to compensate for differences between the field of view between the measurements and a phase referencing to calculate the difference between the phase maps. These techniques are implemented after following a standardised measurement procedure. [less ▲]

Detailed reference viewed: 24 (3 ULiège)
Full Text
See detailRole of photorefractive holographic interferometry in Impact Assessment Procedure applied to movable cultural heritage
Thizy, Cédric ULiege; De Rauw, Dominique ULiege; Georges, Marc ULiege et al

in Proceedings of the International Symposium to Commemorate the 60th Anniversary of the Invention of Holography (2008, October)

Detailed reference viewed: 28 (6 ULiège)
Full Text
Peer Reviewed
See detailChirp-Z Transformed Based Interpolator Adaptation for Range Migration Correction
De Rauw, Dominique ULiege; Barbier, Christian ULiege

in Proc. EUSAR'08 Conference (2008)

Detailed reference viewed: 18 (2 ULiège)
Full Text
Peer Reviewed
See detailFirst Steps Towards Georeferencing of 3D VHR Optical and X-Band SAR Imagery
Belmonte, Antonella; De Rauw, Dominique ULiege; Barbier, Christian ULiege et al

in Proc. IGARSS'07 Symposium (2007)

Detailed reference viewed: 20 (2 ULiège)
Full Text
Peer Reviewed
See detailIce-dynamic conditions of Shirase Glacier, Antarctica, inferred from ERS SAR interferometry
Pattyn, Frank; De Rauw, Dominique ULiege

in Journal of Glaciology (2002), 48(163), 559-565

The surface velocity field of Shirase Glacier, a fast-flowing East Antarctic outlet glacier, is determined from ERS synthetic aperture radar (SAR) images by means of speckle tracking using phase ... [more ▼]

The surface velocity field of Shirase Glacier, a fast-flowing East Antarctic outlet glacier, is determined from ERS synthetic aperture radar (SAR) images by means of speckle tracking using phase correlation, a technique which matches small image kernels of two complex SAR images by maximization of the local coherence. Velocity estimates are used to calculate surface strain rates, which are then used to calculate the large-scale, vertically integrated force balance and to determine the major stress components resisting the driving stress. For the whole glacier system, the driving stress is largely balanced by the basal drag, but with contributions from lateral drag up to 15% of the driving stress at the grounding line. Longitudinal stress gradients have only local importance to the balance of forces, limited to an area of a few square kilometers near the grounding line, where they resist the driving stress. In the grounded part of the glacier, >90% of the total ice velocity is due to basal sliding. Comparison with a balance-flux distribution of the Antarctic ice sheet suggests that the glacier in the downstream part of the Shirase drainage basin is close to equilibrium, showing a slight negative imbalance. [less ▲]

Detailed reference viewed: 35 (1 ULiège)
Peer Reviewed
See detailInSAR Coherence for Crop Parameter Monitoring
Blaes, Xavier; Defourny, Pierre; De Rauw, Dominique ULiege et al

in ESA (Ed.) Proc. FRINGE'99 Symposium (1999)

Detailed reference viewed: 31 (3 ULiège)
Peer Reviewed
See detailCartography of Microclimatic Zones Using InSAR DTM
Closson, Damien; Cornet, Yves ULiege; Ozer, André ULiege et al

in ESA (Ed.) Proc. FRINGE'99 Symposium (1999)

Detailed reference viewed: 28 (2 ULiège)
Peer Reviewed
See detailQuality Assessment of InSAR Topographic Mapping : The Example of Belgium
De Rauw, Dominique ULiege; Barbier, Christian ULiege

in SPIE (Ed.) Proc. SPIE (1998)

Detailed reference viewed: 25 (2 ULiège)