Change detection in SAR time-series based on the coefficient of variation

This paper discusses change detection in SAR time-series. Firstly, several statistical properties of the coefficient of variation highlight its pertinence for change detection. Then several criteria are proposed. The coefficient of variation is suggested to detect any kind of change. Then other criteria based on ratios of coefficients of variations are proposed to detect long events such as construction test sites, or point-event such as vehicles. These detection methods are evaluated first on theoretical statistical simulations to determine the scenarios where they can deliver the best results. Then detection performance is assessed on real data for different types of scenes and sensors (Sentinel-1, UAVSAR). In particular, a quantitative evaluation is performed with a comparison of our solutions with state-of-the-art methods

Apport de la Polarimétrie à l'interférometrie radar pour l'estimation de hauteurs de cibles et de paramètres de forêt

A recent development of radar polarimetry consists in its association with interferometry. Polarimetric analysis makes it possible to consider different scattering mechanisms within a given resolution cell, whereas interferometric techniques allow for a topographical characterization of the scattering contributions. Their combined application yields notable results for improving digital elevation models (DEM) or for forest parameters estimation thanks to coherent scattering models. The potential of several theoretical developments is tested using indoor measurements and real SAR data provided by the airborne system RAMSES in ONERA at P-, L- and X-band.Un développement récent de la polarimétrie en imagerie radar consiste à l'associer à l'interférométrie. L'analyse polarimétrique permet de comprendre les mécanismes électromagnétiques qui ont lieu au sein d'une cellule de résolution, tandis que l'interférométrie permet de calculer la hauteur du "centre de phase" de cette même cellule. L'utilisation conjointe de ces deux techniques permet d'envisager des bénéfices aussi divers que l'amélioration de la qualité des cartes d'élévations pour une zone urbaine, ou l'estimation des paramètres descriptifs d'une forêt à partir de modèles de diffusion. Les principaux outils théoriques proposés sont validés par des résultats de mesures en chambre anéchoïque et des images SAR du système aéroporté RAMSES de l'ONERA en bandes X, P et L

Apport de la polarimétrie à l'interférométrie radar pour l'estimation des hauteurs de cibles et paramètres de forêt

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Investigating about attenuation,scattering phase center and total height using simulated interferometric SAR images of forested areas

International audienceThe objective of this paper is to examine the link between the attenuation coefficients and the interferometric phase center heights, for several frequencies from P- to L-band, and to study the extent to which it depends on the canopy architecture and description. This paper relies on the use of a coherent and full polarimetric scattering model, which simulates the fields backscattered by a forested area. In the first part, we study the behavior with a frequency of the interferometric phase center heights, and in the second part, we focus on the attenuation coefficients. Then, we compare the behaviors of these two quantities, and we propose to empirically derive a relation between these two quantities and the mean forest height. Finally, we investigate if a change in the initial forest or radar configuration has an impact on the determination of this relation

Bistatic scattering by forested areas at low frequencies: simulation and indoor measurements

International audienc

Change Detection Based on the Coefficient of Variation in SAR Time-Series of Urban Areas

This paper discusses change detection in SAR time-series. First, several statistical properties of the coefficient of variation highlight its pertinence for change detection. Subsequently, several criteria are proposed. The coefficient of variation is suggested to detect any kind of change. Furthermore, several criteria that are based on ratios of coefficients of variations are proposed to detect long events, such as construction test sites, or point-event, such as vehicles. These detection methods are first evaluated on theoretical statistical simulations to determine the scenarios where they can deliver the best results. The simulations demonstrate the greater sensitivity of the coefficient of variation to speckle mixtures, as in the case of agricultural plots. Conversely, they also demonstrate the greater specificity of the other criteria for the cases addressed: very short event or longer-term changes. Subsequently, detection performance is assessed on real data for different types of scenes and sensors (Sentinel-1, UAVSAR). In particular, a quantitative evaluation is performed with a comparison of our solutions with baseline methods. The proposed criteria achieve the best performance, with reduced computational complexity. On Sentinel-1 images containing mainly construction test sites, our best criterion reaches a probability of change detection of 90% for a false alarm rate that is equal to 5%. On UAVSAR images containing boats, the criteria proposed for short events achieve a probability of detection equal to 90% of all pixels belonging to the boats, for a false alarm rate that is equal to 2%

First polarimetric validation and results on the bistatic scattering by a set of cylinders using a forest scattering model

International audienc

Change detection in SAR time-series based on the coefficient of variation

This paper discusses change detection in SAR time-series. Firstly, several statistical properties of the coefficient of variation highlight its pertinence for change detection. Then several criteria are proposed. The coefficient of variation is suggested to detect any kind of change. Then other criteria based on ratios of coefficients of variations are proposed to detect long events such as construction test sites, or point-event such as vehicles. These detection methods are evaluated first on theoretical statistical simulations to determine the scenarios where they can deliver the best results. Then detection performance is assessed on real data for different types of scenes and sensors (Sentinel-1, UAVSAR). In particular, a quantitative evaluation is performed with a comparison of our solutions with state-of-the-art methods