Michael Denbina

On the Reconstruction of Quad-Pol SAR Data From Compact Polarimetry Data For Ocean Target Detection

Circular-transmit/linear-receive compact polarimetry synthetic aperture radar systems combine coherent dual polarization with wide-swath imaging. The polarization information in these data may be represented as a Stokes vector, or one can reconstruct several quadpolarized covariance elements. Two reconstruction algorithms have been published in the literature: one by Souyris and a refined algorithm by Nord We investigated the application of these two algorithms for reconstructing ocean clutter for the purpose of detecting targets. We tested the assumptions underlying these algorithms and found that they were not valid for ocean scenes. We present a simple empirical reconstruction model whose reconstruction and target detection performance is superior to the two published algorithms.

On the Use of Simulated Airborne Compact Polarimetric SAR for Characterizing Oil–Water Mixing of the Deepwater Horizon Oil Spill

Compact polarimetry (CP) synthetic aperture radar (SAR) is a form of coherent dual-pol SAR that has been shown to have great potential for maritime surveillance applications such as ship and ice detection. In this paper, we demonstrate the potential of CP data for oil spill characterization. As the availability of CP data is limited at this time, we simulate CP image data from UAVSAR L-Band quad-polarized images. We reconstruct quad-pol SAR data (termed pseudo-quad) from these simulated CP SAR data, and calculate an oil-water mixing index, termed Mdex. We show that the differences between the pseudo-quad and quad-pol Mdex maps are negligible. This contributes to the case that CP SAR has great potential for multiple applications in maritime surveillance.

3D topography and forest recovery from an L-BAND single-pass airborne PolInSAR system

Polarimetric InSAR (PolInSAR) using repeat-pass L-Band has generated interest in recent years because of its potential for extraction of forest height and of bare-earth topography beneath the canopy. However temporal de-correlation remains a problem. In previous papers a single-pass system has been demonstrated which removes the temporal issue. In this paper we extend the single-pass PolInSAR work previously described and show results for forests in which tree height maps and corresponding DTMs have been generated and compared to lidar truth.

Iceberg Detection Using Simulated Dual-Polarized Radarsat Constellation Data

Abstract Iceberg monitoring is an important application of synthetic aperture radar (SAR), and is one of the stated objectives of the Radarsat Constellation, the next generation of Canada’s Radarsat satellites. In this paper, we simulate Radarsat Constellation data in a number of different imaging modes, using Radarsat-2 single-look complex data covering a study area in the Labrador Sea. We test the iceberg detection performance of both linear dual-pol data as well as compact polarimetry, a novel SAR architecture that transmits circular polarization rather than the traditional horizontal or vertical polarizations. We use the likelihood ratio test method to calculate a decision variable image for each of a number of different dual-pol and compact configurations, then analyze the detection performance using 25 validated iceberg locations spread across 12 different scenes. We found that compared to the linear data, the compact data missed fewer targets, and detected a greater number of pixels of detected targets, for most of the incidence angles and imaging modes tested. Compact polarimetry seems to be a promising choice for iceberg detection applications. Résumé La détection des icebergs est une application importante du radar à synthèse d’ouverture (RSO) et est un des objectifs déclarés de la Constellation RADARSAT, la prochaine génération de satellites RADARSAT du Canada. Dans cet article, nous simulons les données de la Constellation RADARSAT dans différents modes d’imagerie en utilisant des données singulières complexes de RADARSAT-2 couvrant une zone d’étude dans la mer du Labrador. Nous testons les performances de détection des icebergs des données linéaires en polarisation double ainsi que la polarimétrie compacte, une nouvelle architecture RSO qui transmet en polarisation circulaire plutôt qu’en polarisations horizontales ou verticales traditionnelles. Nous utilisons la méthode du test du rapport des vraisemblances pour calculer des images d’une variable de décision pour plusieurs configurations différentes en polarisation double et compacte, puis nous analysons les performances de détection en utilisant 25 positions d’iceberg validées réparties sur 12 scènes différentes. Nous avons constaté que, par rapport aux données linéaires, les données compactes ont manqué moins de cibles, et ont détecté un plus grand nombre de pixels sur les cibles détectées, pour la plupart des angles d’incidence et modes d’imagerie testés. La polarimétrie compacte semble être un choix prometteur pour des applications de détection d’iceberg.

On the Detection and Discrimination of Ships and Icebergs Using Simulated Dual-Polarized RADARSAT Constellation Data

Abstract. Maritime surveillance is an important application of synthetic aperture radar and is one of the objectives of the RADARSAT Constellation, the next generation of Canadas RADARSAT satellites. The RADARSAT Constellation will be able to collect both circular transmit, linear receive (CTLR) compact polarimetric data and linear dual-polarization data in a variety of wide swath imaging modes. In this article, we focus on the medium-resolution and low-resolution modes in order to assess the capability of the RADARSAT Constellation to both detect ships and icebergs in ocean imagery and then to discriminate between them after detection is performed. We first performed target detection, using a method whereby the false alarm rate was adjusted from pixel to pixel based on the properties of the received polarization ellipse. We then attempted to discriminate between the detected ship and iceberg targets using a support vector machine classifier. Measuring the discrimination accuracy using stratified 10-fold cross-validation, we found that the CTLR data had an accuracy of 99.3% for the medium-resolution imaging mode compared to 96.5% for the HH-HV dual-polarization. Further work is necessary using a wider variety of data, but RADARSAT Constellation data seem to have strong potential for ocean target detection and discrimination. Résumé. La surveillance maritime est une application importante du radar à synthèse d’ouverture, et elle représente un des objectifs de la Constellation RADARSAT, qui est la prochaine génération de satellites canadiens RADARSAT. La Constellation RADARSAT sera en mesure de recueillir à la fois des données de polarimétrie compacte CTLR (transmission circulaire, réception linéaire) et des données linéaires en polarisation double dans une variété de modes d’imagerie avec une large fauchée. Dans cet article, nous nous concentrons sur les modes à basse et moyenne résolution afin d’évaluer la capacité de la Constellation RADARSAT pour la détection à la fois des navires et des icebergs dans l’imagerie de l’océan, puis de les discriminer après que la détection est effectuée. Nous avons d’abord procédé à la détection de cibles, en utilisant un procédé par lequel le taux de fausses alarmes a été ajusté de pixel à pixel sur la base des propriétés de l’ellipse de polarisation reçue. Nous avons ensuite tenté de distinguer les navires des icebergs entre les cibles détectées, en utilisant un classificateur de machine à vecteurs de support. En mesurant la précision de la discrimination en utilisant une validation stratifiée croisée à 10 plis, nous avons constaté que les données CTLR avaient une précision de 99,3 % pour le mode de résolution d’imagerie moyenne, par rapport à 96,5 % pour la polarisation double HH-HV. Des travaux supplémentaires sont nécessaires en utilisant une plus grande variété de données, mais les données de la Constellation RADARSAT semblent avoir un fort potentiel pour la détection et la discrimination des cibles océaniques.

Iceberg detection using analysis of the received polarization ellipse in compact polarimetry

Iceberg monitoring, as well as maritime surveillance in general, is an important application of synthetic aperture radar (SAR). Compact polarimetry offers the potential for improved detection performance compared to traditional linear dualpol SAR. The Radarsat Constellation, Canadas next Radarsat satellite, will collect compact polarimetric data in a variety of imaging modes. Using Radarsat-2 fine-quad mode data we have simulated Radarsat Constellation data and calculated the detection performance of the compact data using 25 validated iceberg locations in the Labrador Sea. We also propose a method through which the shape and orientation of the received polarization ellipse in the compact polarimetric data can be used to improve the detection performance.