Nonuniform azimuth image shift observed in the Radarsat images of ships in motion

Ouchi, Kazuo; Iehara, M.; Morimura, K.; Kumano, Shintaro; Takami, Isao

doi:10.1109/tgrs.2002.802478

Cited by 37 publications

(34 citation statements)

References 6 publications

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“…The former one is known when the turbulent wake direction is calculated, the azimuth direction w.r.t. the True North being included in ancillary data; whereas, ship velocity is estimated by state-of-the-art techniques of azimuth shift [11][12][13] and Kelvin pattern wavelength.…”

Section: Ship Heading and Velocitymentioning

confidence: 99%

“…In this ambit, ship wake detection not only has strong interest as the validation of ship presence, but also generates data useful for ship route estimation. In fact, if wake direction provides information about ship heading, methodologies have also been developed to derive ship velocity from additional wake-based information [11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

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Wake Component Detection in X-Band SAR Images for Ship Heading and Velocity Estimation

2016

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Abstract:A new algorithm for ship wake detection is developed with the aim of ship heading and velocity estimation. It exploits the Radon transform and utilizes merit indexes in the intensity domain to validate the detected linear features as real components of the ship wake. Finally, ship velocity is estimated by state-of-the-art techniques of azimuth shift and Kelvin arm wavelength. The algorithm is applied to 13 X-band SAR images from the TerraSAR-X and COSMO/SkyMed missions with different polarization and incidence angles. Results show that the vast majority of wake features are correctly detected and validated also in critical situations, i.e., when multiple wake appearances or dark areas not related to wake features are imaged. The ship route estimations are validated with truth-at-sea in seven cases. Finally, it is also verified that the algorithm does not detect wakes in the surroundings of 10 ships without wake appearances.

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Section: Ship Heading and Velocitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wake Component Detection in X-Band SAR Images for Ship Heading and Velocity Estimation

2016

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“…In the framework of ship detection, smearing leads to not having a point target anymore, and therefore, a coherent detector may fail. As a final remark, the Doppler analysis may be performed keeping in mind the possibility of miss detections due to vessel movements [37,38].…”

Section: Spectral Analysis Of Sar Datamentioning

confidence: 99%

Ship Detection with Spectral Analysis of Synthetic Aperture Radar: A Comparison of New and Well-Known Algorithms

et al. 2015

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The surveillance of maritime areas with remote sensing is vital for security reasons, as well as for the protection of the environment. Satellite-borne synthetic aperture radar (SAR) offers large-scale surveillance, which is not reliant on solar illumination and is rather independent of weather conditions. The main feature of vessels in SAR images is a higher backscattering compared to the sea background. This peculiarity has led to the development of several ship detectors focused on identifying anomalies in the intensity of SAR images. More recently, different approaches relying on the information kept in the spectrum of a single-look complex (SLC) SAR image were proposed. This paper is focused on two main issues. Firstly, two recently developed sub-look detectors are applied for the first time to ship detection. Secondly, new and well-known ship detection algorithms are compared in order to understand which has the best performance under certain circumstances and if the sub-look analysis improves ship detection. The comparison is done on real SAR data exploiting diversity in frequency and polarization. Specifically, the employed data consist of six RADARSAT-2 fine quad-polacquisitions over the North Sea, five TerraSAR-X HH/VV dual-polarimetric data-takes, also over the North Sea, and one ALOS-PALSAR quad-polarimetric dataset over Tokyo Bay. Simultaneously to the Remote Sens. 2015, 7 5417 SAR images, validation data were collected, which include the automatic identification system (AIS) position of ships and wind speeds. The results of the analysis show that the performance of the different sub-look algorithms considered here is strongly dependent on polarization, frequency and resolution. Interestingly, these sub-look detectors are able to outperform the classical SAR intensity detector when the sea state is particularly high, leading to a strong clutter contribution. It was also observed that there are situations where the performance improvement thanks to the sub-look analysis is not so noticeable.

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“…The results have shown that CTD present some limitations for vessel classification under adverse environmental conditions and limited image resolutions. Important restrictions are that they do not retrieve quantitative estimates of geometrical features and the results can be affected by the azimuth distortions induced by the sea state [11], [18]. In this context, this paper tries to expand the information derived from CTD with single-pass interferometry.…”

Section: Vessel Scattering Studymentioning

confidence: 99%

“…The selection of these guide scatters is performed according to two main considerations, namely, as follows: 1) the relative distance and height among PePS should be the maximum possible and 2) they should be placed in clean scattering areas, i.e., areas where no other scattering centers could interfere them. As commented later, such considerations are very useful to relax resolution requirements and to reduce the influence of some known distortions due to the sea environment [11], [18]. For the vessels presented in Fig.…”

Section: A Classification Patternsmentioning

confidence: 99%

Single-Pass Polarimetric SAR Interferometry for Vessel Classification

Margarit

Mallorquí

Fábregas

2007

IEEE Trans. Geosci. Remote Sensing

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Abstract-This paper presents a novel method for vessel classification based on single-pass polarimetric synthetic aperture radar (SAR) interferometry. It has been developed according to recent ship scattering studies that show that the polarimetric response of many types of vessels can be described by trihedral-and dihedral-like mechanisms. The adopted methodology is quite simple. The input interferometric data are decomposed in terms of the Pauli basis, and hence, one height image is derived for each simple mechanism. Then, the local maxima of these images are isolated, and a 3-D map of scatters is generated. The correlation of this map with the scattering distribution expected for a set of reference ships provides the final classification decision. The performance of the proposed method has been tested with the orbital SAR simulator developed at Universitat Politècnica de Catalunya. Different vessel models have been processed with a sensor configuration similar to the incoming TanDEM-X system. The analysis of diverse vessel bearings, vessel speeds, and sea states shows that the map of scatters matches reasonably the geometry of ships allowing a correct identification even for adverse environmental conditions. Index Terms-Coherent target decomposition (CTD), polarimetric synthetic aperture radar interferometry (PolInSAR), vessel classification.

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Nonuniform azimuth image shift observed in the Radarsat images of ships in motion

Cited by 37 publications

References 6 publications

Wake Component Detection in X-Band SAR Images for Ship Heading and Velocity Estimation

Wake Component Detection in X-Band SAR Images for Ship Heading and Velocity Estimation

Ship Detection with Spectral Analysis of Synthetic Aperture Radar: A Comparison of New and Well-Known Algorithms

Single-Pass Polarimetric SAR Interferometry for Vessel Classification

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