A New Detection Algorithm for Coherent Scatterers in SAR Data

Sanjuan-Ferrer, Maria J.; Hajnsek, Irena; Papathanassiou, Konstantinos; Moreira, Alberto

doi:10.1109/tgrs.2015.2438173

Cited by 31 publications

(27 citation statements)

References 31 publications

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“…Stable point-like scatterers which dominate their resolution-cell are often referred to as coherent scatterers (Sanjuan-Ferrer et al 2015). Different methods have been presented for the detection of coherent scatterers in a single high-resolution SAR image, such as the ones introduced by Schneider et al (2006) and Giacovazzo et al (2008).…”

Section: Detection Of Coherent Scatterers In Single Sar Imagesmentioning

confidence: 99%

“…The sub-looks can be computed in range (i.e., different frequency bands) azimuth (i.e., different sub-apertures or Doppler frequencies). Sanjuan-Ferrer et al (2015) have shown a comparison between four different methods. For its simplicity and good performance, we will apply the phase variance approach introduced by Schneider and Papathanassiou (2009).…”

Section: Detection Of Coherent Scatterers In Single Sar Imagesmentioning

confidence: 99%

See 1 more Smart Citation

Using Coherent Scatterers in Time Series of High Resolution Sar Images for the Monitoring of Construction Activity

Lopez

Stilla

2019

ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci.

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<p><strong>Abstract.</strong> In this paper, we present a method for detecting and quantifying changes due to construction activity in time series of high resolution SAR images. We propose to detect these changes by the appearance or disappearance of a large number of coherent scatterers, rather than by looking at changes in SAR amplitude or coherence. These coherent scatterers, which appear mainly in buildings and other man-made structures, will be detected in each individual image by analysing their stability across multiple frequency sub-bands. This implies that long time series are not required, unlike for other similar approaches based in persistent scatterer interferometry, and that this approach can be applied for the monitoring of fast changing areas such as temporary settlements. The presented approach will be applied for monitoring the construction activity taking place during the preparations for two large festivals in Munich, Germany.</p>

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Section: Detection Of Coherent Scatterers In Single Sar Imagesmentioning

confidence: 99%

Section: Detection Of Coherent Scatterers In Single Sar Imagesmentioning

confidence: 99%

Using Coherent Scatterers in Time Series of High Resolution Sar Images for the Monitoring of Construction Activity

Lopez

Stilla

2019

ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci.

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“…On the other hand, standard image pre-processors can be considered linear and phase preserving to a large extent, implying that the whole information in the frequency domain is preserved after focusing, apart from the windowing operation necessary to reduce sidelobes. Accordingly, the sub-look images can be generated directly from focused images by calculating the Fourier transform of the image (in the range or azimuth), removing the windowing and selecting a portion of the full spectrum, i.e., by multiplying such a spectrum by a rectangular weighting function and computing its inverse Fourier transform [4,5]. A diagram summarizing the main steps of the sub-looking process in the range direction is depicted in Figure 1.…”

Section: Spectral Analysis Of Sar Datamentioning

confidence: 99%

“…Two recently proposed algorithms aimed at detecting coherent scatterers for interferometry and tracking methodologies are tested for the first time for ship detection. These are the generalized likelihood ratio test (GLRT) of sub-look images [4,5] and the sub-look entropy [6]. 2.…”

Section: Introductionmentioning

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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“…In 2010, Ouchi et al 16 proposed a ship detection algorithm based on the cross-correlation between different sublook images. In 2015, Marino et al 17 tested the performance of a series of spectra-based ship detection algorithms, including the generalized likelihood ratio test method, [18][19][20] sublook entropy method, 21 sublook coherence method, 1,22 and sublook cross-correlation method, 23,24 through different space-borne SAR data. All of the aforementioned algorithms are based on the assumption that a ship can be considered as a coherent scatterer so that it possesses higher degree of coherence than the uncorrelated sea clutter in different sublook images.…”

Section: Introductionmentioning

confidence: 99%

Local region power spectrum-based unfocused ship detection method in synthetic aperture radar images

Wei

Wang

Chong

2018

J. Appl. Rem. Sens.

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, "Local region power spectrum-based unfocused ship detection method in synthetic aperture radar images," J. Appl. Remote Sens. 12(1), 016026 (2018), doi: 10.1117/1.JRS.12.016026. Abstract. Ships on synthetic aperture radar (SAR) images will be severely defocused and their energy will disperse into numerous resolution cells under long SAR integration time. Therefore, the image intensity of ships is weak and sometimes even overwhelmed by sea clutter on SAR image. Consequently, it is hard to detect the ships from SAR intensity images. A ship detection method based on local region power spectrum of SAR complex image is proposed. Although the energies of the ships are dispersed on SAR intensity images, their spectral energies are rather concentrated or will cause the power spectra of local areas of SAR images to deviate from that of sea surface background. Therefore, the key idea of the proposed method is to detect ships via the power spectra distortion of local areas of SAR images. The local region power spectrum of a moving target on SAR image is analyzed and the way to obtain the detection threshold through the probability density function (pdf) of the power spectrum is illustrated. Numerical P-and L-band airborne SAR ocean data are utilized and the detection results are also illustrated. Results show that the proposed method can well detect the unfocused ships, with a detection rate of 93.6% and a false-alarm rate of 8.6%. Moreover, by comparing with some other algorithms, it indicates that the proposed method performs better under long SAR integration time. Finally, the applicability of the proposed method and the way of parameters selection are also discussed. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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A New Detection Algorithm for Coherent Scatterers in SAR Data

Cited by 31 publications

References 31 publications

Using Coherent Scatterers in Time Series of High Resolution Sar Images for the Monitoring of Construction Activity

Using Coherent Scatterers in Time Series of High Resolution Sar Images for the Monitoring of Construction Activity

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

Local region power spectrum-based unfocused ship detection method in synthetic aperture radar images

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