Sidelobes Suppression and Strong Targets Extraction in Single Look Complex SAR Images with Several Applications

Abstract :

Synthetic aperture radar (SAR) images display very high dynamic ranges. Man-made structures (like buildings or power towers) produce echoes that are several orders of magni- tude stronger than echoes from diffusing areas (vegetated areas) or from smooth surfaces (e.g., roads). The impulse response of the SAR imaging system is, thus, clearly visible around the strongest targets: sidelobes spread over several pixels, masking the much weaker echoes from the background. To reduce the sidelobes of the impulse response, images are generally spectrally apodized, trad- ing resolution for a reduction of the sidelobes. This apodization procedure (global or shift-variant) introduces spatial correlations in the speckle-dominated areas that complicates the design of esti- mation methods. This paper describes strategies to cancel sidelobes around point-like targets while preserving the spatial resolution and the statistics of speckle-dominated areas. An irregular sam- pling grid is built to compensate the subpixel shifts and turn cardi- nal sines into discrete Diracs. A statistically grounded approach for point-like target extraction is also introduced, thereby providing a decomposition of a single look complex image into two compo- nents: a speckle-dominated image and the point-like targets. This decomposition can be exploited to produce images with improved quality (full resolution and suppressed sidelobes) suitable both for visual inspection and further processing (multitemporal analysis, despeckling, interferometry).

Document type :
Journal articles
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Submitted on : Friday, September 13, 2019 - 5:10:49 PM
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Rémy Abergel, L. Denis, Saïd Ladjal, Florence Tupin. Sidelobes Suppression and Strong Targets Extraction in Single Look Complex SAR Images with Several Applications. IEEE Journal of Selected Topics in Applied Observation and Remote Sensing, 2018, 11 (3), pp.759 - 776. ⟨hal-02287651⟩



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