منابع مشابه
Interferometric Synthetic Aperture Sonar
Interferometric Synthetic Aperture Sonar (ISAS) offers the possibility of high resolution, three-dimensional images of objects on the ocean floor. The height of objects is identified from the phase difference between two synthetic aperture images of the object obtained using two receivers separated by a short distance. A central problem is the need to unwrap the phase difference in the presence...
متن کاملEffect of Multipath on Synthetic Aperture Sonar
Abstract The performance of real or synthetic aperture sonar (SAS) in shallow waters is degraded by multipath, which leads to ghost targets and reduced image contrast. This loss of image contrast fills in acoustic shadows and is therefore an important limitation for high resolution SAS applications such as minehunting, where target recognition exploits the shape and size of the shadow in additi...
متن کاملIncoherent Synthetic Aperture Sonar Processing
This chapter investigates the incoherent approach applied in synthetic aperture sonar processing. The details of implementation are shown, and the technical properties of this technique are presented. Simulations are presented along the way for purposes of illustrations and comparisons. Discussions of the potential and limitation of this approach are made. All the simulations and analytical inv...
متن کاملSpeckle Reduction of Synthetic Aperture Sonar Images
Multi-look processing is a well known technique for reducing speckle in coherent imagery. This paper investigates the use of multi-look processing in range (frequency-compounding) on SAS images. The coherence between sub-images produced by frequency compounding is determined and a coherence model proposed. This is used to calculate the level of speckle reduction for a given number of looks and ...
متن کاملCircular Synthetic Aperture Sonar without a Beacon
Collection of synthetic aperture sonar (SAS) data along a circular track and forming a circular SAS (CSAS) image has several benefits over traditional stripmap SAS: the area of interest is observed from all aspect angles giving a better perception; the resolution in the image increases and shadow zones are avoided. Navigation requirements however, become even more stringent than for rectilinear...
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ژورنال
عنوان ژورنال: The Journal of the Acoustical Society of America
سال: 1988
ISSN: 0001-4966
DOI: 10.1121/1.2026348