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dc.contributor.advisorAnfinsen, Stian Normann
dc.contributor.advisorGjøvik, Lars-Petter
dc.contributor.advisorOlsen, Ole Morten
dc.contributor.authorNylehn, Tina Eliassen
dc.description.abstractSeveral ship detection algorithms have been developed over the years, where some of the most commonly used are the constant false alarm rate (CFAR) algorithms. There are challenges to the existing algorithms, both when it comes to processing time and difficult scene situations, such as heterogeneous ocean clutter and multiple targets. Existing algorithms that are equipped to handle situations where clutter edges and multiple targets are present, will require significantly increased processing time. The goal of this thesis is to present a new fast method to estimate the underlying radar reflectivity from a speckled SAR image. The aim is to recover the mean intensity, which is a key parameter in statistical models of SAR intensity measurements over ocean. The estimation of the mean intensity should be fast and robust, in the sense that it handles heterogeneous clutter edges and the presence of multiple targets. The result from the presented algorithm is meant to be an input parameter for current ship detectors. The steps of the intended algorithm is to take advantage of a nonuniform FFT (NFFT) to truncated SAR data, which will result in frequencies on a regular grid. Next, a lowpass filter will be applied in order to suppress speckle present in the image. Finally, an inverse transformation will be utilized and an estimated mean intensity can be recovered. Thus, a threshold can be determined based on this mean value. Because the NFFT did not provide the desired results, it was not possible to present a complete algorithm.en_US
dc.publisherUiT The Arctic University of Norwayen_US
dc.publisherUiT Norges arktiske universiteten_US
dc.rights.holderCopyright 2015 The Author(s)
dc.rightsAttribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0)en_US
dc.subjectVDP::Mathematics and natural science: 400::Physics: 430en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Fysikk: 430en_US
dc.titleFast estimation of ocean background reflectivity in synthetic aperture radar imagesen_US
dc.typeMaster thesisen_US

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Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0)
Except where otherwise noted, this item's license is described as Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0)