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Ship Detection in SAR Image Based on the Alpha-stable Distribution
State Key Laboratory of Information Engineering in Survey, Mapping and Remote Sensing (LIESMARS), Wuhan University, Wuhan, Hubei 430079, P. R. China
NOAA Science Center, WWBG, Room 102, 5200 Auth Road, Camp Springs, MD 20746, U.S.A.
* Author to whom correspondence should be addressed.
Received: 19 June 2008; in revised form: 18 July 2008 / Accepted: 19 July 2008 / Published: 22 August 2008
Abstract: This paper describes an improved Constant False Alarm Rate (CFAR) ship detection algorithm in spaceborne synthetic aperture radar (SAR) image based on Alphastable distribution model. Typically, the CFAR algorithm uses the Gaussian distribution model to describe statistical characteristics of a SAR image background clutter. However, the Gaussian distribution is only valid for multilook SAR images when several radar looks are averaged. As sea clutter in SAR images shows spiky or heavy-tailed characteristics, the Gaussian distribution often fails to describe background sea clutter. In this study, we replace the Gaussian distribution with the Alpha-stable distribution, which is widely used in impulsive or spiky signal processing, to describe the background sea clutter in SAR images. In our proposed algorithm, an initial step for detecting possible ship targets is employed. Then, similar to the typical two-parameter CFAR algorithm, a local process is applied to the pixel identified as possible target. A RADARSAT-1 image is used to validate this Alpha-stable distribution based algorithm. Meanwhile, known ship location data during the time of RADARSAT-1 SAR image acquisition is used to validate ship detection results. Validation results show improvements of the new CFAR algorithm based on the Alpha-stable distribution over the CFAR algorithm based on the Gaussian distribution.
Keywords: Alpha-stable distribution; ship detection; Synthetic Aperture Radar; Constant False Alarm Rate (CFAR).
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MDPI and ACS Style
Wang, C.; Liao, M.; Li, X. Ship Detection in SAR Image Based on the Alpha-stable Distribution. Sensors 2008, 8, 4948-4960.
Wang C, Liao M, Li X. Ship Detection in SAR Image Based on the Alpha-stable Distribution. Sensors. 2008; 8(8):4948-4960.
Wang, Changcheng; Liao, Mingsheng; Li, Xiaofeng. 2008. "Ship Detection in SAR Image Based on the Alpha-stable Distribution." Sensors 8, no. 8: 4948-4960.