基于分块相位梯度算法的多舰船尾迹自动识别
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摘要
提出一种基于分块相位梯度算法(PGA)的多舰船尾迹合成孔径雷达(SAR)图像自动识别方法。首先在多结构形态学滤波和自适应阈值(OTSU)分割的基础上,利用分块PGA算法消除运动舰船的位置偏移和像元模糊,还原舰船实际信息;利用改进的局部Hough变换对分块图像进行检测和识别,根据识别出的尾迹坐标和角度反演运动舰船位置和航向信息。检测结果表明,该算法可准确检测SAR图像中舰船的实际位置和航向,识别准确度高,抗干扰性强。
A Phase Gradient Algorithm(PGA) based algorithm for the automatic recognition of multiple ship wakes in Synthetic Aperture Radar(SAR) image is presented. Firstly, the center point of each ship image is extracted by using a combination algorithm of multiple-structure morphology filtering, the OTSU automatic segmentation and the clustering method. Then, the whole image is divided into sub-images which are chosen to be a square of appropriate size and the centers of sub-images are the detected points. As moving ships in SAR image always result in residual chirps in the azimuthally processed signals, the block-wise PGA is utilized to compensate the position offset and defocusing effect in each sub-image. Finally, an improved local Hough transform is proposed to detect the ship wake based on an inverse analysis of the detected wake's coordinate and angle, and the locations and the trajectories of each moving ship are obtained. The examples demonstrate that this algorithm can accurately recognize and restore the ships' actual trajectories and locations with high detectability and low false detection rate.
A Phase Gradient Algorithm(PGA) based algorithm for the automatic recognition of multiple ship wakes in Synthetic Aperture Radar(SAR) image is presented. Firstly, the center point of each ship image is extracted by using a combination algorithm of multiple-structure morphology filtering, the OTSU automatic segmentation and the clustering method. Then, the whole image is divided into sub-images which are chosen to be a square of appropriate size and the centers of sub-images are the detected points. As moving ships in SAR image always result in residual chirps in the azimuthally processed signals, the block-wise PGA is utilized to compensate the position offset and defocusing effect in each sub-image. Finally, an improved local Hough transform is proposed to detect the ship wake based on an inverse analysis of the detected wake's coordinate and angle, and the locations and the trajectories of each moving ship are obtained. The examples demonstrate that this algorithm can accurately recognize and restore the ships' actual trajectories and locations with high detectability and low false detection rate.
引文
[1]COPELANG A C,RAVICHANDRAN G,TRIVEDI M M.Localized Radon transform-based detection of ship wakes in SARimages[J].IEEE Transactions on Geoscience and Remote Sensing,1995,33(1):35-45.
[2]王世庆,金亚秋.SAR图像船行尾迹检测的Radon变换和形态学图像处理技术[J].遥感学报,2001,4(4):289-294.(WANG Shiqing,JIN Yaqiu.Ship wake detection in SAR images based on Radon transformation and morphologic image processing[J].Journal of Remote Sensing,2001,4(4):289-294.)
[3]种劲松,朱敏慧.基于归一化灰度Hough变换的SAR图像舰船尾迹检测算法[J].中国图形图像学报,2004,9(2):146-150.(CHONG Jingsong,ZHU Minhui.Ship wake detection algorithm in SAR image based on normalized grey level Hough transform[J].Journal of Image and Graphics,2004,9(2):146-150.)
[4]王连亮,陈怀新.基于递归修正Hough变换域的舰船多尾迹检测方法[J].系统工程与电子技术,2009,31(4):834-837.(WANG Lianliang,CHEN Huaixin.Multi-ship detection method based on recursive modified Hough transform field[J].Systems Engineering and Electronics,2009,31(4):834-837.)
[5]WACKERMAN C C,FRIEDMAN K S,PICHEL W G.Automatic detection of ships in RADARSAT-1 SAR imagery[J].Canadian Journal of Remote Sensing,2001,27(23):568-577.
[6]罗强,罗莉,任庆利.一种基于小波变换的卫星SAR海洋图像舰船目标检测方法[J].兵工学报,2002,23(23):500-503.(LUO Qiang,LUO Li,REN Qingli.Method of ship detection in oceanic SAR image based on wavelet transform[J].Acta Armamentarii,2002,23(23):500-503.)
[7]牛朝阳,马德宝,李武皋.基于联合PWF-2p CFAR算法的Envisat/ASAR双极化数据舰船检测方法研究[J].信息工程大学学报,2008,9(3):319-322.(NIU Chaoyang,MA Debao,LI Wugao.Ship detection based on the combined PWF-2p CFARalgorithm using envisat/ASAR dual polarization data[J].Journal of Information Engineering University,2008,9(3):319-322.)
[8]张东晓,何四华,杨绍清.一种多尺度分形的舰船目标检测方法[J].激光与红外,2009,39(3):315-318.(ZHANG Dongxiao,HE Sihua,YANG Shaoqing.Ship target detection method based on multi-scale fractal feature[J].Laser and Infrared,2009,39(3):315-318.)
[9]AI Jiaqiu,QI Xiangyang,YU Weidong,et al.A novel ship wake CFAR detection algorithm based on SCR enhancement and normalized Hough transform[J].IEEE Geoscience and Remote Sensing Letters,2011,8(4):681-685.
[10]张宏稷,杨健.基于非邻域结构似然函数的舰船检测方法[J].太赫兹科学与电子信息学报,2013,11(6):875-879.(ZHANG Hongji,YANG Jian.Non-local structure and likelihood function based ship detection[J].Journal of Terahertz Science and Electronic Information Technology,2013,11(6):875-879.)
[11]DENG Yuan,ZHANG Yunhua.Improved PGA algorithm based on adaptive range bins selection[J].Journal of Language Teaching and Research,2010,1(2):151-156.
[12]FARAJZADEH M,MAHMOODI A,ARVAN M R.Detection of small target based on morphological filters[C]//20th Iranian Conference on Electrical Engineering.Tehran,Irana:IEEE,2012:1097-1101.
[13]OTSU N.A threshold selection method from gray level histograms[J].IEEE Transactions on Systems Man and Cybernetics IEEE Transactions,1979,9(1):62-69.
[14]ZILMAN G,ZAPOLSKI A,MAROM M.On detectability of a ship's Kelvin wake in simulated SAR images of rough sea surface[J].IEEE Transactions on Geoscience and Remote Sensing,2015,53(2):609-619.
[15]倪崇,王岩飞,徐向辉.一种改进的SAR图像聚焦算法[J].测绘学报,2012,41(3):449-453.(NI Chong,WANG Yanfei,XU Xianghui.An improved autofocus algorithm for SAR images[J].Acta Geodaetica Sinica,2012,41(3):449-453.)
[16]QING Jiming,XU Haoyu,LIANG Xingdong,et al.An improved phase gradient autofocus algorithm used in real-time processing[J].Journal of Radars,2015,4(5):600-607.
[2]王世庆,金亚秋.SAR图像船行尾迹检测的Radon变换和形态学图像处理技术[J].遥感学报,2001,4(4):289-294.(WANG Shiqing,JIN Yaqiu.Ship wake detection in SAR images based on Radon transformation and morphologic image processing[J].Journal of Remote Sensing,2001,4(4):289-294.)
[3]种劲松,朱敏慧.基于归一化灰度Hough变换的SAR图像舰船尾迹检测算法[J].中国图形图像学报,2004,9(2):146-150.(CHONG Jingsong,ZHU Minhui.Ship wake detection algorithm in SAR image based on normalized grey level Hough transform[J].Journal of Image and Graphics,2004,9(2):146-150.)
[4]王连亮,陈怀新.基于递归修正Hough变换域的舰船多尾迹检测方法[J].系统工程与电子技术,2009,31(4):834-837.(WANG Lianliang,CHEN Huaixin.Multi-ship detection method based on recursive modified Hough transform field[J].Systems Engineering and Electronics,2009,31(4):834-837.)
[5]WACKERMAN C C,FRIEDMAN K S,PICHEL W G.Automatic detection of ships in RADARSAT-1 SAR imagery[J].Canadian Journal of Remote Sensing,2001,27(23):568-577.
[6]罗强,罗莉,任庆利.一种基于小波变换的卫星SAR海洋图像舰船目标检测方法[J].兵工学报,2002,23(23):500-503.(LUO Qiang,LUO Li,REN Qingli.Method of ship detection in oceanic SAR image based on wavelet transform[J].Acta Armamentarii,2002,23(23):500-503.)
[7]牛朝阳,马德宝,李武皋.基于联合PWF-2p CFAR算法的Envisat/ASAR双极化数据舰船检测方法研究[J].信息工程大学学报,2008,9(3):319-322.(NIU Chaoyang,MA Debao,LI Wugao.Ship detection based on the combined PWF-2p CFARalgorithm using envisat/ASAR dual polarization data[J].Journal of Information Engineering University,2008,9(3):319-322.)
[8]张东晓,何四华,杨绍清.一种多尺度分形的舰船目标检测方法[J].激光与红外,2009,39(3):315-318.(ZHANG Dongxiao,HE Sihua,YANG Shaoqing.Ship target detection method based on multi-scale fractal feature[J].Laser and Infrared,2009,39(3):315-318.)
[9]AI Jiaqiu,QI Xiangyang,YU Weidong,et al.A novel ship wake CFAR detection algorithm based on SCR enhancement and normalized Hough transform[J].IEEE Geoscience and Remote Sensing Letters,2011,8(4):681-685.
[10]张宏稷,杨健.基于非邻域结构似然函数的舰船检测方法[J].太赫兹科学与电子信息学报,2013,11(6):875-879.(ZHANG Hongji,YANG Jian.Non-local structure and likelihood function based ship detection[J].Journal of Terahertz Science and Electronic Information Technology,2013,11(6):875-879.)
[11]DENG Yuan,ZHANG Yunhua.Improved PGA algorithm based on adaptive range bins selection[J].Journal of Language Teaching and Research,2010,1(2):151-156.
[12]FARAJZADEH M,MAHMOODI A,ARVAN M R.Detection of small target based on morphological filters[C]//20th Iranian Conference on Electrical Engineering.Tehran,Irana:IEEE,2012:1097-1101.
[13]OTSU N.A threshold selection method from gray level histograms[J].IEEE Transactions on Systems Man and Cybernetics IEEE Transactions,1979,9(1):62-69.
[14]ZILMAN G,ZAPOLSKI A,MAROM M.On detectability of a ship's Kelvin wake in simulated SAR images of rough sea surface[J].IEEE Transactions on Geoscience and Remote Sensing,2015,53(2):609-619.
[15]倪崇,王岩飞,徐向辉.一种改进的SAR图像聚焦算法[J].测绘学报,2012,41(3):449-453.(NI Chong,WANG Yanfei,XU Xianghui.An improved autofocus algorithm for SAR images[J].Acta Geodaetica Sinica,2012,41(3):449-453.)
[16]QING Jiming,XU Haoyu,LIANG Xingdong,et al.An improved phase gradient autofocus algorithm used in real-time processing[J].Journal of Radars,2015,4(5):600-607.