摘要
在极化合成孔径雷达(PolSAR)图像杂波服从K分布下,已有的基于多视极化白化滤波器(MPWF)的恒虚警(CFAR)检测方法不适用于等效视数为非整数情形.针对此问题,提出了一种具有解析虚警概率表达式的CFAR检测方法.在乘积模型下引入Gamma分布纹理变量后,对MPWF检测量的概率密度函数(PDF)积分得到其累积分布函数(CDF),进而得到虚警概率关于检测门限的解析形式.仿真实验结果表明新方法良好的虚警拟合效果,此外在目标杂波比(TCR)较大时,新方法检测概率更高,反之,检测概率低于已有方法.需说明的是,目前K分布下多视极化匹配滤波(MPMF)检测方法的虚警概率表达式存在错误,因此对K分布下的MPMF检测方法进行了修正并推导出了正确的虚警表达式.
In the case that the clutter of the polarimetric synthetic aperture radar(PolSAR) imagery follows K distribution,the existing constant false alarm rate(CFAR) detection algorithms based on multi-look polarization whitening filter(MPWF) cannot be applied to the condition that the equivalent number of looks is a non-integer.To solve the problem,a CFAR detection algorithm with analytical false alarm probability expression is proposed.After introducing the Gamma distribution texture under the product model,the probability distribution function(PDF) of the MPWF metric is integrated to obtain its cumulative distribution function(CDF),and then the analytical form of the false alarm probability with respect to the detection threshold is obtained.The simulation results show that the new algorithm has a good false alarm fitting effect.In addition,when the target clutter ratio(TCR) is large,the new algorithm has a higher detection probability.Otherwise,the detection probability is lower than the existing algorithm.It is worth pointing out that the current false alarm probability expression of multi-look polarization matched filter(MPMF) under K distribution is wrong,so the current detection algorithm based on MPMF detection metric is modified and the correct expression of the false alarm probability is derived.
引文
[1] DING Tao,ANFINSEN S N.A comparative study of sea clutter covariance matrix estimators[J].IEEE Geoscience and Remote Sensing Letters,2014,11(5):1010-1014.
[2] 刘涛,崔浩贵,高俊.Wishart分布矩阵行列式值的统计特性及其在参数估计中的应用[J].电子学报,2013,41(6):1231-1237.LIU Tao,CUI Hao-gui,GAO Jun.Statistics of the determinant of the Wishart distributed matrix and its application to parameter estimation[J].Acta Electronica Sinica,2013,41(6):1231-1237.(in Chinese)
[3] 崔浩贵,刘涛,等.基于混合矩的极化SAR图像K分布模型参数估计新方法[J].电子与信息学报,2015,37(2):328-333.CUI Hao-gui,LIU Tao,et al.Parameter estimation for the K-distribution in PolSAR imagery based on hybrid moments[J].Journal of Electronics and Information Technology,2015,37(2):328-333.(in Chinese)
[4] 王娜.极化 SAR图像人造目标检测技术研究[D].湖南长沙:国防科学技术大学.2012.WANG Na.Studies on Polarimetric SAR Imagery Man-made Target Detection[D].Changsha,Hunan:National University of Defense Technology,2012.(in Chinese)
[5] NOVAK L M,BURL M C.Optimal speckle reduction in polarimetric SAR imagery[J].IEEE Transactions on Aerospace and Electronic Systems,1990,26(2):293-305.
[6] LIU G,HUANG S,TORRE A,et al.Optimal speckle reduction in multi-look polarimetric SAR image[A].Proceedings of the 1995 IEEE Geoscience and Remote Sensing Symposium[C].Florence,US:IEEE,1995.664-666.
[7] JIANG Q S,WANG S R,ZOIU D,et al.Automatic detection for ship targets in Radarasat SAR images from coastal regions[A].Proceedings of the 1999 Vision Interface[C].Trois Rivieres,Canada,1999.131-137.
[8] 种劲松,朱敏慧.SAR图像局部窗口K-分布目标检测算法[J].电子与信息学报,2003,25(9):1276-1280.ZHONG Jing-song,ZHU Min-hui.Target detection algorithm of SAR image based on local window K-distribution[J].Journal of Electronics and Information Technology,2003,25(9):1276-1280.(in Chinese)
[9] LIU G Q,HUANG S J,TORRE A,et al.The multilook polarimetric whitening filter (MPWF) for intensity speckle reduction in polarimetric SAR images[J].IEEE Transactions on Geoscience and Remote Sensing,1998,36(3):1016-1020.
[10] KHAN S,GUIDA R.On fractional moments of multilook polarimetric whitening filter for polarimetric SAR data[J].IEEE Transactions on Geoscience and Remote Sensing,2014,52(6):3502-3512.
[11] NESTOR D.On the distribution of the sum of gamma-gamma variates and applications in RF and optical wireless communications[J].IEEE Transactions on Communications,2011,59(5):1298-1308.
[12] 数学手册编写组.数学手册[M].北京:高等教育出版社,2001.
[13] GRADSHTEYN I S,RYZHIK I M.Table of Integrals,Series,and Products (6th edition)[M].New York:Academic Press,1994.
[14] TSIFTSIS T A.Performance of heterodyne wireless optical communication systems over gamma-gamma atmospheric turbulence channels[J].Electronics Letters,2008,44(5):372-373.
[15] NOVAK L M,SECHTIN M B,CARDLLO M J.Studies of target detection algorithms that use polarimetric radar data[J].IEEE Transactions on Aerospace and Electronic Systems,1989,25(2):150-165.
[16] NOVAK L M,BURL M C,IRVING W W,et al.Optimal polrimetric processing for enhanced target detetion[A].Proceedings of the 1991 National Telesystems Conference[C].Atlanta,1991.69-75.
[17] WEI J J,LI P X,YANG J,et al.A new automatic ship detection method using L-band polarimetric SAR imagery[J].IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing,2014,7(4):1383-1393.
