传统的CFAR检测应用到光学卫星遥感图像舰船目标检测中时不能对黑极性目标进行判断,针对此提出改进的基于广义似然比检验(Generalized Likelihood Ratio Test,GLRT)的舰船目标检测算法。该算法采用滑动窗口检测形式,在假设背景和目标灰...传统的CFAR检测应用到光学卫星遥感图像舰船目标检测中时不能对黑极性目标进行判断,针对此提出改进的基于广义似然比检验(Generalized Likelihood Ratio Test,GLRT)的舰船目标检测算法。该算法采用滑动窗口检测形式,在假设背景和目标灰度均服从高斯分布的前提下,通过GLRT判断背景窗口与目标窗口是否同分布来检测目标,兼顾了目标黑白两种极性的情况。算法实现中对图像进行了分块检测,并通过形态学处理对检测结果进行了目标聚类。采用SPOT5与CBERS实测数据进行实验,验证了海背景服从高斯分布的假设。典型数据检测结果表明,该算法可以检测黑极性目标,且相比CFAR虚警率更低,大量数据计算ROC曲线的结果以及比CFAR检测少约40%的耗时进一步表明该算法性能更优。展开更多
为了从环境中检测出相位量化数字射频存储器(Digital radio frequency memory,DRFM)欺骗干扰的存在,本文设计了一种能够在均匀环境中检测出噪声、干扰或回波信号的自适应检测器。检测过程分为两步:先由基于广义似然比检测(Generalized l...为了从环境中检测出相位量化数字射频存储器(Digital radio frequency memory,DRFM)欺骗干扰的存在,本文设计了一种能够在均匀环境中检测出噪声、干扰或回波信号的自适应检测器。检测过程分为两步:先由基于广义似然比检测(Generalized likelihood ratio test,GLRT)的自适应匹配滤波(Adaptive matched filter,AMF)检测器完成噪声和"信号"(滤波后的回波信号或干扰)的检测;再从回波信号和干扰导引矢量间的差异性出发重新设计检测器,以甄别回波信号或干扰。最后,通过理论推导和蒙特卡洛试验对检测器的性能进行分析和评估,并与透视检测器进行比较。仿真结果表明,在低相位量化位数和高信噪比的条件下,所设计的检测器能够正确检测出干扰信号的存在。展开更多
As traditional two-parameter constant false alarm rate （CFAR） target detec-tion algorithms in SAR images ignore target distribution, their performances are not the best or near best. As the resolution of SAR images ...As traditional two-parameter constant false alarm rate （CFAR） target detec-tion algorithms in SAR images ignore target distribution, their performances are not the best or near best. As the resolution of SAR images increases, small targets present more pixels in SAR images. So the target distribution is of much significance. Distribution-based CFAR detection algorithm is presented. We unite the pixels around the test cell, and estimate the distribution of test cell by them. Generalized Likelihood Ratio Test （GLRT） is used to deduce the detectors. The performance of the distribution-based CFAR （DBCFAR） detectors is analyzed theoretically. False alarms of DBCFAR detection are fewer than those of CFAR at the same detection rate. Finally experiments are done and the results show the performance of DBCFAR is out of conventional CFAR. False alarms of DBCFAR detection are concentrated while those of CFAR detection are dispersive.展开更多
利用球不变随机矢量(Spherically Invariant Random Vector,SIRV)描述非均匀杂波,建立了双基地多输入多输出(Multiple-Input Multiple-Qutput,MIMO)雷达距离扩展目标的信号检测模型,提出了距离扩展目标的两步广义似然比检测(Generalized...利用球不变随机矢量(Spherically Invariant Random Vector,SIRV)描述非均匀杂波,建立了双基地多输入多输出(Multiple-Input Multiple-Qutput,MIMO)雷达距离扩展目标的信号检测模型,提出了距离扩展目标的两步广义似然比检测(Generalized Likelihood Ratio Test,GLRT)算法.首先,根据目标散射系数的两种假设模型,分别推导确定型目标、高斯型目标GLRT检测器的解析表达式,然后利用固定点迭代算法估计杂波协方差矩阵,获得自适应GLRT(AD-GLRT和AG-GLRT)检测器.仿真实验表明:AD-GLRT和AG-GLRT检测器的检测性能均优于非均匀杂波背景、高斯杂波背景下点目标的检测性能,且两者的检测性能相当,并且虚拟阵元数、目标分布的距离单元数,以及信杂比越大,两者的检测性能越好.展开更多
The problem of adaptive detection in the situation of signal mismatch is considered; that is, the actual signal steering vector is not aligned with the nominal one. Two novel tunable detectors are proposed. They can c...The problem of adaptive detection in the situation of signal mismatch is considered; that is, the actual signal steering vector is not aligned with the nominal one. Two novel tunable detectors are proposed. They can control the degree to which the mismatched signals are rejected. Remarkably, it is found that they both cover existing famous detectors as their special cases. More importantly, they possess the constant false alarm rate（CFAR）property and achieve enhanced mismatched signal rejection or improved robustness than their natural competitors. Besides, they can provide slightly better matched signals detection performance than the existing detectors.展开更多
对于非均匀杂波环境下信号自适应检测问题,由于待测数据样本的协方差矩阵与训练数据的协方差矩阵不相同,造成检测性能下降,针对此问题本文提出了基于贝叶斯方法的广义似然比检测器(Bayesian generalized likelihood ratio test,B-GLRT)...对于非均匀杂波环境下信号自适应检测问题,由于待测数据样本的协方差矩阵与训练数据的协方差矩阵不相同,造成检测性能下降,针对此问题本文提出了基于贝叶斯方法的广义似然比检测器(Bayesian generalized likelihood ratio test,B-GLRT).通过对非均匀杂波环境下协方差矩阵间的关系进行统计建模,使在B-GLRT的设计过程中能够结合杂波的非均匀性,并且这种非均匀性在统计模型中可以通过标量参数调节.同时通过对协方差矩阵选择合适的先验分布,使B-GLRT能够融合有助于提高检测性能的先验知识.通过仿真实验,验证了B-GLRT的检测性能高于传统的非贝叶斯检测器,并且分析了杂波环境非均匀性和先验信息对自适应检测性能的影响.展开更多
文摘传统的CFAR检测应用到光学卫星遥感图像舰船目标检测中时不能对黑极性目标进行判断,针对此提出改进的基于广义似然比检验(Generalized Likelihood Ratio Test,GLRT)的舰船目标检测算法。该算法采用滑动窗口检测形式,在假设背景和目标灰度均服从高斯分布的前提下,通过GLRT判断背景窗口与目标窗口是否同分布来检测目标,兼顾了目标黑白两种极性的情况。算法实现中对图像进行了分块检测,并通过形态学处理对检测结果进行了目标聚类。采用SPOT5与CBERS实测数据进行实验,验证了海背景服从高斯分布的假设。典型数据检测结果表明,该算法可以检测黑极性目标,且相比CFAR虚警率更低,大量数据计算ROC曲线的结果以及比CFAR检测少约40%的耗时进一步表明该算法性能更优。
文摘为了从环境中检测出相位量化数字射频存储器(Digital radio frequency memory,DRFM)欺骗干扰的存在,本文设计了一种能够在均匀环境中检测出噪声、干扰或回波信号的自适应检测器。检测过程分为两步:先由基于广义似然比检测(Generalized likelihood ratio test,GLRT)的自适应匹配滤波(Adaptive matched filter,AMF)检测器完成噪声和"信号"(滤波后的回波信号或干扰)的检测;再从回波信号和干扰导引矢量间的差异性出发重新设计检测器,以甄别回波信号或干扰。最后,通过理论推导和蒙特卡洛试验对检测器的性能进行分析和评估,并与透视检测器进行比较。仿真结果表明,在低相位量化位数和高信噪比的条件下,所设计的检测器能够正确检测出干扰信号的存在。
文摘As traditional two-parameter constant false alarm rate （CFAR） target detec-tion algorithms in SAR images ignore target distribution, their performances are not the best or near best. As the resolution of SAR images increases, small targets present more pixels in SAR images. So the target distribution is of much significance. Distribution-based CFAR detection algorithm is presented. We unite the pixels around the test cell, and estimate the distribution of test cell by them. Generalized Likelihood Ratio Test （GLRT） is used to deduce the detectors. The performance of the distribution-based CFAR （DBCFAR） detectors is analyzed theoretically. False alarms of DBCFAR detection are fewer than those of CFAR at the same detection rate. Finally experiments are done and the results show the performance of DBCFAR is out of conventional CFAR. False alarms of DBCFAR detection are concentrated while those of CFAR detection are dispersive.
文摘利用球不变随机矢量(Spherically Invariant Random Vector,SIRV)描述非均匀杂波,建立了双基地多输入多输出(Multiple-Input Multiple-Qutput,MIMO)雷达距离扩展目标的信号检测模型,提出了距离扩展目标的两步广义似然比检测(Generalized Likelihood Ratio Test,GLRT)算法.首先,根据目标散射系数的两种假设模型,分别推导确定型目标、高斯型目标GLRT检测器的解析表达式,然后利用固定点迭代算法估计杂波协方差矩阵,获得自适应GLRT(AD-GLRT和AG-GLRT)检测器.仿真实验表明:AD-GLRT和AG-GLRT检测器的检测性能均优于非均匀杂波背景、高斯杂波背景下点目标的检测性能,且两者的检测性能相当,并且虚拟阵元数、目标分布的距离单元数,以及信杂比越大,两者的检测性能越好.
基金supported by the National Natural Science Foundation of China(6110216960925005)
文摘The problem of adaptive detection in the situation of signal mismatch is considered; that is, the actual signal steering vector is not aligned with the nominal one. Two novel tunable detectors are proposed. They can control the degree to which the mismatched signals are rejected. Remarkably, it is found that they both cover existing famous detectors as their special cases. More importantly, they possess the constant false alarm rate（CFAR）property and achieve enhanced mismatched signal rejection or improved robustness than their natural competitors. Besides, they can provide slightly better matched signals detection performance than the existing detectors.
文摘对于非均匀杂波环境下信号自适应检测问题,由于待测数据样本的协方差矩阵与训练数据的协方差矩阵不相同,造成检测性能下降,针对此问题本文提出了基于贝叶斯方法的广义似然比检测器(Bayesian generalized likelihood ratio test,B-GLRT).通过对非均匀杂波环境下协方差矩阵间的关系进行统计建模,使在B-GLRT的设计过程中能够结合杂波的非均匀性,并且这种非均匀性在统计模型中可以通过标量参数调节.同时通过对协方差矩阵选择合适的先验分布,使B-GLRT能够融合有助于提高检测性能的先验知识.通过仿真实验,验证了B-GLRT的检测性能高于传统的非贝叶斯检测器,并且分析了杂波环境非均匀性和先验信息对自适应检测性能的影响.
