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摘要: 视频合成孔径雷达(SAR)技术将观测场景的动态信息以视频方式呈现出来,其高帧率成像特性有利于实现对地面机动目标的实时探测。视频SAR信号处理关键技术主要包括高帧率成像处理算法和运动目标检测技术等。该文对视频SAR成像处理进行了探讨,给出了两种典型视频SAR成像处理仿真数据结果,详细分析了视频SAR阴影形成机理和对动目标检测性能的影响,并将基于机器学习的视频SAR阴影目标检测技术与经典处理方法在实际数据上进行了验证对比。Abstract: Video Synthetic Aperture Radar (SAR) provides dynamic information about an observation scene in a video to the human eye, which can be very useful for the real-time detection of the ground maneuvering targets. The focusing of video SAR data is demanding because of its high data rate. In this study, we discuss suitable focusing algorithms and presents the obtained simulation results. Further, the shadow formation mechanism is analyzed with respect to target detection. Finally, the machine learning algorithm used for detecting the shadows of the moving targets is compared with the classical image processing methods that use real datasets.
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Key words:
- Video SAR /
- High frame rate imaging /
- Moving target detection /
- Radar imaging /
- Shadow detection
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表 1 仿真参数
Table 1. Simulation parameters
参数名称 数值 单位 雷达载频 $17.6$ ${\rm{GHz}}$ 调频率 $1.5 \times {10^{13}}$ ${\rm{Hz/s}}$ 采样率 $5 \times {10^7}$ ${\rm{Hz}}$ 脉冲重复频率 $1000$ ${\rm{Hz}}$ 脉冲宽度 $4.096 \times {10^{ - 5}}$ ${\rm{s}}$ 载机速度 $180$ ${\rm{m/s}}$ 场景中心斜距 $10000$ ${\rm{m}}$ 载机高度 $6000$ ${\rm{m}}$ 成像擦地角 $36.8$ ° 天线电尺寸 $0.4$ ${\rm{m}}$ 成像帧率 $10$ ${\rm{Hz}}$ 表 2 基于背景差分的阴影检测性能统计
Table 2. Statistical results of shadow detection based on background difference
目标总数 正确检测的目标 虚警目标 漏警目标 730 658 77 72 表 3 基于实测视频SAR数据的检测性能对比(目标总数:730)
Table 3. Comparisons of detection performance on the real video sar data (Target number: 730)
方法 正确检测的目标 虚警目标 漏警目标 基于背景差分的阴影检测方法 658 77 72 Faster-RCNN 607 73 123 Faster-RCNN+滑窗密度聚类 606 9 124 Faster-RCNN+滑窗密度聚类+Bi-LSTM 723 9 7 -
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