基于混响感知自适应稀疏子空间跟踪的浅水运动小目标检测
Reverberation-aware adaptive sparse subspace tracking for moving small target detection in shallow water
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摘要: 针对固定或低速运动平台下浅水混响较强、运动小目标回波易被淹没的问题, 提出一种混响感知自适应稀疏子空间跟踪方法。该方法利用混响背景的低秩相干性与相对运动目标的局部稀疏性差异, 根据局部背景功率统计构造空间加权矩阵, 降低强混响区域对子空间估计的影响; 通过逐帧递推更新跟踪背景子空间, 并引入列稀疏约束抑制目标亮点和异常散射对背景基的污染; 最后由正交补残差提取目标响应。仿真结果表明, 所提方法在低信噪比条件下能够提高综合检测性能并减少误检。湖试和浅海海试数据处理结果进一步表明, 所提方法能够有效抑制混响, 并改善运动小目标检测效果, 单帧处理时间约88 ms, 可支持逐帧在线处理。Abstract: To address the problem that moving small-target echoes are easily submerged by strong shallow-water reverberation under fixed or slowly moving platforms, a reverberation-aware adaptive sparse subspace tracking method is proposed. The method exploits the difference between the low-rank coherence of reverberation background and the local sparsity of targets with relative motion. A spatial weighting matrix is constructed from local background power statistics to reduce the influence of strong reverberation regions on subspace estimation. The background subspace is tracked through frame-by-frame recursive updating, and a column-wise sparse constraint is introduced to suppress contamination of the background bases by target highlights and abnormal scatterers. Target responses are then extracted from the orthogonal-complement residual. Simulation results show that the proposed method improves overall detection performance and reduces false alarms caused by reverberation residuals under low signal-to-noise ratio conditions. Lake-trial and shallow-sea trial results further demonstrate that the proposed method effectively suppresses reverberation residuals and improves moving small-target detection performance. The average processing time per frame on the lake-trial data is about 88 ms, supporting frame-by-frame online processing.
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