基于时序相干建模的SAR相干变化检测方法

    SAR Coherent Change Detection Method Based on Temporal Coherence Modeling

    • 摘要: 相干变化检测技术可广泛应用于环境监测、城市规划和灾害评估领域,通过对比检测多时相SAR影像中的低相干区域来识别场景中的细微变化。然而阴影、水体等低信噪比区域,或场景内风吹草动形成的时变地表特征会引起低相干杂波,使车辙、足迹等低相干目标的检测变得困难。针对该问题,本文提出一种基于时序相干建模的SAR相干变化检测方法。该方法构建三类时序隐藏状态刻画地物演化规律,引入概率隶属度软判别机制拟合渐变、间歇等复杂时序特征;通过时序自适应转移矩阵与SAR相干统计量校准模型参数,实现无监督建模;并依托维特比算法解码最优时序状态序列,完成精细化变化判别。仿真与机载实测实验结果表明,相较于传统相干变化检测方法,本文方法可有效抑制自然时变杂波干扰,在保证微弱人造变化高检测灵敏度的同时,显著提升复杂野外场景的检测精度与稳定性。

       

      Abstract: Synthetic Aperture Radar coherent change detection(SAR CCD) is widely used in environmental monitoring, urban planning and disaster assessment to identify subtle surface variations via low-coherence region analysis of multi-temporal SAR images. Nevertheless, low signal-to-noise ratio areas (e.g., shadows and water bodies) and time-varying surface features induced by vegetation fluctuations will produce massive low-coherence clutter, greatly limiting the detection performance of faint artificial targets such as tire tracks and footprints. To solve this problem, this paper proposes a temporal coherence modeling-based SAR coherent change detection method. Three temporal hidden states are constructed to describe the evolution characteristics of ground objects, and a probabilistic membership soft decision mechanism is introduced to fit complex temporal variations including gradual changes and intermittent disturbances. The temporal adaptive transition matrix and SAR coherence statistics are employed to calibrate model parameters and achieve unsupervised modeling. The Viterbi algorithm is further adopted to decode the optimal temporal state sequence for refined change discrimination. Simulated and airborne experimental results show that the proposed method can effectively suppress natural time-varying clutter interference. It significantly improves the detection accuracy and robustness of SAR coherent change detection in complex field scenarios while preserving high sensitivity to subtle artificial changes.

       

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