ConvLSTM神经网络的时序InSAR地面沉降时空预测

Spatiotemporal Prediction of Time-Series InSAR Land Subsidence Based on ConvLSTM Neural Network

  • 摘要: 现有地面沉降时空预测方法存在时序特征捕捉能力差,未顾及空间邻域特征等问题,导致地面沉降时空预测的可靠性差。采用合成孔径雷达干涉测量技术(interferometric synthetic aperture radar,InSAR),提出了一种能够捕捉时序特征和空间邻域特征的卷积长短时记忆(convolutional long short-term memory, ConvLSTM)神经网络地面沉降时空预测方法。选取北京首都国际机场作为研究区,首先基于差分干涉测量短基线集InSAR(small baseline subset InSAR,SBAS-InSAR),利用Sentinel-1A影像获取地面沉降时空InSAR数据,然后构建ConvLSTM的地面沉降时空预测模型,模拟预测该区域未来一年的地面沉降。利用永久散射体干涉测量技术、SBAS-InSAR结果和水准点数据,交叉验证了时序InSAR结果的可靠性;时序InSAR地面沉降数据采用滑动窗口进行数据分割,形成多对一数据集模式;结合小波变换和评价指标确定时空预测模型的最佳时间步长,建立时序InSAR地面沉降的ConvLSTM时空预测模型。实验结果显示,所提模型的预测结果和真实结果的拟合度R2达到0.997,基于图像评价指标结构相似性(structural similarity,SSIM)和多尺度结构相似性(multi-scale structural similarity,MS-SSIM)进一步评价了模型的性能,SSIM和MS-SSIM分别达到了0.914、0.975。此外,与支持向量回归、多层感知器、卷积神经网络和长短时记忆神经网络模型进行了对比分析,各项指标均显示所提模型最优。所提模型预测到2022年11月北京首都国际机场最大累积沉降量达到157 mm,研究成果可为城市地面沉降早期预防提供关键技术支撑。

     

    Abstract:
    Objective The existing spatiotemporal prediction methods of land subsidence have some problems, such as poor ability to capture time-series features and ignoring spatial neighborhood features, which lead to poor reliability of spatiotemporal prediction of land subsidence.
    Method This paper proposes a spatiotemporal prediction of land subsidence based on convolutional long short-term memory (ConvLSTM) neural network, which can capture time-series features and spatial neighborhood features. First, based on small baseline subset interferometric synthetic aperture radar (SBAS-InSAR), Sentinel-1A images were used to obtain the spatiotemporal InSAR data of land subsidence at Beijing Capital International Airport (BCIA). Then, a ConvLSTM model is constructed to predict the land subsidence in the next year. Permanent scatters InSAR, SBAS-InSAR and benchmark results are used to cross-verify the reliability of time-series InSAR results. Time-series InSAR land subsidence data are segmented by sliding windows to form a many-to-one dataset model. Combined with wavelet transform and evaluation indexes to determine the optimal time step of the prediction model, the ConvLSTM spatiotemporal prediction model of time-series InSAR land subsidence is established.
    Results The R2 of the predicted and real results reaches 0.997. Meanwhile, the performance of the proposed model is further evaluated based on the image evaluation index structural similarity (SSIM) and multi-scale structural similarity (MS-SSIM), which reach 0.914 and 0.975, respectively. In addition, support vector regression, multilayer perceptron, convolutional neural network and the long-term memory neural network model are compared and analyzed, and each index reveales that the proposed model is optimal.
    Conclusion The ConvLSTM spatiotemporal prediction model predicts that the maximum cumulative subsidence at BCIA will reach 157 mm by November 2022. This study can provide key technical support for the early prevention of urban land subsidence.

     

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