摘要:
针对现有面向滑坡易发性评价的深度学习网络在不同层次的网络结构中往往仅利用单一尺度特征信息以及模型复杂造成庞大的参数数量和计算复杂度的问题,提出多尺度特征学习的轻量化滑坡易发性评价方法(lightweight network based on multi-scale feature learning,MFL-LN),利用深度特征增强模块(deep feature enhancementmodule,DFEM)和多尺度特征融合模块(multi-scale feature fusion module,MSFF)建立多尺度特征学习轻量化网络,挖掘滑坡易发性与评价因子之间的深层次关联关系。引入通道增强的注意力机制和深度可分离卷积构建DFEM,动态学习不同通道特征的关注度,增强模型对重要特征的感知和利用能力;将传统卷积优化为深度可分离卷积,能减少参数数量和计算量,实现模型轻量化。采用空洞空间金字塔池化策略优化设计MSFF,对编码部分下采样提取的特征进行多尺度融合,在融合后的深层特征上进行信息交互,同时自适应地调整特征权重,更好地捕捉滑坡区域的全局和局部空间特征,以弥补下采样带来的特征损失。以陕西省安康市为研究区开展滑坡易发性分析,与支持向量机(support vector machine,SVM)模型、多维CNN耦合(multi-dimensional convolutional neural network coupled,Multi-CNN)模型、深度可分离卷积神经网络(depthwise separable convolutional neural network,DS-CNN)模型、多尺度卷积神经网络(multi-scale convolutional neural network,MSCNN)模型、轻量级可分离因式卷积网络(lightweight separable factorized convolution network,SFCNet)模型进行对比,从易发性评价模型精度和模型性能轻量化两个角度综合分析,结果表明提出的MFL-LN方法能有效降低模型训练成本,提高滑坡易发性预测的精度,易发性分区效果更好。
Abstract:
Objectives: Landslide susceptibility assessment can provide scientific basis and technical support for disaster prevention and mitigation. In Ankang City, the unique topography of "three mountains enclosing two rivers" results in a varied landscape and complex geological structures. Additionally, factors such as engineering projects, land use, and heavy rainfall contribute to the frequent occurrence of landslides. In response to the challenges of inaccurate landslide prediction caused by using single-scale feature extraction in different levels of network structures, and the high resource demands and computational costs due to model complexity, the lightweight network based on multi-scale feature learning (MFL-LN) for landslide susceptibility assessment is proposed. Methods: Combining the geological environment characteristics of landslide development in the study area, the Spearman correlation analysis was conducted on evaluation factors. This analysis led to the identification of 13 evaluation factors across four categories: human activity factors (distance to roads, distance to settlements), hydrological factors (annual rainfall, distance to rivers), topographical factors (elevation, slope, aspect, plan curvature, profile curvature, aspect variability, slope variability, and landform), and vegetation factor (normalized difference vegetation index). These factors were used to establish a landslide susceptibility evaluation factor system for the study area. To ensure the randomness and rationality of negative sample selection, distance constraints were applied, such as maintaining a minimum distance of 500 meters between hazard and non-hazard points, as well as between non-hazard points. Nonhazard units were randomly selected to match the number of hazard units, forming a balanced sample dataset. The MFL-LN method employed the deep feature enhancement module (DFEM) to construct the network architecture, reducing the number of parameters and computational load to achieve model lightweighting. Additionally, it dynamically adjusted the attention to different channel features, enhancing the model's ability to perceive and utilize important features. Subsequently, the multi-scale feature fusion module (MSFF) was employed to integrate the features extracted through down-sampling in the encoding phase, enabling information interaction on the fused deep features and adaptively adjusting the feature weights. It can effectively capture both global and local spatial characteristics of landslides and compensate for the feature extraction loss caused by down-sampling, thereby improving the model's predictive capability for landslide susceptibility. Results: An ablation study was conducted on the MFL-LN method, and it was compared with the support vector machine (SVM) model, multi-dimensional convolutional neural network coupled (Multi-CNN) model, depthwise separable convolutional neural network (DS-CNN) model, multi-scale convolutional neural network (MSCNN) model, and lightweight separable factorized convolution network (SFCNet) model. The accuracy of the susceptibility evaluation models was analyzed from three perspectives: landslide susceptibility zoning maps, landslide hazard point density zoning statistics, and evaluation model accuracy. The hazard point density for very low and very high susceptibility areas in the MFL-LN model was 0.009 and 0.557, respectively, ensuring that the hazard point density is lower in very low susceptibility areas and highest in very high susceptibility areas. Additionally, the area under the receiver operating characteristic (ROC) curve was the highest at 0.837. The model was analyzed for lightweight optimization based on parameter count and floating-point operations. The parameter count of the MFL-LN model was 0.081, and the floating-point operation count was 41.102. This effectively reduced the model training costs and improved the accuracy of landslide susceptibility zoning. Conclusions: By selecting Ankang City in Shaanxi Province as the study area and analyzing the historical landslide hazard data, the MFL-LN model was constructed utilizing the DFEM and MSFF with an encoder-decoder structure to evaluate landslide susceptibility. This approach improved computational efficiency while maintaining the model's performance, making the landslide prediction model more efficient and practical.