中圖分類號:S812;TP751 文獻標識碼:A 文章編號:2095-5553(2025)07-0111-07
Abstract:Inorder toextractdesert grassland fractionalvegetationcoverage inrealtime,accuratelyandquickly,this paper proposedalightweightnetwork model method integrated atention mechanism(Lightweightnetwork-Convolutional Block Atention Module,LW—CBAM)based on the collected UAV hyperspectral remote sensing data.This method improved the traditional 2Dconvolution kernel to 3Ddeeplyseparableconvolution kernel,andcombined the multi-branch methodand theatention mechanismmoduletomakethe modellightweightandimprovedtheaccuracyof themodel.Inordertoobtain the optimal model,this paperoptimized the batch size and learning rateof the model.Theresultsshowed thatcompared with popular deep learning methods such as ResNet34,VGG16,MobileNetV2andMobileNetV3,LW—CBAM had a higher classification accuracy,OA was 98.97% , Kappa coefficient was 97.94,and the model had a higher estimation accuracy for fractional vegetation coverage.The absolute error from the true value was only 0.17% .TheLW— CBAM's parameter count was reduced by over 90% compared to the other models,and its computational requirements were respectively 1.37% , 0.74% , 13.33% ,and 14.81% of the four other models. During the model validation stage,the estimation error of fractional vegetation coverage by LW—CBAM was below 0.3% . This model provided a feasible method for estimating fractional vegetation coverage in desert steppe and provided a basis for grassland degradation control.
Keywords:fractional vegetation coverage;hyperspectral remote sensing;deep learning;lightweight network; attention mechanism;desert steppe
0 引言
草原是我國生態系統中不可或缺的一部分[1]。我國的草地面積將近 4×108hm2 ,居世界第二位[2]。然而,自從20世紀60年代以來,草原退化現象在全國各地出現上升趨勢[3],黨的二十大報告指出,推行草原森林河流湖泊濕地休養生息,提升生態系統多樣性、穩定性、持續性。全國第六次荒漠化和沙化土地監測調查結果顯示,內蒙古荒漠化土地占全國荒漠化土地面積的 23.04%[4] ,土地沙化、次生鹽漬化嚴重,生態修復的任務艱巨[5]
草原荒漠化主要表現為植被蓋度(FVC)減少、植被種類減少、裸地面積增加等,因此, FVC 是荒漠化監測的重要指標[6。傳統的植被蓋度監測方法以地面實測為主,優點是精度高、數據可靠,但只能在小范圍內進行植被蓋度計算[7]。得益于技術的發展,衛星遙感法可以在大范圍內對植被蓋度進行反演,但其分辨率不夠高,成本也比較高昂[8]。近年來,無人機(UAV)搭載高光譜儀借助成本低、分辨率高、操作靈活等優勢迅速被大范圍應用9,可為荒漠草原植被蓋度的計算提供技術支持。
1數據采集與預處理
植被蓋度通常被定義為植被(包括枝、莖、葉)在單位面積內的垂直投影面積所占百分比[10]。張燕斌等[11]采用改進的3D—ResNet模型對荒漠草原地物進行分類,其總體分類精度為 97.73% ,為荒漠草原整體生態系統研究奠定基礎; Xu 等[12]提出了MSR—3DCNN模型用于高光譜圖像分類,并在3個開源數據集上進行試驗。深度可分離卷積(DSC)[13]降低了模型參數量,為深度學習模型的輕量化提供新思路。……