利用Sentinel-2光谱指数和改进的单类随机森林的塑料大棚提取方法
A method for plastic greenhouse extraction integrating Sentinel-2 spectral indices and an improved one-class random forest
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摘要: 塑料大棚在现代农业中得到广泛应用,但其使用也带来了一些生态环境问题。利用遥感数据能够有效进行大范围的塑料大棚提取与识别,但现有的研究常采用分类法或光谱指数法提取塑料大棚,缺乏对2种方法的结合与对比分析。因此,该文提出一种利用多个Sentinel-2光谱指数结合单类分类方法(即改进的单类随机森林)的塑料大棚提取方法。该方法将6种塑料大棚光谱指数作为特征,使用改进的单类随机森林方法提取塑料大棚,并与该文提出的方法进行对比,以验证该方法的有效性。结果表明: 该方法在4个季节图像的提取结果的总体精度(overall accuracy,OA)均在97%以上,Kappa系数高于0.82,F1高于0.84,均高于6个指数的提取精度。同时,该文方法在不同季节提取的OA差异在1%以内,Kappa系数与F1分数的差异在0.1以内,季节稳定性强,均优于单独使用光谱指数的塑料大棚提取结果。研究可为准确监测塑料大棚空间分布提供科学依据和参考意见。Abstract: Plastic greenhouses have gained extensive application in modern agriculture. This, however, gives rise to ecological issues. Remote sensing data enable effective extraction and identification of plastic greenhouses on a large scale. Existing studies largely focus on plastic greenhouse extraction using either classification or spectral indices methods. However, there exists a lack of the combination and comparative analysis of both methods. This study proposed a method for plastic greenhouse extraction that integrates multiple Sentinel-2 spectral indices and a one-class classification method (improved one-class random forest). Furthermore, this study extracted information on plastic greenhouses using an improved one-class random forest method, as well as six spectral indices of plastic greenhouses as classification features. The extraction results were then compared with those of the proposed method to demonstrate the effectiveness of the latter. The results indicate that the proposed method yielded an overall accuracy of above 97% across four seasons, with kappa coefficients exceeding 0.82 and F1 scores of over 0.84. These metrics all were better than those yielded using the six spectral indices. Furthermore, the proposed method exhibited differences in the overall accuracy, kappa coefficient, and F1 score across four seasons of less than 1%, under 0.1, and below 0.1 respectively. This suggests the high seasonal stability of the method, outperforming the extraction results obtained by using spectral indices alone. This study provides a method for accurately monitoring the spatial distribution of plastic greenhouses.
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