基于Sentinel-1/2数据融合的县域农业大棚提取

    Extracting county-level agricultural greenhouses using Sentinel-1/2 data fusion

    • 摘要: 农业大棚作为一种特殊的地物类型,在高空间分辨率遥感影像上识别相对容易且精度高,但高分影像大多需商业购买,可获取性受限。为提高县域农业大棚精确提取的经济性和便捷性,该研究利用免费、方便获取的非高分Sentinel-1(雷达)和Sentinel-2(光学)遥感数据进行融合,结合光谱指数、纹理提取和主成分分析等方法,构建了多维特征集空间,采取多种分类识别方法(案),对县域农业大棚进行识别提取。研究结果表明:1)仅使用Sentinel-1/2(10 m分辨率)遥感影像,在适当分类方法(案)的支持下,可实现县域农业大棚的高精度提取;2)利用Sentinel-1(雷达)和Sentinel-2(光学)遥感数据的融合有助于提升农业大棚的识别精度。Sentinel-1/2数据融合相较于仅使用Sentinel-2(光学)遥感数据,总体精度平均提升1.70个百分点,最大提升3.29 个百分点;3)文中所用识别方法(案)中,面向对象方法在大棚密度高的区域表现良好;但在大棚密度较低的区域,精度一般,表现出较强的区域(或场景)依赖性。而光学与雷达信息融合后基于像素的递归特征消除随机森林(random forest - recursive feature elimination,RF-RFE)方法(案)平均精度可达96.45%,精度高且稳定,区域适应性强,适合非高分影像县域农业大棚的精确、高效提取。研究提出的基于Sentinel-1/2影像县域农业大棚提取方案,可为广大县域农业大棚经济、快速、高效提取,提供技术支持。

       

      Abstract: As a special feature type, agricultural greenhouses were relatively easy to recognize on high spatial resolution remote sensing images with high accuracy. However, most high spatial resolution images had to be purchased commercially, and their availability was limited. In order to improve the economy and convenience of precise extraction of county-level agricultural greenhouses, this study used free and easily available non high spatial resolution Sentinel-1 (radar) and Sentinel-2 (optical) remote sensing images for data fusion, combined with spectral index, texture extraction, principal component analysis and other methods, to construct a multidimensional feature set space, and adopted multiple classification and recognition methods (cases) to identify and extract county-level agricultural greenhouses. The results indicated that: 1) The county’s agricultural greenhouses could be extracted with high precision by utilizing just Sentinel-1/2 (10 m resolution) remote sensing images, bolstered by suitable classification techniques (case). 2) The fusion of Sentinel-1 (radar) and Sentinel-2 (optical) remote sensing data could be helpful for improving the recognition accuracy of agricultural greenhouses. Compared to using only Sentinel-2 (optical) remote sensing data, the overall accuracy of Sentinel-1/2 data fusion had improved by an average of 1.70 percentage points, with a maximum improvement of 3.29 percentage points; 3) Of all the classification and recognition techniques (case) applied in the paper, the object-oriented method performed well in areas with high greenhouse density; But in areas with low greenhouse density, the accuracy was mediocre and exhibited a strong dependence on region (or scene). After the fusion of optical and radar information, the pixel based recursive feature elimination random forest (RF-RFE) method can achieve an average accuracy of 96.45%, with high and stable accuracy and strong regional adaptability. It was suitable for accurate and efficient extraction of agricultural greenhouses from non high-resolution image in county-level. The technical solution proposed in this paper based on Sentinel-1/2 images, could be provided technical support for the economic, rapid, and efficient extraction of agricultural greenhouses in most counties.

       

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