MODIS水稻面积提取中独立成分端元丰度校正方法

    Endmember abundance calibration method for paddy rice area extraction from MODIS data based on independent component analysis

    • 摘要: 为了解决独立成分分析中端元丰度校正结果同实际丰度相差较大的问题,该文提出了一种基于回归分析的独立成分端元丰度校正方法。具体是:首先应用ICA对遥感时序数据进行分解,获取目标地物的ICA分解结果;再抽选一定量的样本,将样本目标地物的真实丰度与ICA分解结果进行回归;最后根据回归关系推算每个像元的目标地物丰度。基于MODIS时序数据,将该文方法和线性拉伸方法应用于江苏兴化地区的水稻面积提取,并将2种方法的提取结果同水稻准真值图像进行对比。分析结果表明,该文方法得到的水稻丰度图像的均方根误差、偏差在不同的空间尺度下均小于线性拉伸方法,而不同空间尺度下的决定系数(R2)均高于线性拉伸方法。与线性拉伸方法相比,该文方法能获得更接近实际情况的端元丰度校正结果,增强了ICA在农作物面积提取中的应用能力,为大尺度农作物识别和面积提取提供了依据。

       

      Abstract: There is a large discrepancy between the actual abundance of land cover and the result derived from the endmember abundance calibration of Independent Component Analysis (ICA). In order to solve this problem, this paper proposed a new method for the endmember abundance calibration of ICA by combining regression analysis. The new method includes 3 steps: Firstly, decomposing the remote sensing time-series data to obtain the independent component of the object feature. Secondly, selecting a certain amount of samples with actual object feature abundance and then building the relationship between the actual abundance and derived independent component using regression analysis. Finally, using regression relationship to derive the abundance of object feature for each pixel. Based on the MODIS time-series data, the new method and the linear scaling method were applied in Xinghua county, Jiangsu province of China for the mapping of rice abundance. The results derived from these two methods were then compared with the actual rice abundance map of the study area. Results showed that the Root Mean Square Error (RMSE) and Bias of the rice map derived from the new method was all smaller than that by linear scaling method, where the determination coefficient (R2) was all higher than that by linear scaling method at different spatial scales. The new method can enhance the application of ICA model in crop acreage mapping and provide a basis for large-scale crop identification and area extraction.

       

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