【摘要】 应用2004年MODIS的时序NDVI数据,在分析湖北省不同地物类型的NDVI曲线季节性变化特征的基础上,设置对应的阈值,先后将水体、居民地与其他地物类型分离开。将去除了水体和居民地影响的剩余的NDVI序列影像傅立叶变换的1/12频率分量引入到地表覆盖分类的特征空间中,与其最大值影像和平均值影像组合,经过归一量化处理后合成一个类似具有三波段的卫星影像。在合成后的影像上利用最大似然法对其他地类进行分类。研究表明,引入傅立叶变换的特殊频率分量是分析多时相MODIS数据及提取地表植被覆盖信息的有效工具。更多还原

【Abstract】 Fourier transform is presented and applied to monthly composited NDVI data over one year derived from MODIS to examine the frequency distribution of the multi-temporal signal. It is shown that frequencies of the time series of NDVI are linked to integrated NDVI and seasonal variabilities of different periods of the land cover types. The 1/12 month-1 frequency component summarizes the relative dominance of annual habit of land cover types over Hubei province. The introduction of these characteristic phenology parameters extracted from time series of NDVI into feature space improves the separabilities. This research indicates that Fourier transform provides a useful tool for handling temporal sequences of MODIS data and studying the vegetation phenology.更多还原