面向亚像元级积雪信息提取的MODIS影像波段融合方法研究

MODIS影像因其共享性和时间序列的完整性而成为大区域积雪监测研究广泛使用的数据源,进行MODIS影像波段间融合,能够为积雪研究提供较高分辨率的影像数据源。为了充分利用MODIS影像250 m分辨率波段的空间和光谱信息,提取亚像元级的积雪面积,使用两种具有高光谱保真度的影像融合方法：基于SFIM变换和基于小波变换的融合方法,采取不同的波段组合策略,对MODIS影像bands 1~2和bands 3~7进行融合,并以Landsat TM影像的积雪分类图作为“真值”,对融合后影像进行混合像元分解得到的积雪丰度图的精度进行评价。结果表明：利用基于SFIM变换和小波变换方法融合后影像提取的积雪分类图精度较高,数量精度为75%,比未融合影像积雪分类图的精度提高了6%,表明MODIS影像波段融合是一种提取高精度积雪信息的有效方法。

A Study on MODIS Image Fusion Methods for Sub-pixel Snow Extraction

Because of its sharing and high time resolution,MODIS image has became the widely used data source in large area snow monitoring research.Fusion between MODIS image bands can provide a higher resolution image data source for snow study.In order to utilize the spatial and spectral information of MODIS 250m bands data effectively,this paper takes band 1 and/ or band 2 as the high resolution images and uses the remote sensing image fusion methods SFIM and wavelet transform to fuse bands 3~7.The fused image was input into the line spectral mixture model to extract snow area at sub-pixel scale.In addition,the accuracy of the extracted snow area was assessed by the Landsat TM snow maps,which was used as the “truth value”.The results show that the quantity accuracy of snow cover area gotten form fused image is 75% ,increased by 6% than that of generated form unfused image and band fuse of MODIS images is an effective way to extract high accuracy snow information.