Sentinel-2卫星影像融合方法与质量评价分析

Sentinel-2 Satellite Image Fusion Method and Quality Evaluation Analysis

Sentinel-2卫星传感器获取的是3种不同空间分辨率的光学遥感影像,如何通过融合方法提高较低空间分辨率波段的空间分辨率成为Sentinel-2数据应用面临的问题之一。以Sentinel-2B影像为数据源,利用相关系数最大法、中心波长最近邻法、像元值最大法和主成分分析等4种方法从4个10m分辨率的波段中产生一个高分辨率波段;采用主成分分析、高通滤波、小波变换、Gram-Schmidt变换以及Pansharp共5种融合方法,对产生的高分辨率数据和6个20m分辨率的多光谱数据进行融合,并从定性、定量(信息熵、平均梯度、光谱相关系数、均方根误差和通用图像质量指数)以及融合影像的分类精度3个方面对融合效果进行评价,结果表明:相关系数最大法的Pansharp方法融合图像质量优于其他融合方法,分类精度略低于最高的像元值最大法的GS方法,并且远高于4个原始10m分辨率的多光谱影像的分类精度。从实验数据的分类精度分析,不同融合方法在不同地物提取中各有优势,在实际应用中,应根据实际研究需要,选择适宜的方案。该研究可为Sentinel-2卫星以及相似卫星数据处理和应用提供参考。

Sentinel-2 satellite sensors acquire three kinds of optical remote sensing images with different spatial resolutions.How to improve the spatial resolution of lower spatial resolution bands by fusion method is one of the problems faced by Sentinel-2 applications.Taking the Sentinel-2 B image as the data source,a high spatial resolution band was generated or selected from the four 10 m spatial resolution bands by four methods:the maximum correlation coefficient,the central wavelength nearest neighbor,the pixel maximum and the principal component analysis.We fused the one high spatial resolution band produced and six multispectral bands with 20 m spatial resolution by the five fusion methods of PCA,HPF,WT,GS and Pansharp to produce six multispectral bands with 10 m spatial resolution and the fusion results were evaluated from three aspects:qualitative and quantitative(information entropy,average gradient,spectral correlation coefficient,root mean square error and general image quality index) and classification accuracy of fused images.Results show that the fusion quality of Pansharp with the maximum correlation coefficient is better than other fusion methods,and the classification accuracy is slightly lower than the GS with the pixel maximum of the highest classification accuracy and far higher than the original four multispectral image with 10 m spatial resolution.According to the classification accuracy of experimental data,different fusion methods have different advantages in extraction of different ground objects.In application,appropriate schemes should be selected according to actual research needs.This research can provide reference for Sentinel-2 satellite and similar satellite data processing and application.