Comparison And Applicability Assessment Of Atmospheric Correction Methods Of OLI Images In Taihu Lake

Obtaining water leaving radiance from satellite images is the primary objective of lake water environment remote sensing.However,the total radiation received by the sensor more than 90%comes from atmospheric scattering and solar reflection,the radiation comes from water body is minimal.Therefore,in order to obtain water information accurately,we must perform high-precision atmospheric correction.At present,atmospheric correction methods for clean water have become more mature,but the problem of atmospheric correction for inland waters with complex optical properties has not been completely resolved.The article uses inland lakes Taihu Lake as a research area,Landsat OLI images from 2016 to 2017 as data sources,based on measured data discussed the correction effects of 6S,FLAASH,QUAC and ACOLITE four atmospheric correction methods.And then evaluate the applicability of the four atmospheric correction methods in Taihu Lake waters.Specific research content and results include:(1)We research and analysis some commonly used atmospheric correction methods,and has carried on the thorough research to 6S method.Based on the 6S method,we achieved 6S atmospheric correction batch processing of OLI images by using MATLAB language.The results show that the 6S batch program is not only easy to operate,but also has the same calibration results as the traditional 6S atmospheric correction method.(2)Atmospheric correction of Taihu Lake OLI image was performed using four atmospheric correction methods.Water reflectivity in the near-infrared region was found in the corrected Taihu Lake OLI image.Based on field-simultaneously measured spectral reflectance,quantitative error relative error RE was used to visually evaluate the effect.The contrast,overall accuracy comparison,single-band accuracy comparison,and band ratio accuracy comparison methods were used to compare and analyze the correction effects of different atmospheric correction methods for OLI images and evaluate the accuracy.The comparison results show that the four atmospheric correction methods can eliminate the influence of the atmosphere to a certain extent;the overall correction accuracy is 6S method;in the single-band accuracy comparison,the 6S method has the highest correction accuracy in the green and red bands,and the ACOLITE method is in blue The accuracy of the band is the highest.The calibration accuracy of the four methods of the sea blue and near-infrared bands is not ideal.Among the band ratios,the four atmospheric correction methods have the highest accuracy in the combination of the green band and the red band,and the ACOLITE method is the most prominent.(3)We have completed appraisal of applicability of four atmospheric correction methods in atmospheric correction of Taihu Lake based on the application effect of the corrected image,and comparison results of different atmospheric correction methods.The results show that the FLAASH and QUAC methods have low calibration accuracy and they are not suitable for Taihu Lake water bodies.ACOLITE method has high accuracy in the ratio of wavebands,when using band ratio build inversion algorithm,we can choose ACOLITE method,in order to reduce the impact of the atmosphere.The 6S method works best in four correction methods,it is most suitable for the Taihu Lake water body.Using Normalized Water Index to retrieve Taihu Lake water area,then complete the application of image evaluation.Experimental results verify the high accuracy of the 6S method in the four methods.At the same time,it provides a reference for follow-up inland lake research.