星载SAR遥感影像地形辐射校正——以ALOS PALSAR为例
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摘要
针对地形起伏造成的SAR图像辐射畸变等问题,在分析SAR成像机理及几何结构的基础上,通过推导,构建了基于规则化散射因子及局部入射角的地形辐射校正模型。以ALOS PALSAR为例,依据DEM与卫星轨道参数,采用R-D定位模型及Muhleman半经验模型,在模拟SAR影像的基础上,建立了真实SAR与DEM之间的映射关系,实现了对原始SAR影像的地理编码,提取了局部入射角、投影角及规则化因子等,进行了地形辐射校正,从而消除了面积效应及地形起伏造成的畸变问题。校正后的图像纹理特征更加均匀,散射系数与局部入射角的线性相关性显著降低。该研究对雷达图像的应用具有一定的借鉴意义。
Based on the analysis of the SAR imaging mechanism and geometric structure,through the deduction,the terrain radiation correction model based on regular scattering factor and the local incidence angle was constructed aiming at the problems of radiation distortion of SAR images caused by topographic relief.Taking ALOS PALSAR as an example,according to DEM and satellite orbital parameters,R-D positioning model and Muhleman semiempirical modal are used.Based on the simulation of SAR images,the true mapping relationship between the real SAR and DEM was established,and original SAR images were geocoded.The local incidence angle,projection angle and regularization factor were extracted as well.The terrain radiometric correction was conducted to eliminate area effects and distortion caused by terrain undulations.From the result analysis,the texture features of corrected images are more uniform,and the linear correlation between scattering coefficient and the local incidence angle is significantly reduced.This has specific reference significance for the application of radar images.
Based on the analysis of the SAR imaging mechanism and geometric structure,through the deduction,the terrain radiation correction model based on regular scattering factor and the local incidence angle was constructed aiming at the problems of radiation distortion of SAR images caused by topographic relief.Taking ALOS PALSAR as an example,according to DEM and satellite orbital parameters,R-D positioning model and Muhleman semiempirical modal are used.Based on the simulation of SAR images,the true mapping relationship between the real SAR and DEM was established,and original SAR images were geocoded.The local incidence angle,projection angle and regularization factor were extracted as well.The terrain radiometric correction was conducted to eliminate area effects and distortion caused by terrain undulations.From the result analysis,the texture features of corrected images are more uniform,and the linear correlation between scattering coefficient and the local incidence angle is significantly reduced.This has specific reference significance for the application of radar images.
引文
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[9]刘文祥,张继贤,黄国满,等.地形辐射校正在极化SAR影像分类中的应用[J].测绘科学,2014,39(3):98-102.
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[11]魏丹婷,塔西甫拉提·特依拜,雷磊,等.不同入射角下的雷达后向散射系数图像模拟[J].遥感信息,2012,27(6):54-59.
[12]FRANCESCHETTI G,MIGLIACCIO M,RICCIO D.SARAS:a synthetic aperture radar(SAR)raw signal simulator[J].IEEE Transactions on Geoscience and Remote Sensing,1992,30(1):110-123.
[13]刘智,张永贺,王冬红,等.基于DEM的SAR图像模拟[J].测绘科学技术学报,2008,25(5):317-320.
[14]秦志远,张宝印,靳国旺,等.基于DEM和地物分类信息的SAR图像模拟[J].系统仿真学报,2009(8):2437-2440.
[2]CASTEL T.BEAUDOIN A,STACH N,et al.Sensitivity of space-borne SAR data to forest parameters over sloping terrain.theory and experiment[J],Int.J.Remote Sens,2001,22:2351-2376.
[3]陈尔学,李增元,车学俭,等.星载SAR影像辐射误差校正算法研究[J],高技术通讯,2002(5):10-14.
[4]张永红,张继贤,林宗坚,等.地形引起的雷达辐射畸变及其校正[J].测绘科学,2002,27(4):23-26.
[5]SHIMADA M.Ortho-rectification and slope correction of SAR data using DEM and its accuracy evaluation[J].IEEE Journal of Selected Topics in Applied Earth Observation and Remote Sensing,2010,3(4):657-671.
[6]SMALL D,ZUBERBUEHLER L,SCHUBERT A,et al.Terrain-flattened gamma nought Radarsat-2backscatter[J].Can.J.Remote Sens,2011,37(5):493-499.
[7]郎文辉,磨玲,杨学志,等.宽观测带SAR图像入射角效应量化研究与校正[J].遥感学报,2013,17(5):1288-1294.
[8]SHIMADA M.Ortho-rectification and slope correction of SAR data using DEM and its accuracy evaluation[J].IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing,2010,3(4):657-671.
[9]刘文祥,张继贤,黄国满,等.地形辐射校正在极化SAR影像分类中的应用[J].测绘科学,2014,39(3):98-102.
[10]吴涛,王超,张红.雷达图像模拟研究综述[J].遥感信息,2005,20(4):237-240.
[11]魏丹婷,塔西甫拉提·特依拜,雷磊,等.不同入射角下的雷达后向散射系数图像模拟[J].遥感信息,2012,27(6):54-59.
[12]FRANCESCHETTI G,MIGLIACCIO M,RICCIO D.SARAS:a synthetic aperture radar(SAR)raw signal simulator[J].IEEE Transactions on Geoscience and Remote Sensing,1992,30(1):110-123.
[13]刘智,张永贺,王冬红,等.基于DEM的SAR图像模拟[J].测绘科学技术学报,2008,25(5):317-320.
[14]秦志远,张宝印,靳国旺,等.基于DEM和地物分类信息的SAR图像模拟[J].系统仿真学报,2009(8):2437-2440.