全偏極干涉最佳化技術於樹高反演的理論分析; Theoretical Analysis of Retrieval of Forest Height Based on Coherence Optimization in Pol-InSAR

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題名:	全偏極干涉最佳化技術於樹高反演的理論分析;Theoretical Analysis of Retrieval of Forest Height Based on Coherence Optimization in Pol-InSAR
作者:	孫瑜旋;Sun,Yu-syuan
貢獻者:	遙測科技碩士學位學程
關鍵詞:	全偏極干涉雷達;樹高反演;Pol-InSAR;Estimation of tree height
日期:	2013-07-29
上傳時間:	2013-08-22 12:14:00 (UTC+8)
出版者:	國立中央大學
摘要:	極化合成孔徑雷達利用發射與接收不同偏極的機制，獲得目標物的散射矩陣，此散射矩陣可充分的描述電磁波與目標物的交互作用情形，而干涉合成孔徑雷達則是於兩次拍攝中，利用接收天線與目標物的幾何關係獲得相位資訊，進而轉換為地表高度。全偏極干涉雷達技術即結合了極化合成孔徑雷達技術與干涉合成孔徑雷達技術，包含兩者的優點。特別是於植被區域觀測時，傳統干涉合成孔徑雷達技術對於植被體的散射中心無法有效分辨，但在結合全偏極雷達系統後，可利用不同偏極的干涉資訊進行植被區域的參數反演。本研究主要分為三個部分，複相關係數的最佳化、隨機植被體疊加地表模型的建立及植被參數的反演。首先利用極化複相關係數的最佳化於資料前處理，將不同散射機制的相位中心有效區分。在隨機植被體疊加地表模型的條件下，說明植被參數反演的基本原理並分析三階段反演方法。然而，因模型建立時包含許多假設，於真實情形有所差異，利用德國國家太空中心L波段機載的觀測資料進行驗證，討論分析其估算結果。並利用衛載資料進一步說明此方法的適用性與未來改善空間。 Fully polarimetric synthetic aperture radar(SAR) makes use of the polarimetric response of each pixel within the imaged area. The polarimetric response is highly sensitive to the scattering mechanism of a pixel. In Interferometric SAR, the surface height is derived from phase information induced by the geometry between SAR antennas and targets. Pol-InSAR technique combines the interferometric information and the polarimetric parameters of the target, especially in the vegetation area, where the scattering centers is difficult to be distinguished by single-polarized interferometric SAR. As such, Pol-InSAR has been widely studied in vegetation parameters inversion. This study consists of three parts: coherence optimization, development of a Random Volume over Ground model(RVoG) and vegetation parameters inversion. We attack these from theoretical analysis point of view. First, coherence optimization method is used to preprocess the data so that the phase center of scatterers under different scattering mechanisms can be distinguished effectively. Based on the RVoG model, vegetation parameters inversion is exploited, in particular the three-stage inversion method is analyzed. Validation is made using DLR L-band E-SAR data and satellite C-band Radarsat-2 SAR imagery. Results reveal that there remains drawbacks of the inversion method, largely due to oversimplified RVoG model used in the inversion. The assumptions on which RVoG model based may violate physical conditions and should be modified before the inversion of physical parameters by means of Pol-InSAR can be better applied.
顯示於類別:	[遙測科技碩士學位學程] 博碩士論文

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