P波段极化干涉SAR森林高度反演研究

森林高度信息是森林研究必不可少的内容之一,对全球碳循环、森林资源管理以及获取精确的林下地形等具有重要意义。极化干涉SAR技术(PolInSAR)是目前提取森林高度的一种热门的方法,其中,P波段极化干涉SAR由于电磁波的强穿透力使其相比其他波段具有一些独有的特征。文中首先分析P波段极化干涉SAR森林高度反演的优势与不足,然后结合目前主流的森林高度反演算法,提出一种适用于P波段极化干涉SAR高度反演的新方法。该方法通过对非线性迭代算法的初始值进行有效约束,从而解算出相对可靠的消光系数,同时考虑地体幅度比对森林高度的影响,最终得到相对准确的森林高度。最后,将该方法与现有的经典算法及优化算法进行对比,通过对实验结果定性和定量分析,得出在P波段条件下该方法相比三阶段算法精度提高67.5%,相比固定消光系数法精度提高29.8%,验证了该方法的可靠性和优越性。

Extration of forest height from P-band PolInSAR data

Forest height ,as the essential part of forest research ,is an important element to the quantitative analysis of the carbon cycle on a global , w hihc is also helpful for forest resource management and to reconstruct the accurate forest underlying terrain . Polarimetric SAR interferometry (PolInSAR ) is an effective method to estimate forest height .Because of the strong penetration of the electromagnetic wave , the P‐band PolInSAR Data has some unique characteristics compared to the rest .Firstly ,the advantages and disadvantages of P‐band PolInSAR Data are analyzed in this paper . And then , aiming at the disadvantages of P‐band PolInSAR Data ,a new method which is suitable for P‐band PolInSAR Data is invented by combining the main forest algorithm for forest height inversion .For the new method ,reliable extinction can be calculated by providing effective initial value for nonlinear iterative algorithm .At the same time , considering the influence of the ground‐to‐volume scattering ratio , eventually a relatively accurate result can be obtained .Finally ,the experimental results of new method and the existing method are analyzed in this paper .It is concluded that compared with three‐stage inversion process ,the estimation accuracy of new method increases by 67 .5% ,and compared with the method with the fixed extinction ,it increases by 29 .8% ,w hich verifies the reliability and superiority of the new method .