一种基于小波变换的InSAR干涉图滤波方法.pdf

35 2 Vol. 35, No. 2 2006 5 ACTA GEODAETICA et CARTOGRAPHICA SINICA May, 2006 : 1001- 15 5(2006) 02-0128-05 :TP751 :A InSAR 何儒云, 王耀南 ( , 410082) InSAR Interferogram Filtering Based on Wavelet Transform HE Ru-yun, WANG Yao-nan ( College of Electrical and I nf or mation Engineering , H unan Univ ersity, Changsha 410082, China) Abstract:A method for InSAR interferogram filtering based on w avelet transform is proposed. It first decomposes t he InSAR interferogram w ith multilayer using wavelet t ransform, and obtains multilevel approximate coefficient and detail coefficient w ith t hree orientations (horizontal, vertical and diagonal) , then checks the detail coefficient of all the orientat ions at all levels, judges whether every coefficient is the edge of corresponding orientation or not, if yes, smoothes the coefficient using different mode corresponding to its orientation, then filters the coefficient using median filtering, ot herw ise filters the coefficient using median filtering directly. The experiment results using real InSAR interferogram show that this method is efficient. Key words:w avelet transform; direction checking; median filtering; InSAR interferogram : 提出一种基于小波变换的 InSAR 干涉图滤波算法, 此算法先用小波变换对干涉图数据做多级分解, 得 到图像的多级 似部分系数和3 个( 水平垂直对角线) 方向的细节部分系数, 然后分别对每 一级各 个方向的 细节部分系数检测其是否为对应方向的边缘, 对边缘处的系数根据边缘的方向不同, 用不同的方向模板平滑 后, 再中值滤波; 对非边缘处的系数直接中值滤波用真实的 InSAR 干涉图实验结果证明此方法具有较好的 滤波效果 : 小波变换; 方向检测; 中值滤波; InSAR 干涉图 1 引 言 [ 1] 20 , ( InSAR, , InSAR , Inter