利用经验模态分解方法抑制SAR斑点噪声

提出了一种利用经验模态分解（EMD）方法抑制SAR斑点噪声的方法。利用经验模态分解方法，可以将SAR图像分解为一系列的以空间周期尺度不同为特征的模态，定义空间特征尺度不大于4的为噪声。通过从图像中减掉噪声成分使SAR斑点噪声得以抑制。用这种方法处理SAR图像在斑点抑制和纹理信息保护两方面取得令人满意的结果。

Speckle Suppression Using the Empirical Mode Decomposition

An effective algorithm for suppressing speckle in synthetic aperture radar(SAR)images utilizing the empirical mode decomposition(EMD)method is presented in this paper.The EMD was proposed by Norden E Huang et al .,with which any complicated data set can be decomposed into a finite and often small number of intrinsic mode functions.Contrary to almost all previous methods,this new method is intuitive,direct,a posterior and adaptive,with the basis of the decomposition based on,and derived from,the data.So EMD is quite suitable for analyzing nonlinear and non_stationary data.A line of digital SAR images can be decomposed into a series of modes whose characteristic space scale defined by the space lapse between the extrema is different.The speckle noise is defined by the mode whose space scale is not more than 4.The SAR speckle suppression is implemented by smearing short space scale component in the spatial domain via the EMD.As the EMD is one_dimensional method,we use EMD in the following way.First we process each horizontal row of pixels,then process each column pixel of image. EMD is based on and derived from the data,thus it is adaptive and can preserve the edge information.Application to SAR images has shown that the performance of the algorithm is satisfactory in both smoothing and edge preservation.