一种对Gamma分布的SAR图像相干斑去噪方法

M函数是一类特殊的级数，常用于计算冲击模型的寿命分布，本文主要讨论了M函数在其参数δ及参数x趋向无穷大和趋向零的情形下的极限，从而得到了M函数的三个极限性质，进而，利用M函数的极限性质给出了滤过泊松过程一阶矩的简洁证明.

A Denoising Method Aiming at the Speckle of Gamma Distribution SAR Image

After processing by logarithmic transformation, the Gamma distribution speckle of SAR images are analogous to Gasussian distribution. In view of this, a BP neural network restoration denoising method based on particle swarm optimization is proposed. Firstly,noiseless images are process by Gasussian noise.then,the result image and the noiseless images are made training pair,which is used in training the optimizational BP neural network.Lastly,using the BP neural network to restore SAR Images for the purpose of removing speckle.The experiment shows, compared with traditional denoising algorithm, the method can effectively solve the problem of image distortion and edge burring, have fast convergence rate and less iterations,is better in normalized mean square error (NMSE) and peak signal-to-noise ratio (PSNR).