高斯型弱散射屏产生的像面散斑场的分布特性研究

Study on the distribution properties of image plane speckle fields produced by Gaussian correlation weak scattering screens

弱散射屏产生的远场散斑由一个中央亮斑和一个分布于亮斑周围而与正态散斑类似的散斑结构,根据弱散射屏远场的散斑图样,人们假设弱散射屏产生的像面散斑为均匀背景与正态散斑两者相干叠加的结果,但这种假设与实际像面散斑存在歧异,基于上述情况,本文利用4f高通滤波光学成像系统,研究了高斯型弱散射屏产生的像面散斑场的统计特性,得出只有表面均方根粗糙度与入射光波的波长相差不多时上述假设才是可行的结论.

Far-field speckle generated by weak scattering screen is a central bright spots, around which is a speckle structure similar to the normal speckle. According to the far-field speckle produced by weak scattering screen, it is assumed that the image plane speckle of weak scattering screen is the result of coherent superposition of both uniform background and normal speckle. However, there exists a discrepancy between the assumption and the actual image plane speckle. Based on the above circumstances, the statistical properties are studied about the image plane speckle fields produced by Gaussian correlation weak scattering screens in the 4 f optical imaging system of high-pass filter. It is found that the above assumption is correct when the surface roughness of the weak scattering screen and the wavelength of the incident light wave are almost the same.