水下光场的迭代求解  

Iterative solution of underwater scattering light field

作　　者：何大华[1] 李阳阳 周少杰[1] HE Da-hua;LI Yang-yang;ZHOU Shao-jie(Huazhong Institute of Electro-Optics–Wuhan National Laboratory for Optoelectronics,Wuhan 430223,China)

机构地区：[1]华中光电技术研究所—武汉光电国家研究中心,湖北武汉430223

出　　处：《中国光学》2022年第2期297-305,共9页Chinese Optics

基　　金：船舶重工装备预研联合基金(No.6141B042006)。

摘　　要：水体对光线的散射是水下图像质量劣化的重要因素,为了定量分析在特定光源照射下水体散射的影响,建立了光线水下传输的散射模型,以此为基础推导出求解水下光场分布的Fredholm积分方程。在水中光线能量随距离的增大呈指数规律衰减,基于此,在水体体散射函数为常数的情况下,给出了有边界条件时该积分方程的数值迭代求解方法,得到高精度的水下光场分布。以太阳、均匀亮度天空、水下点光源以及空中点光源为例,分别给出了水面平静时的水下光场的计算结果。该求解方法可推广应用于任意光源配置、任意边界条件下的水下光场分布,为严格推导水体点扩展函数及调制传递函数奠定了基础。The scattering of light by water is an important factor in the deterioration of underwater image quality.In order to quantitatively analyze the influence of water scattering under the irradiation of a specific light source,the scattering model of underwater light transmission is established,and the Fredholm integral equation for solving the distribution of underwater light field is derived.Under conditions where the light en-ergy underwater decays exponentially with an increase in distance and the volume scattering function of the water is constant,the numerical iterative solution method of the integral equation with boundary conditions is given and the high-precision underwater light field distribution can be obtained.Taking the sun,uniform sky brightness,and underwater and overwater point light sources as examples,the calculation results of their un-derwater light fields when the water surface is calm are given.This method can be extended to solve the dis-tribution of underwater light fields under arbitrary light source configurations and arbitrary boundary condi-tions,which lays a foundation for strictly deriving a point spread function and modulation transfer function for water bodies.

关 键 词：水下光电成像 水下光场 球面照度 体散射函数 FREDHOLM积分方程 数值计算 

分 类 号：TN29[电子电信—物理电子学] O435.1[机械工程—光学工程]