水下距离选通成像系统后向散射光的计算

Optical Backscatter Calculations for an Underwater Range-Gated Imaging System

为了实现在室内测试距离选通成像系统的分辨力,建立了后向散射光模型.分析并给出了典型的脉冲激光照明的水下距离选通成像系统的光学几何结构和相关参数.采用辐射传输理论建立了水下距离选通成像系统的后向散射光模型.编制了相应的计算机程序,根据典型系统参数计算并绘制了系统的重叠系数和后向散射光随时间的变化曲线.结果表明,到达探测器的后向散射通量随时间快速上升,达到最大值后又快速下降,5ns激光脉冲的后向散射辐射通量集中分布在20ns时间间隔内.

To obtain the resolution of a rangegated imaging system in the laboratory, the optical backscatter of seawater arriving at a detector is calculated. Backscatter optical geometry and the related parameters for underwater rangegated imaging system with typical pulsed laser illumination are given and analyzed. Based on the radiation transmition theory, a model of optical backscatter of the underwater rangegated imaging system is given. The theoretical calculations are programmed, and figures of overlap coefficient and optical backscatter plotted based on typical system parameters. The figures obtained show that the backscatter radiant flux arriving at the detector increase rapidly with time, and then declined swiftly after reaching the maximum. The backscatter radiant flux of 5 ns laser pulse has centralized distribution within a 20 ns interval.