激光遥感偏振成像系统光学元件调整及误差分析

改进了利用双旋转波片方法进行偏振成像的实验装置,提出了通过一次测量获得目标偏振度和强度编码图像的方法.运用光强法对激光遥感偏振成像装置的光学元件进行调整,通过斯托克斯和穆勒矩阵在偏振光学元件中的应用,给出了相应光学元件的调整原理、方法及过程.分析了激光器中心波长变动、偏振片的角度误差和波片的相位延迟及角度误差对整个系统的影响.结果表明,由偏振片角度和波片角度误差造成的出射光斯托克斯误差较小,不超过0.001,可以忽略;由波片相位延迟不精确造成的误差在0.02左右,所以应采用延迟精度较高的波片;激光器中心波长变化的影响最大,不能忽略,必须加滤光片使接收光的中心波长控制在808nm;镀有铝膜望远镜对接收到的散射光偏振度影响较小,适于激光遥感偏振成像系统的应用.

Adjustment of Optical Elements and Error Analysis for Laser Remote Sensing Polarization Imaging System

The experimental setup for polarization imaging based on dual-rotating-retarder technique is modified, and a method to obtain two images encoded by polarization degree and intensity with a single measurement process is proposed. The optical intensity method is used to the laser remote sensing polarization imaging equipment. Through the application of Stokes and Mueller matrices for polarization elements, the principle, method and process of corresponding optical elements adjustment are given. The influence of laser central wavelength variation, polarizer angle error, wave plate phase retardance and angle errors on the whole system is analyzed. The results show that the emitted Stokes error caused by the angle error of polarizer and wave plate is less than 0.001, and can be neglected. The error caused by the retardance accuracy of wave plate is about 0.02, so the wave plate with higher accuracy should be selected. The influence caused by variation of laser central wavelength is the largest, and cannot be neglected, so a filter should be added to control the central wavelength of the received light at 808 nm. Telescope coated with aluminium has little influence on the polarization degree of scattered light, and it is suitable for the laser remote sensing polarization imaging system.