Design And Implementation Of Shortwave Infrared Polarization Detection System

Shortwave infrared polarization detection technology combined with the advantages of shortwave infrared imaging and polarization detection,which has a great advantage in penetrating smoke,target detection,and has a special significance in the field of military industry.This thesis used liquid crystal phase modulation technology instead of traditional rotating polarizers to design a shortwave infrared polarization detection system,and proposed a calibration method based on stokes vector measurement for LCVR(liquid crystal variable delay)calibration problems.The detection experiment was carried out,and the results showed the good ability of the shortwave infrared polarization imaging technology.The main work of this thesis is as follows:(1)The polarization transmission characteristics of shortwave infrared radiation were analyzed,and the shortwave infrared polarization detection system was designed.The polarization direction of the incident light was modulated by the electronically controlled LCVR to realize the fast and continuous adjustment of the polarization state.The main errors factors affecting the system measurement accuracy were analyzed,and the experiment of muller matrix calibration under different voltage was carried out.(2)Aiming at the calibration of LCVR in the system,a calibration method based on stokes vector measurement was proposed,and the functional relationship between the system stokes vector and LCVR phase delay was established.By measuring the stokes vector of the light from the system,the LCVR phase was calculated.This method avoids the calculation error caused by the light intensity being too small,without the use of an analyzer,the calibration device and error source were reduced,and then study wavelength,temperature and other factors on the phase delay of LCVR.(3)The field experiment under different scenes were conducted by using the designed shortwave infrared polarization detection system.The intensity detection and polarization detection of the polarized and total polarization at shortware were analyzed qualitatively and quantitatively.The experimental results showed that shortwave infrared imaging combined with polarization detection technology can highlight the contour texture information and improve the detection ability of the target.