Long-Wave Infrared Polarization Imaging And Experimental Study

In modern society,along with the advancement of imaging detection technology,and the increasing demand of people,the range of detection has extended from visible to infrared.Infrared imaging equipment can detect the amount of radiation,such as the target temperature.In the night observation or thermal imaging of the target,infrared imaging equipment is particularly important,which is impossible in the visible light band.However,when the target is concealed by the shelter or the temperature difference between the target and the background is small,the infrared thermal imaging cannot meet the demand at this time.Therefore,people combine the polarization characteristics contained in light with infrared thermal imaging technology to develop infrared polarization imaging technology with higher recognition ability.The development of this technology makes the acquired information not only include the light intensity,but also the polarization information representing the target feature.The combination of the two allows the detection dimension to be expanded,even when the imaging background is complex or the target contrast is small,the infrared polarization imaging device still can identify the object.Different objects have different polarization properties,and even if the same target is in different states,its polarization phenomenon will also be different.At present,most of the measured objects are not static,so imaging only for static targets does not meet the demand.Research on how to perform real-time polarization detection is very necessary.The long-wave infrared band belongs to the emission band of features(including artifacts),so long-wave infrared polarization imaging has important research significance.In this paper,based on the infrared polarization characteristics,in the longwave infrared,the long-wave infrared real-time polarization imaging technology is studied under the two polarization detection methods which is division of time and division of focal plane,and the related research experiments are carried out.Firstly,for the division of time imaging structure,the dynamic target polarization detection that can not be completed by the traditional division of time system,it is realized by adopting the high-speed and high-precision wheel to drive the polarizer,and system has a polarization frame rate of 25 frames per second.Dynamic target polarization detection with a maximum target angular velocity of 0.0084 rad/s under the condition that the focal length is 25 mm and the pixel size is 17 ?m.Then,for the real-time of long-wave infrared division of focal plane polarization imaging structure,interpolation algorithm and image fusion are experimentally studied.The experiment of error compensation algorithm is completed and the polarization characteristic experiment is carried out.As a new type of real-time polarization detection method,the division of focal plane imaging has broad application prospects.Our research work provides theoretical basis and practical experience for the subsequent application of this method.The specific arrangements of the paper are as follows:1.The theory of infrared polarization phenomenon is expounded,and the polarization characteristics under different factors are simulated.The mechanism of infrared polarization generation is deduced in detail.And,the expression forms of polarized light,the imaging principle of polarizing device and several different ways of polarization detection are introduced,which provide basic theoretical basis for the research of polarized imaging experiments.2.First,the long-wave infrared polarization characteristics experiment is carried out on the static target by using the traditional division of time system.Then,the longwave infrared division of time high frame-frequency polarization imaging system is introduced from the aspects of system composition and working principle.The traditional division of time imaging system is only suitable for the detection of static targets.Based on the traditional division of time polarization imaging method,this paper innovatively improves the shortcomings of this system and realizes the real-time polarization imaging of 25 frames per second,with a focal length of 25 mm and a pixel size of 17 ?m,the maximum target angular velocity detectable is 0.0084 rad/s.We use the high-speed and high-precision rotating wheel to drive the polarizer.The maximum speed of the rotating wheel can reach 120°/5ms,60°/4ms,so the division of time high frame rate imaging device is built.Through the continuous improvement of the polarization method,the video frame rate is gradually increased to complete the realtime polarization detection of the long-wave infrared moving target.3.Then the theoretical analysis and related experimental results of the division of focal plane polarization imaging technology are analyzed.The imaging principle of the division of focal plane,the design principle of the micro-polarizer,and the error of the structure are introduced and analyzed.Firstly,the structural characteristics and imaging mechanism of the micro-polarization array of the focal plane are analyzed.Then error of the imaging method is discussed and deduced.The interpolation algorithm is used to compensate the instantaneous field of view error,and the bicubic interpolation's result is better.Then the polarization characteristics related to the space target are analyzed and tested.Finally,fusing the target infrared image and the polarized image.The fused image has both intensity information and detail.These provide a theoretical basis and practical basis for pixel-level real-time polarization detection.