Research On Simulation Modeling And Inversion Of Imaging Effect Of Infrared Imaging System

The imaging effect modeling and simulation technology of infrared imaging systems has always received great attention.It has extremely important significance for the design and evaluation of infrared imaging systems,the development of infrared warning or guidance systems,and the generation of all-digital simulation scenes.On the other hand,the inversion of the imaging system through the measured images can extract imaging effects that are more in line with the characteristics of the actual system.It is also a key link in the inversion of the intrinsic temperature field of the scene and the generation of high-realistic simulation scenes.Relying on infrared imaging theory and computer simulation technology,this paper has established a systematic and comprehensive imaging system simulation model,verified the simulation degree of the simulation model through experiments,and researched the imaging system inversion method.The main research of the thesis is divided into the following aspects:First,according to the imaging physical process of the infrared imaging system,a signal transfer characteristic model,a spatial transfer characteristic model,a spatial sampling characteristic model and a spatial-temporal noise characteristic model are established.Based on this,the simulation framework of the infrared imaging system is constructed,and the ray tracing method,the modulation transfer function method and the method based on pixel processing are used to simulate the effects of each imaging system.Secondly,a simulation model verification model with modulation transfer function(MTF),signal transfer function(Si TF)and image quality as evaluation indicators is established.By comparing the measured index results of the medium-wave thermal imager and the long-wave thermal imager with the simulation index results of the simulation model,the verification results show that the various indicators of the simulation model have high similarity,and have good usability and reliability.And select the typical parameters of the optical system,detector and signal processing module in the simulation model,and evaluate the sensitivity with the degree of system modulation transfer function curve change or the degree of difference of the simulated image as the index,and obtain the focal length,clear aperture,D*,NETD,The integration time and low-pass filter 3d B frequency parameters have higher sensitivity.Then,the imaging system inversion was modeled and studied,and an imaging system inversion model including three stages of response data calibration,imaging effect inversion and intrinsic temperature acquisition was established.Aiming at the three main imaging effects of blind element effect,noise effect and modulation transfer effect,according to the different mode of action of each imaging effect,a method for extracting and removing each imaging effect based on the measured image and adding each imaging effect to the ideal image is established.The calculation of blind element rate,Gaussian noise detection method based on PCA analysis and Roberts function image definition evaluation method are used to evaluate the inversion effect of each imaging effect.Finally,the inversion of the imaging system is realized,and the medium-wave thermal imager is selected to calibrate the measurement data to obtain the temperature-level relationship.And based on the measured image,the effective pixel weight compensation method under the adaptive window,the time series image averaging method,the image Fourier transform spectrogram and the MTF template division method are used to achieve the inversion of each imaging effect.The intrinsic temperature corrected by the emissivity is more similar to the actual temperature,which proves that the inversion effect of the imaging system inversion model is better.On this basis,the application of imaging system inversion in imaging system simulation simulation is studied,and combined with the imaging system theoretical model,an imaging system simulation model based on the improvement of inversion is established,which makes the similarity of the simulated images of the imaging system is higher.The imaging system simulation model established in this paper can be applied to image simulation and performance parameter calculation under the infrared imaging system module in the all-digital scene simulation.The result of parameter sensitivity analysis has a certain reference for the design of the real imaging system and the parameter value of the simulation module.In addition,the established imaging system inversion model is also of great significance for the inversion of the intrinsic temperature field and the expansion of infrared imaging product data sets.